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How NASA Repaired Voyager 1 From 15 Billion Miles Away · Boring Science

• 0:00
  Speaker 1: A computer chip failed 15 billion miles from Earth. The
• 0:04
  Speaker 1: engineers who built it are retired or dead. The documentation
• 0:09
  Speaker 1: exists only on yellowed paper and fading mimeographs. And every
• 0:15
  Speaker 1: command you send takes 45 hours to get a response.
• 0:19
  Speaker 1: This is the story of how NASA saved Voyager 1.
• 0:23
  Speaker 1: On November 14th, 2023, humanity's most distant ambassador went silent.
• 0:31
  Speaker 1: Not completely silent. Voyager 1 was still out there, still
• 0:36
  Speaker 1: receiving commands, still functioning. But when it tried to speak back,
• 0:42
  Speaker 1: all that came through was gibberish. A repeating pattern of
• 0:46
  Speaker 1: ones and zeros that meant absolutely nothing. For five months,
• 0:52
  Speaker 1: a dozen engineers at NASA's Jet Propulsion Laboratory worked to
• 0:57
  Speaker 1: diagnose a problem they couldn't see on hardware they couldn't touch,
• 1:02
  Speaker 1: using technology older than most of their colleagues. The spacecraft
• 1:07
  Speaker 1: was so far away that light itself, the fastest thing
• 1:11
  Speaker 1: in the universe, took nearly a full day to reach it.
• 1:16
  Speaker 1: What they accomplished represents one of the most extraordinary remote
• 1:20
  Speaker 1: repairs ever attempted. But to understand why this matters, you
• 1:26
  Speaker 1: need to understand what Voyager 1 actually is. In 1977,
• 1:38
  Speaker 1: a rare planetary alignment occurred, something that happens once every
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  Speaker 1: 175 years. The outer planets of our solar system lined
• 1:50
  Speaker 1: up in such a way that a spacecraft could visit
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  Speaker 1: multiple worlds using gravity assists. slingshotting from one planet to
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  Speaker 1: the next. Without this alignment, a trip to Neptune would
• 2:02
  Speaker 1: take 30 years. With it, 12. NASA built two spacecraft
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  Speaker 1: to take advantage of this cosmic opportunity. Voyager 1 and
• 2:14
  Speaker 1: Voyager 2 launched that summer, carrying instruments to study Jupiter, Saturn,
• 2:19
  Speaker 1: and their moons. The mission was designed to last five years,
• 2:25
  Speaker 1: The spacecraft were built accordingly, robust enough to survive the journey,
• 2:30
  Speaker 1: but not necessarily engineered for decades of operation. They exceeded
• 2:36
  Speaker 1: every expectation. Voyager 1's journey through the solar system revealed
• 2:42
  Speaker 1: worlds we'd only glimpsed through telescopes. At Jupiter, it discovered
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  Speaker 1: active volcanoes on Io, the first time volcanic activity had
• 2:52
  Speaker 1: been observed anywhere beyond Earth. Nine volcanoes erupting into space,
• 3:00
  Speaker 1: driven by tidal forces from Jupiter's immense gravity. Four months later,
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  Speaker 1: Voyager 2 passed by and found eight of those nine
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  Speaker 1: volcanoes still active. At Saturn, Voyager 1 revealed the intricate
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  Speaker 1: structure of the planet's rings, discovered new moons, and provided
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  Speaker 1: the first detailed images of Titan's atmosphere Then it did
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  Speaker 1: something remarkable. Instead of continuing to Uranus and Neptune like
• 3:32
  Speaker 1: its twin, Voyager 1 used Saturn's gravity to fling itself upward,
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  Speaker 1: out of the plane of the solar system, heading toward
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  Speaker 1: interstellar space. By 2012, Voyager 1 had traveled so far
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  Speaker 1: that it crossed the heliopause, the boundary where the Sun's
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  Speaker 1: influence ends and interstellar space begins. It became the first
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  Speaker 1: human-made object to leave the solar system, and it kept going.
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  Speaker 1: The spacecraft itself is deceptively simple. Three computers, built in
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  Speaker 1: the 1970s, with a combined memory of 68 kilobytes. Your
• 4:16
  Speaker 1: smartphone has millions of times more computing power. The button
• 4:21
  Speaker 1: you press to unlock your car door has more processing
• 4:25
  Speaker 1: capability than Voyager's entire system. But here's what makes those
• 4:30
  Speaker 1: computers remarkable. They've been running continuously for nearly 50 years,
• 4:37
  Speaker 1: through temperature extremes, cosmic radiation, and the vacuum of space.
• 4:43
  Speaker 1: They've processed data from planetary flybys, managed course corrections, and
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  Speaker 1: maintained communication with Earth across distances, that make the mind real.
• 4:55
  Speaker 1: Until November 2023, when one of them broke. The Flight
• 5:01
  Speaker 1: Data Subsystem, the FDS, is responsible for collecting information from
• 5:08
  Speaker 1: all of Voyager's scientific instruments and engineering sensors, organising it
• 5:13
  Speaker 1: into a coherent format, and preparing it for transmission back
• 5:17
  Speaker 1: to Earth. It's the spacecraft's voice, essentially. The system that
• 5:23
  Speaker 1: takes raw measurements and turns them into data, we can understand.
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  Speaker 1: When it failed, Voyager 1 didn't go completely dark. It
• 5:34
  Speaker 1: could still hear us. Commands sent from Earth were received
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  Speaker 1: and executed normally. But when the spacecraft tried to respond,
• 5:43
  Speaker 1: when it tried to send back the data it was collecting,
• 5:47
  Speaker 1: all that came through was noise. NASA described it as
• 5:52
  Speaker 1: a repeating pattern of ones and zeros. The spacecraft was
• 5:57
  Speaker 1: stuck in a loop, sending the same meaningless sequence over
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  Speaker 1: and over. It was like talking to someone who could
• 6:05
  Speaker 1: understand everything you said, but could only respond with the
• 6:08
  Speaker 1: same nonsensical phrase. The engineering team knew they had to
• 6:13
  Speaker 1: diagnose the problem, but the challenge they faced was unlike
• 6:19
  Speaker 1: anything in typical computer repair. You can't reboot Voyager 1.
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  Speaker 1: You can't plug in a monitor and see what's happening.
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  Speaker 1: You can't swap out components or run diagnostic tools directly.
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  Speaker 1: And then there's the distance. Voyager 1 is currently over
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  Speaker 1: 15 billion miles from Earth. Light, travelling at 186,000 miles
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  Speaker 1: per second, takes 22 and a half hours to reach
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  Speaker 1: the spacecraft. Another 22 and a half hours for the
• 6:52
  Speaker 1: response to come back. Every single interaction with Voyager requires
• 6:58
  Speaker 1: a minimum of 45 hours. Imagine debugging code with a
• 7:04
  Speaker 1: 45-hour delay between each command and its result. You can't
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  Speaker 1: iterate quickly. You can't try something, see it fail, and
• 7:14
  Speaker 1: immediately try something else. Every attempt requires careful planning, thorough review,
• 7:21
  Speaker 1: and two full days of waiting. Make a mistake, and
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  Speaker 1: you might make things worse. Or you might permanently disable
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  Speaker 1: the spacecraft. The team started with what they knew. Voyager
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  Speaker 1: has three computers. The FDS, the Command Control System, and
• 7:39
  Speaker 1: the Attitude and Articulation Control System. The Command Control System
• 7:45
  Speaker 1: was clearly working. It was receiving and executing commands. The
• 7:50
  Speaker 1: AACS was also functioning. The spacecraft maintained its orientation, keeping
• 7:57
  Speaker 1: its antenna pointed at Earth. So the problem had to
• 8:01
  Speaker 1: be in the FDS. But what specifically had failed? For months,
• 8:07
  Speaker 1: the engineers sent commands, trying to coax any kind of
• 8:11
  Speaker 1: meaningful response from the spacecraft. They reviewed decades-old documentation. trying
• 8:18
  Speaker 1: to understand how the original designers had structured the system.
• 8:23
  Speaker 1: Many of those designers were retired, some had passed away.
• 8:27
  Speaker 1: The team was essentially doing archaeology, piecing together the thinking
• 8:32
  Speaker 1: of engineers from nearly half a century ago. Then, in
• 8:36
  Speaker 1: early March 2024, they tried something different. They sent what
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  Speaker 1: they called a POKE command, essentially asking the FDS, to
• 8:47
  Speaker 1: try running different sequences within its software. The hope was
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  Speaker 1: that the spacecraft might be able to work around whatever
• 8:55
  Speaker 1: was broken and resume normal operations. On March 3rd, something changed.
• 9:03
  Speaker 1: The signal coming back from Voyager 1 looked different. There
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  Speaker 1: was activity from one section of the FDS that stood
• 9:12
  Speaker 1: out from the rest of the garbled data. It still
• 9:15
  Speaker 1: wasn't in the normal format, but it was something new.
• 9:19
  Speaker 1: An engineer with NASA's Deep Space Network, the global system
• 9:23
  Speaker 1: of massive radio antennas that communicate with distant spacecraft, was
• 9:28
  Speaker 1: able to decode it. What they found was extraordinary, a
• 9:33
  Speaker 1: complete readout of the FDS memory. It was like a
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  Speaker 1: patient who couldn't speak suddenly handing you their complete medical record.
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  Speaker 1: The team compared this memory dump to documentation of how
• 9:47
  Speaker 1: the FDS should normally function. And there, buried in the data,
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  Speaker 1: they found the problem. 3% of the FDS memory was corrupted.
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  Speaker 1: 3% doesn't sound like much, but in a computer with
• 10:03
  Speaker 1: only 68 kilobytes of total memory, 3% corruption was enough
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  Speaker 1: to completely disable the system. And the team could see
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  Speaker 1: exactly which memory chip had failed. A single chip. responsible
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  Speaker 1: for storing a portion of the FDS memory, including some
• 10:23
  Speaker 1: of the computer's software code, wasn't working. After 46 years
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  Speaker 1: of continuous operation, after countless thermal cycles, after exposure to
• 10:34
  Speaker 1: radiation in interstellar space, one component had finally given up.
• 10:40
  Speaker 1: The question was, could they work around it? You can't
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  Speaker 1: replace a chip on Voyager 1, You can't send up
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  Speaker 1: a repair mission. The spacecraft is in interstellar space, traveling
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  Speaker 1: at 38,000 miles per hour, getting farther from Earth every second.
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  Speaker 1: Whatever solution the engineers devised had to work with the
• 11:02
  Speaker 1: hardware exactly as it existed, 15 billion miles away. The
• 11:08
  Speaker 1: team came up with a plan that was elegant in concept,
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  Speaker 1: but staggeringly complex in execution. They could move the affected
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  Speaker 1: code to a different location in the FDS memory. The
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  Speaker 1: problem was that no single location had enough space to
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  Speaker 1: hold all of it. The code would have to be
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  Speaker 1: divided into sections and stored in multiple places. But it
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  Speaker 1: wasn't as simple as just copying and pasting files. Each
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  Speaker 1: section of code had to be modified to work in
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  Speaker 1: its new location. Every reference to the code's original location
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  Speaker 1: throughout the entire FDS memory had to be updated. The
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  Speaker 1: sections all had to function together as a cohesive whole,
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  Speaker 1: even though they were now scattered across different parts of
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  Speaker 1: the computer's memory. And they had to do all of
• 12:05
  Speaker 1: this with 68 kilobytes of total memory, 3% of which
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  Speaker 1: was now completely unusable. The engineers started making difficult choices.
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  Speaker 1: They identified code that was no longer needed, routines designed
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  Speaker 1: for high data rates during planetary flybys, which were irrelevant
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  Speaker 1: now that Voyager was in the sparse environment of interstellar space.
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  Speaker 1: Code used to process data from Jupiter, functions that hadn't
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  Speaker 1: been used in decades. They deleted what they could. They
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  Speaker 1: reorganized what remained, and they carefully, methodically prepared the modified
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  Speaker 1: code for transmission to Voyager 1. The first phase focused
• 12:51
  Speaker 1: on the code responsible for packaging engineering data, information about
• 12:57
  Speaker 1: the spacecraft's health and status. This was strategic. If the
• 13:02
  Speaker 1: repair worked, engineers would immediately be able to see how
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  Speaker 1: Voyager was doing, which systems were functioning properly, whether there
• 13:12
  Speaker 1: were other problems lurking. If it failed, they could try
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  Speaker 1: again without losing the ability to receive scientific data. On
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  Speaker 1: April 18th, 2024, they transmitted the command. Then, they waited.
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  Speaker 1: 45 hours, almost two full days. the signal crawling across
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  Speaker 1: 15 billion miles of empty space at the speed of light.
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  Speaker 1: On April 20th, the response came back. It worked. For
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  Speaker 1: the first time in five months, Voyager 1 was sending
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  Speaker 1: coherent engineering data. The repair had succeeded. After months of troubleshooting,
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  Speaker 1: after poring over yellow documentation, after carefully crafting each command,
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  Speaker 1: The team had done it. They had fixed a computer
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  Speaker 1: from 15 billion miles away. But the work wasn't finished.
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  Speaker 1: The engineering data was flowing, but the scientific instruments were
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  Speaker 1: still silent. Those instruments, studying plasma waves, magnetic fields, cosmic rays,
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  Speaker 1: particles in interstellar space, represented the entire reason Voyager 1
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  Speaker 1: was still operating. Getting them back online would require relocating
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  Speaker 1: more sections of code. The team continued their work. On
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  Speaker 1: May 19th, they transmitted the commands to restore scientific operations,
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  Speaker 1: and one by one, the instruments came back online. By
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  Speaker 1: June 2024, all four scientific instruments were back online and
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  Speaker 1: transmitting data. But this wasn't just about getting sensors working again.
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  Speaker 1: These instruments were measuring things no human-made object had ever
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  Speaker 1: measured before. Plasma waves rippling through interstellar space. Magnetic fields
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  Speaker 1: from sources we barely understand. Cosmic rays that have travelled
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  Speaker 1: millions of years through the galaxy. Every data point was unique, irreplaceable.
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  Speaker 1: And here's what makes this even more remarkable. Those instruments
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  Speaker 1: weren't designed to work in interstellar space. They were built
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  Speaker 1: to study Jupiter and Saturn during flybys that were supposed
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  Speaker 1: to last a few months. The designers never imagined they'd
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  Speaker 1: still be operating 47 years later in an environment they'd
• 15:54
  Speaker 1: never tested for. The repair revealed something profound about engineering.
• 16:00
  Speaker 1: You can build something incredibly robust without knowing exactly what
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  Speaker 1: challenges it'll face. The Voyager team in the 70s built
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  Speaker 1: redundancy into systems they didn't fully need. They added backup
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  Speaker 1: modes for failures they couldn't predict. They created fault protection
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  Speaker 1: routines for scenarios they couldn't imagine. And decades later, those
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  Speaker 1: decisions saved the mission. But let's talk about what this
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  Speaker 1: repair actually means for how long Voyager can keep going.
• 16:32
  Speaker 1: Because that's the question everyone wants answered. How much longer
• 16:37
  Speaker 1: until we lose contact forever? The honest answer is complicated.
• 16:42
  Speaker 1: Voyager's death won't be sudden. It'll be gradual. System by system.
• 16:48
  Speaker 1: Instrument by instrument. Power is the limiting factor. Voyager's electricity
• 16:55
  Speaker 1: comes from radioisotope thermoelectric generators. Essentially nuclear batteries. that convert
• 17:03
  Speaker 1: heat from decaying plutonium into electrical current. When Voyager launched,
• 17:10
  Speaker 1: those generators produced about 470 watts. Nearly 50 years later,
• 17:17
  Speaker 1: that's dropped to around 220 watts. And it keeps dropping,
• 17:22
  Speaker 1: about 4 watts per year. Every year, the engineers have
• 17:27
  Speaker 1: to make choices about what to turn off. They've already
• 17:31
  Speaker 1: shut down heaters for most of the scientific instruments. Those
• 17:35
  Speaker 1: instruments were tested to specific temperature ranges before launch, and
• 17:40
  Speaker 1: they're now operating well below those limits. The fact that
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  Speaker 1: they still work is surprising, but eventually something will get
• 17:49
  Speaker 1: too cold and stop functioning. They've turned off backup systems,
• 17:54
  Speaker 1: redundant computers, safety features, anything non-essential. They're running on the
• 18:00
  Speaker 1: absolute minimum power configuration needed to maintain contact with Earth
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  Speaker 1: and collect science data. Current projections suggest that by the
• 18:11
  Speaker 1: early 2030s, there won't be enough power to run even
• 18:16
  Speaker 1: a single scientific instrument. Maybe 2031. Maybe 2036. The uncertainty
• 18:26
  Speaker 1: comes from not knowing exactly how the power will decline
• 18:30
  Speaker 1: and which systems will fail first. But here's where it
• 18:34
  Speaker 1: gets interesting. Even after the science instruments shut down, Voyager
• 18:40
  Speaker 1: might still be able to send engineering data. Temperature readings,
• 18:45
  Speaker 1: power levels, attitude information. That data would tell us about
• 18:51
  Speaker 1: the spacecraft's health and about conditions in interstellar space, even
• 18:57
  Speaker 1: without dedicated science instruments. That could extend the mission another
• 19:02
  Speaker 1: few years. Maybe until 2036 or 2037. And then? Then
• 19:10
  Speaker 1: Voyager will finally go silent. Not because it stops working,
• 19:15
  Speaker 1: but because it won't have enough power to run its transmitter.
• 19:19
  Speaker 1: The spacecraft will continue flying through space, still executing its
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  Speaker 1: onboard programming, still taking measurements that no one will ever receive.
• 19:30
  Speaker 1: It'll become a ghost ship, a time capsule containing the
• 19:35
  Speaker 1: Golden Record, that gold-plated copper disk with sounds and images
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  Speaker 1: from Earth, designed for any civilization that might someday find it.
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  Speaker 1: But before we get sentimental, there's another challenge looming. Distance.
• 19:52
  Speaker 1: Voyager is currently about 15 billion miles from Earth. By
• 19:57
  Speaker 1: November 2026, it'll reach what's called One Light Day. The
• 20:03
  Speaker 1: distance light travels in 24 hours. At that point, Engineers
• 20:07
  Speaker 1: send a command at 8am on Monday. They'll get a
• 20:11
  Speaker 1: response at 8am on Wednesday. Think about what that means
• 20:15
  Speaker 1: for troubleshooting. Right now, with a 45-hour round trip, if
• 20:20
  Speaker 1: something goes wrong, you can send a diagnostic command on
• 20:24
  Speaker 1: Monday and get results back Wednesday morning. You can analyse that,
• 20:29
  Speaker 1: prepare a fix, send it Wednesday afternoon, and see if
• 20:34
  Speaker 1: it worked Friday morning. At one light day, that becomes
• 20:38
  Speaker 1: Monday to Wednesday. Analysis Wednesday. Fix sent Thursday. Results Saturday.
• 20:46
  Speaker 1: The whole process takes a week, and Voyager keeps getting
• 20:50
  Speaker 1: farther away. The troubleshooting process keeps getting slower. Each repair
• 20:56
  Speaker 1: attempt requires more patience, more planning, more precision. The engineers
• 21:02
  Speaker 1: working on Voyager today are acutely aware they might be
• 21:06
  Speaker 1: the last generation to interact with it. When Voyager finally
• 21:10
  Speaker 1: goes silent, that silence will be permanent. There's no way
• 21:15
  Speaker 1: to restart it, no way to send a repair mission.
• 21:19
  Speaker 1: Once the power runs out, humanity's most distant ambassador becomes
• 21:24
  Speaker 1: an artifact. But here's something that doesn't get talked about enough.
• 21:29
  Speaker 1: the deep space network that listens to Voyager. That's not
• 21:34
  Speaker 1: getting any younger either. The DSN consists of three antenna complexes,
• 21:40
  Speaker 1: one in California, one in Spain, one in Australia, positioned
• 21:46
  Speaker 1: roughly 120 degrees apart around the globe so that at
• 21:50
  Speaker 1: least one can always see Voyager. These antennas are massive.
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  Speaker 1: The largest are 70 metres in diameter. about 230 feet across.
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  Speaker 1: They're among the most sensitive radio receivers ever built, capable
• 22:07
  Speaker 1: of detecting signals that arrive at Earth with less power
• 22:11
  Speaker 1: than it takes to run a digital watch. But they're
• 22:14
  Speaker 1: also aging infrastructure that requires constant maintenance, and they're in
• 22:19
  Speaker 1: constant demand. Dozens of missions rely on the DSN, Mars rovers,
• 22:26
  Speaker 1: asteroid probes, the James Webb Space Telescope, they're all competing
• 22:32
  Speaker 1: for antenna time. As Voyager gets farther away and its
• 22:36
  Speaker 1: signal gets weaker, it needs more and more antenna time
• 22:41
  Speaker 1: to collect the same amount of data. Eventually, the DSN
• 22:46
  Speaker 1: might have to make hard choices about how much time
• 22:50
  Speaker 1: to dedicate to a mission that's producing diminishing returns. That's
• 22:55
  Speaker 1: not a criticism. It's just reality. The DSN is a
• 23:01
  Speaker 1: limited resource, and new emissions might provide more scientific value
• 23:06
  Speaker 1: per hour of antenna time. But there's something profoundly moving
• 23:10
  Speaker 1: about the effort being poured into keeping Voyager alive. This
• 23:15
  Speaker 1: isn't about maximizing return on investment. It's about not giving
• 23:20
  Speaker 1: up on something we sent into the darkness. The engineers
• 23:24
  Speaker 1: who fixed Voyager in 2024 weren't thinking about cost-benefit analysis.
• 23:31
  Speaker 1: They were thinking about the fact that this spacecraft has
• 23:34
  Speaker 1: been flying for 47 years through conditions no one predicted,
• 23:40
  Speaker 1: sending back data no one else can collect. They were
• 23:44
  Speaker 1: thinking about the original team who built it in the 70s,
• 23:49
  Speaker 1: about the scientists who studied its Jupiter and Saturn data,
• 23:54
  Speaker 1: about the fact that Voyager is doing something unprecedented, measuring
• 23:59
  Speaker 1: the space between the stars. And maybe they were thinking
• 24:03
  Speaker 1: about what it means to be human, to send something
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  Speaker 1: into the void and keep listening for its voice decades later.
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  Speaker 1: Because that's what this repair really represents. It's not just
• 24:16
  Speaker 1: about fixing a computer, it's about maintaining a connection across
• 24:21
  Speaker 1: 15 billion miles about refusing to let distance and time
• 24:27
  Speaker 1: sever the link between us and something we created. The
• 24:32
  Speaker 1: repair also revealed how much institutional knowledge is required to
• 24:36
  Speaker 1: keep these old missions running. The engineers working on Voyager
• 24:41
  Speaker 1: today aren't the ones who built it. They're working with
• 24:44
  Speaker 1: documentation from the 70s, yellowed papers, old mimeographs, design notes
• 24:51
  Speaker 1: written by people who've since retired or passed away. They're
• 24:54
  Speaker 1: essentially archaeologists piecing together the thinking of engineers from 50
• 24:59
  Speaker 1: years ago. Why did they design this system this way?
• 25:04
  Speaker 1: What were they trying to accomplish? What assumptions did they make?
• 25:08
  Speaker 1: It's reverse engineering decisions made before many of the current
• 25:12
  Speaker 1: team members were born. And that knowledge is fragile. Every year,
• 25:18
  Speaker 1: more of the original Voyager engineers retire. More institutional memory disappears.
• 25:26
  Speaker 1: The current team is racing to document everything they learn,
• 25:30
  Speaker 1: to preserve the knowledge for whoever comes after them. Because
• 25:34
  Speaker 1: even though Voyager will eventually go silent, the mission isn't over.
• 25:40
  Speaker 1: When the spacecraft finally stops transmitting, engineers will still need
• 25:44
  Speaker 1: to understand what happened. They'll analyze the final data. They'll
• 25:50
  Speaker 1: write reports documenting the end of the mission. They'll study
• 25:54
  Speaker 1: what failed and why. And that knowledge will inform future missions.
• 26:00
  Speaker 1: Every lesson learned from Voyager, about radiation damage, about thermal cycling,
• 26:08
  Speaker 1: about memory corruption, gets passed forward to the next generation
• 26:13
  Speaker 1: of spacecraft. In that sense, Voyager's legacy extends far beyond
• 26:19
  Speaker 1: its own operation. It's teaching us how to build things
• 26:22
  Speaker 1: that last, how to design systems that can handle the unexpected,
• 26:29
  Speaker 1: how to create machines that keep working decades past their
• 26:33
  Speaker 1: intended lifespan. The October 2024 incident provided another example. Voyager's
• 26:42
  Speaker 1: fault protection system kicked in and switched from its main
• 26:46
  Speaker 1: X-band transmitter to the backup S-band transmitter, a radio that
• 26:51
  Speaker 1: hadn't been used since 1981. The S-band operates at a
• 26:57
  Speaker 1: lower frequency, which means the signal is even weaker when
• 27:01
  Speaker 1: it reaches Earth. Finding that signal after 43 years was
• 27:07
  Speaker 1: like trying to hear a whisper from across an ocean.
• 27:11
  Speaker 1: But the Deep Space Network found it. They detected that
• 27:15
  Speaker 1: impossibly faint signal and re-established contact, and then they carefully
• 27:21
  Speaker 1: switched Voyager back to its main transmitter without causing any
• 27:25
  Speaker 1: additional problems. That whole event demonstrated both the spacecraft's built-in
• 27:32
  Speaker 1: resilience and the ongoing challenge of operating at such extreme distances.
• 27:38
  Speaker 1: Voyager is still protecting itself, making autonomous decisions when communication
• 27:43
  Speaker 1: with Earth takes too long. The spacecraft is, in some sense,
• 27:49
  Speaker 1: taking care of itself, making choices to preserve its own
• 27:54
  Speaker 1: survival without waiting for human input. And that autonomy becomes
• 28:00
  Speaker 1: more important as distance increases. The farther Voyager gets, the
• 28:06
  Speaker 1: more it needs to handle problems on its own, because
• 28:10
  Speaker 1: the round-trip communication time keeps growing. By the time we
• 28:15
  Speaker 1: lose contact, Voyager will be making all its decisions independently,
• 28:22
  Speaker 1: following programming written decades ago by engineers who couldn't possibly
• 28:26
  Speaker 1: have predicted every scenario it would face. It's a strange thought.
• 28:32
  Speaker 1: This machine, built by humans, will eventually operate completely beyond
• 28:38
  Speaker 1: human influence. still executing instructions, still following its mission profile,
• 28:45
  Speaker 1: but entirely alone in the darkness between stars. The repair
• 28:50
  Speaker 1: in 2024 might be the last major fix we're able
• 28:54
  Speaker 1: to perform. The next time something goes wrong, we might
• 28:59
  Speaker 1: not have enough power to implement a solution, or the
• 29:03
  Speaker 1: problem might be in a system we can't access remotely,
• 29:07
  Speaker 1: or we might simply run out of time, as the
• 29:10
  Speaker 1: spacecraft moves farther away. But for now, Voyager is working.
• 29:16
  Speaker 1: All four science instruments are collecting data. The engineering systems
• 29:21
  Speaker 1: are healthy. The spacecraft is flying through interstellar space, measuring
• 29:27
  Speaker 1: conditions that nothing else can reach. And every day, that
• 29:31
  Speaker 1: impossibly faint signal reaches Earth, carrying information from the edge
• 29:36
  Speaker 1: of human exploration. A whisper. from 15 billion miles away,
• 29:43
  Speaker 1: transmitted by a machine that refuses to stop working. The
• 29:47
  Speaker 1: data Voyager sends back now is different from what it
• 29:50
  Speaker 1: transmitted during the planetary encounters. Back then, the spacecraft had
• 29:56
  Speaker 1: power to spare and could transmit at high rates. images
• 30:01
  Speaker 1: of Jupiter's storms, close-ups of Saturn's rings, video sequences showing
• 30:07
  Speaker 1: volcanic eruptions on Io. The bandwidth was enormous compared to
• 30:13
  Speaker 1: what's available today. Now, with power supplies depleted and distant
• 30:18
  Speaker 1: stretching signal strength to its absolute limit, Voyager transmits at
• 30:23
  Speaker 1: speeds measured in bits per second, not kilobits, not megabits.
• 30:30
  Speaker 1: individual bits trickling across 15 billion miles of empty space.
• 30:35
  Speaker 1: A single image that took minutes to transmit in 1980
• 30:39
  Speaker 1: would take weeks today. So the mission has adapted. Instead
• 30:44
  Speaker 1: of pictures, Voyager sends measurements, readings from instruments that detect
• 30:50
  Speaker 1: magnetic fields, plasma waves, cosmic rays, data that can be
• 30:55
  Speaker 1: compressed into tiny packages and transmitted slowly but continuously. The
• 31:02
  Speaker 1: spacecraft is no longer a photographer documenting alien worlds. It's
• 31:08
  Speaker 1: a probe sampling conditions that nothing else can reach. And
• 31:13
  Speaker 1: those conditions are strange. Voyager crossed the heliopause in 2012,
• 31:20
  Speaker 1: the boundary where the Sun's influence ends and interstellar space begins.
• 31:25
  Speaker 1: Before that crossing, Instruments detected the solar wind, particles streaming
• 31:31
  Speaker 1: outward from our star. After the crossing, the readings changed.
• 31:37
  Speaker 1: Different particles, different magnetic field orientations. Evidence that Voyager had
• 31:44
  Speaker 1: entered a region shaped by forces from outside our solar system.
• 31:49
  Speaker 1: That transition wasn't sharp. The boundary between solar and interstellar
• 31:55
  Speaker 1: space turned out to be more like a turbulent coastline
• 31:58
  Speaker 1: than a clean edge. Voyager detected oscillations, variations, regions where
• 32:05
  Speaker 1: solar particles mixed with interstellar ones. The data revealed complexity
• 32:11
  Speaker 1: nobody had predicted. Scientists are still analysing those measurements, still
• 32:17
  Speaker 1: trying to understand what the readings mean. Because before Voyager,
• 32:23
  Speaker 1: we had no direct observations of interstellar space. We had
• 32:28
  Speaker 1: theories and models, but no actual data. Voyager provided the
• 32:34
  Speaker 1: first ground truth, the first measurements we could compare against predictions,
• 32:40
  Speaker 1: and the predictions weren't always correct. The magnetic field orientation
• 32:45
  Speaker 1: in interstellar space, for example, surprised researchers. Models suggested it
• 32:52
  Speaker 1: would point in one direction. Voyager's instruments showed it pointing differently.
• 32:58
  Speaker 1: That discrepancy forced scientists to revise their understanding of how
• 33:03
  Speaker 1: our solar system moves through the galaxy. The cosmic ray
• 33:07
  Speaker 1: measurements are equally important. Inside the heliosphere, the Sun's magnetic
• 33:14
  Speaker 1: field deflects many cosmic rays, preventing them from reaching the
• 33:19
  Speaker 1: inner solar system. Outside that protective bubble, cosmic ray intensity
• 33:25
  Speaker 1: increases dramatically. Voyager's instruments detect particles that have travelled across
• 33:32
  Speaker 1: the galaxy, carrying information about distant supernovae and the structure
• 33:38
  Speaker 1: of interstellar space itself. Every bit of data matters. Engineers
• 33:45
  Speaker 1: know this. They've spent decades optimizing how information gets packaged
• 33:50
  Speaker 1: and transmitted, choosing which measurements to send first, which data
• 33:56
  Speaker 1: can wait, how to compress readings without losing critical information.
• 34:02
  Speaker 1: It's a constant balancing act between scientific value and transmission capacity.
• 34:08
  Speaker 1: The plasma wave instrument provides some of the most intriguing data.
• 34:13
  Speaker 1: It detects oscillations in the surrounding plasma charged particles that
• 34:18
  Speaker 1: fill the space between stars. These waves carry signatures of
• 34:23
  Speaker 1: nearby objects and events. When Voyager's instruments detect certain frequencies,
• 34:30
  Speaker 1: scientists can infer things about the density and temperature of
• 34:33
  Speaker 1: the local environment. In 2012 and 2013, the plasma wave
• 34:39
  Speaker 1: instrument detected something unexpected. oscillations that suggested Voyager was passing
• 34:46
  Speaker 1: through a region of increased plasma density. Analysis revealed these
• 34:51
  Speaker 1: were pressure waves, disturbances propagating through interstellar space, possibly triggered
• 34:58
  Speaker 1: by solar activity or interactions with the galactic environment. Those
• 35:04
  Speaker 1: measurements continue. Every few months, engineers review the incoming data
• 35:09
  Speaker 1: and adjust which instruments get priority. They balance power consumption
• 35:14
  Speaker 1: against scientific return. Sometimes they shut down one instrument temporarily
• 35:20
  Speaker 1: to give another more resources. It's like conducting an orchestra
• 35:24
  Speaker 1: where half the musicians can only play for a few
• 35:27
  Speaker 1: hours before needing rest. The magnetometer keeps running almost constantly.
• 35:33
  Speaker 1: It draws relatively little power and provides crucial orientation information.
• 35:38
  Speaker 1: Voyager needs to know which direction it's pointing. both for
• 35:42
  Speaker 1: scientific measurements and for keeping its antenna aimed at Earth.
• 35:47
  Speaker 1: The magnetometer readings help maintain that alignment. But here's something
• 35:52
  Speaker 1: most people don't realise. Voyager is tumbling. Very slowly, but measurably.
• 36:00
  Speaker 1: The spacecraft has thrusters that can correct this rotation, but
• 36:05
  Speaker 1: using them consumes fuel and generates heat that affects sensitive instruments.
• 36:11
  Speaker 1: So engineers let the tumbling continue, compensating for it in
• 36:15
  Speaker 1: their calculations, rather than fighting it directly. This creates challenges
• 36:21
  Speaker 1: for data transmission. As Voyager rotates, its antenna sweeps past Earth.
• 36:28
  Speaker 1: During those sweeps, the signal strength peaks. Between sweeps, it drops.
• 36:35
  Speaker 1: Engineers have to time their commands carefully, sending them when
• 36:39
  Speaker 1: the spacecraft's orientation is most favorable. They track Voyager's rotation rate,
• 36:44
  Speaker 1: predict when the antenna will point toward Earth, and schedule
• 36:48
  Speaker 1: transmissions accordingly. The Deep Space Network handles this complexity seamlessly.
• 36:55
  Speaker 1: Computers monitor the signal strength in real time, adjusting receiver
• 37:00
  Speaker 1: settings to maintain lock on Voyager's transmission. When the signal
• 37:04
  Speaker 1: fades below a certain threshold, the system switches to more
• 37:08
  Speaker 1: sensitive detection modes. When it strengthens again, they optimize for
• 37:14
  Speaker 1: data rate instead of sensitivity. What's remarkable is how well
• 37:19
  Speaker 1: this system works, despite being designed in the 1970s. The
• 37:26
  Speaker 1: fundamental architecture hasn't changed. Three antenna complexes spaced around Earth.
• 37:35
  Speaker 1: each site equipped with massive dishes that can track spacecraft
• 37:39
  Speaker 1: across billions of miles. The same basic infrastructure that communicated
• 37:45
  Speaker 1: with Voyager during its Jupiter encounter still handles its interstellar transmissions.
• 37:51
  Speaker 1: Of course, the equipment has been upgraded. Modern receivers replaced
• 37:57
  Speaker 1: vacuum tube technology. Digital signal processing replaced analog circuits. Computer
• 38:04
  Speaker 1: systems that once filled entire rooms now fit in server racks.
• 38:09
  Speaker 1: But the core concept remains identical. Sensitive receivers, massive antennas,
• 38:16
  Speaker 1: and careful management of a resource that's always in short supply.
• 38:21
  Speaker 1: Because here's the constraint nobody talks about. The Deep Space
• 38:25
  Speaker 1: Network supports dozens of active missions. Mars rovers. Asteroid probes.
• 38:32
  Speaker 1: missions to Jupiter and Saturn, spacecraft studying the Sun. They're
• 38:38
  Speaker 1: all competing for antenna time, all needing to transmit their
• 38:43
  Speaker 1: data back to Earth. Voyager gets a few hours per day,
• 38:47
  Speaker 1: sometimes less. The scheduling system allocates time based on mission priorities,
• 38:53
  Speaker 1: scientific return, and operational requirements. Critical missions get more time,
• 39:00
  Speaker 1: routine operations get less, Voyager, despite its historic significance, often
• 39:07
  Speaker 1: finds itself waiting in queue behind missions with more immediate needs.
• 39:12
  Speaker 1: This means engineers can't continuously monitor the spacecraft. They schedule
• 39:18
  Speaker 1: contact windows, transmit commands during those windows and wait for responses.
• 39:25
  Speaker 1: Between windows, Voyager operates autonomously, following its programmed instructions, collecting data,
• 39:34
  Speaker 1: and storing it for later transmission. The data storage capacity
• 39:39
  Speaker 1: is minuscule by modern standards. Voyager can buffer a few
• 39:44
  Speaker 1: hours' worth of measurements before memory fills up. If it
• 39:49
  Speaker 1: doesn't transmit that data soon enough, new measurements overwrite old ones.
• 39:55
  Speaker 1: Engineers have to ensure regular contact windows to download stored
• 39:59
  Speaker 1: data before it's lost. They've gotten very good at predicting
• 40:04
  Speaker 1: how much data will accumulate between contacts. They know which
• 40:08
  Speaker 1: instruments generate the most information. They understand compression ratios and
• 40:14
  Speaker 1: transmission rates. They can calculate exactly when memory will fill
• 40:19
  Speaker 1: and schedule downloads accordingly. But unexpected events complicate these calculations.
• 40:25
  Speaker 1: A solar outburst might trigger additional plasma wave activity, generating
• 40:31
  Speaker 1: more data than predicted. A cosmic raystorm might increase particle counts,
• 40:37
  Speaker 1: filling buffers faster than expected. When this happens, engineers have
• 40:43
  Speaker 1: to scramble. requesting emergency antenna time, adjusting priorities, sometimes accepting
• 40:51
  Speaker 1: that some data will be lost. The November 2023 failure
• 40:55
  Speaker 1: made all of this impossible. Without readable telemetry, engineers couldn't
• 41:00
  Speaker 1: tell what data was being collected. They couldn't determine which
• 41:04
  Speaker 1: instruments were functioning. They couldn't even verify that commands were
• 41:09
  Speaker 1: being executed correctly. The spacecraft became a black box, receiving
• 41:15
  Speaker 1: instructions but providing no meaningful feedback. That's why the April
• 41:20
  Speaker 1: repair was so critical. Restoring engineering telemetry didn't just mean
• 41:25
  Speaker 1: seeing how the spacecraft was doing. It meant regaining the
• 41:29
  Speaker 1: ability to manage data collection, schedule instrument operations, and optimize
• 41:35
  Speaker 1: limited resources. Without that capability, Voyager might as well have
• 41:41
  Speaker 1: been lost completely. The repair also revealed something about the
• 41:46
  Speaker 1: spacecraft's architecture that most people overlook. Voyager has three separate computers,
• 41:53
  Speaker 1: each handling different functions. The flight data subsystem packages science
• 41:59
  Speaker 1: and engineering data. The command computer subsystem processes instructions from Earth.
• 42:07
  Speaker 1: The attitude and articulation control subsystem manages orientation and pointing.
• 42:14
  Speaker 1: These computers don't communicate directly. Instead, they share information through
• 42:20
  Speaker 1: a data bus, a shared pathway where each computer can
• 42:24
  Speaker 1: read messages left by the others. It's like a bulletin
• 42:29
  Speaker 1: board where different departments post updates and requests. The system
• 42:34
  Speaker 1: is simple, robust, and designed to keep functioning even if
• 42:39
  Speaker 1: one computer fails. When the FDS encountered memory corruption, it
• 42:45
  Speaker 1: couldn't package data properly. But the other computers continued operating normally.
• 42:52
  Speaker 1: The command computer still received instructions. The AACS still maintained pointing.
• 43:01
  Speaker 1: The spacecraft didn't crash or shut down. It just lost
• 43:06
  Speaker 1: its ability to speak coherently. This architectural separation is what
• 43:11
  Speaker 1: made the repair possible. Engineers could send commands to the
• 43:15
  Speaker 1: command computer, which would pass them to the FDS, even
• 43:20
  Speaker 1: though the FDS couldn't respond properly. They could try different
• 43:24
  Speaker 1: diagnostic sequences, probe different memory locations, and eventually extract that
• 43:31
  Speaker 1: crucial memory dump, all because the computers remained partially independent.
• 43:38
  Speaker 1: Modern spacecraft often use more integrated designs, where a single
• 43:43
  Speaker 1: powerful computer handles multiple functions. That approach offers advantages. Faster processing,
• 43:51
  Speaker 1: easier software updates, more efficient resource sharing. But it also
• 43:57
  Speaker 1: creates single points of failure. If that one computer fails,
• 44:02
  Speaker 1: the entire spacecraft might become inoperable. Voyager's distributed architecture primitive
• 44:08
  Speaker 1: by today's standards, provided resilience that more advanced designs might lack.
• 44:15
  Speaker 1: The redundancy, the separation of functions, the simple communication protocols,
• 44:22
  Speaker 1: all of these meant that partial failures didn't cascade into
• 44:26
  Speaker 1: total loss. Engineers designing current missions study Voyager's architecture carefully.
• 44:34
  Speaker 1: They're learning lessons about redundancy, about simplicity, about building systems
• 44:40
  Speaker 1: that can survive decades of operation in hostile environments. Some
• 44:46
  Speaker 1: of those lessons are being incorporated into new spacecraft. Others
• 44:51
  Speaker 1: are being set aside in favour of more capable but
• 44:55
  Speaker 1: less robust designs. It's a fundamental trade-off in engineering. Capability
• 45:02
  Speaker 1: versus reliability. Performance versus longevity. You can build something that
• 45:09
  Speaker 1: does everything perfectly under ideal conditions, or you can build
• 45:14
  Speaker 1: something that keeps working when conditions are terrible. Voyager represents
• 45:20
  Speaker 1: the latter philosophy, and that philosophy has kept it alive
• 45:25
  Speaker 1: for 47 years. The power situation deserves closer examination, because
• 45:32
  Speaker 1: it shapes every decision about Voyager's future. When engineers talk
• 45:37
  Speaker 1: about managing declining power, they're not describing some abstract technical challenge.
• 45:44
  Speaker 1: They're making choices about which parts of humanity's farthest messenger
• 45:48
  Speaker 1: get to keep functioning and which have to shut down forever.
• 45:52
  Speaker 1: Voyager's power comes from radioisotope thermoelectric generators, essentially nuclear batteries
• 45:59
  Speaker 1: that convert heat from decaying plutonium-238 into electricity. At launch
• 46:07
  Speaker 1: in 1977, Voyager 1's RTGs produced about 470 watts. That's
• 46:15
  Speaker 1: roughly the power consumption of a decent gaming computer. Nearly
• 46:20
  Speaker 1: 50 years later, as the plutonium continues its inexorable radioactive decay,
• 46:27
  Speaker 1: power output has dropped to around 220 watts. And it
• 46:32
  Speaker 1: keeps falling. losing approximately 4 watts every year. 4 watts
• 46:39
  Speaker 1: doesn't sound significant until you realise what it means in practice.
• 46:44
  Speaker 1: That's enough power to run a small LED bulb. Every year,
• 46:50
  Speaker 1: the equivalent of one bulb's worth of electricity vanishes from
• 46:54
  Speaker 1: the spacecraft's available budget. Engineers have to decide what gets
• 46:58
  Speaker 1: sacrificed to keep critical systems alive. The first casualties were
• 47:04
  Speaker 1: the heaters. Starting around 2019, engineers began shutting down heaters
• 47:11
  Speaker 1: that kept various components within their tested temperature ranges. The
• 47:16
  Speaker 1: scientific instruments were supposed to operate within specific thermal limits.
• 47:22
  Speaker 1: Going below those limits risked permanent damage or erratic behavior,
• 47:28
  Speaker 1: but keeping the heaters running meant less power for everything else.
• 47:33
  Speaker 1: So they made a calculated gamble. Shut off the heaters
• 47:38
  Speaker 1: and hope the instruments could handle the cold. They could.
• 47:42
  Speaker 1: Temperatures dropped well below design specifications. Some instruments now operate
• 47:48
  Speaker 1: at temperatures they were never tested at during ground development.
• 47:53
  Speaker 1: But they keep working. Why? Nobody knows for certain. Maybe
• 47:58
  Speaker 1: the original thermal requirements were overly conservative. Maybe the vacuum
• 48:04
  Speaker 1: of space provides better insulation than expected. Maybe it's just luck.
• 48:09
  Speaker 1: This pattern has repeated across multiple systems. Engineers identify something
• 48:16
  Speaker 1: that seems non-essential. They calculate the power savings. They transmit
• 48:21
  Speaker 1: the shutdown command and wait two days to see if
• 48:24
  Speaker 1: the spacecraft survives. Usually it does. Sometimes they discover surprising
• 48:30
  Speaker 1: consequences that force them to rethink their assumptions about how
• 48:35
  Speaker 1: systems interact. The attitude control thrusters present a particularly delicate challenge.
• 48:43
  Speaker 1: Voyager uses small thrusters to maintain its orientation, keeping its
• 48:49
  Speaker 1: antenna pointed precisely at Earth. As power declines, Running these
• 48:54
  Speaker 1: thrusters becomes progressively more expensive in terms of available electrical budget,
• 49:01
  Speaker 1: but without proper orientation, the spacecraft can't communicate. It's a
• 49:07
  Speaker 1: fundamental requirement that can't be compromised. In 2017, engineers faced
• 49:13
  Speaker 1: a thruster crisis. The primary attitude control thrusters had been
• 49:19
  Speaker 1: firing continually, since 1980, nearly 40 years of operation. They
• 49:25
  Speaker 1: were showing signs of degradation, requiring more heat and power
• 49:29
  Speaker 1: to produce the same thrust. If this trend continued, they'd
• 49:34
  Speaker 1: eventually fail completely. The solution was audacious. Voyager has backup
• 49:41
  Speaker 1: thrusters that hadn't been used since the Saturn encounter in 1980.
• 49:47
  Speaker 1: These trajectory correction maneuver thrusters were designed for a completely
• 49:51
  Speaker 1: different purpose, making large course adjustments during planetary flybys. But
• 49:59
  Speaker 1: they could theoretically handle attitude control if configured correctly. The problem?
• 50:05
  Speaker 1: Nobody knew if they'd still work after 37 years of dormancy.
• 50:10
  Speaker 1: The fuel lines might be clogged. The valves might be frozen.
• 50:15
  Speaker 1: The heaters might have failed. And if the test went wrong,
• 50:19
  Speaker 1: Voyager could tumble out of control, losing communication forever. They
• 50:25
  Speaker 1: did it anyway. On November 28th, 2017, engineers sent commands
• 50:32
  Speaker 1: to fire the backup thrusters for the first time in
• 50:35
  Speaker 1: nearly four decades. Then they waited the standard 45 hours
• 50:40
  Speaker 1: for confirmation. When the data came back, the thrusters had
• 50:46
  Speaker 1: fired perfectly. They switched over completely, buying potentially years of
• 50:52
  Speaker 1: additional operational life. This episode reveals something crucial about managing Voyager.
• 51:00
  Speaker 1: Every decision carries enormous risk because there's no possibility of
• 51:04
  Speaker 1: physical repair. You can't send a technician You can't install
• 51:08
  Speaker 1: replacement parts. You can't even directly observe what's happening. You
• 51:13
  Speaker 1: send commands into the void and hope they work. The
• 51:17
  Speaker 1: power budget also affects how much data Voyager can transmit.
• 51:22
  Speaker 1: Lower power means weaker signals. Weaker signals require longer integration
• 51:28
  Speaker 1: times at the receiving antennas to extract usable data. Longer
• 51:32
  Speaker 1: integration times mean lower data rates. Lower data rates mean
• 51:37
  Speaker 1: less science gets transmitted back to Earth. Currently, Voyager transmits
• 51:42
  Speaker 1: data at roughly 160 bits per second. That's slower than
• 51:48
  Speaker 1: the earliest dial-up modems from the 1970s. At this rate,
• 51:53
  Speaker 1: sending a single smartphone photo would take hours. But it's
• 51:58
  Speaker 1: sufficient for the spacecraft's current mission, measuring the plasma magnetic fields,
• 52:04
  Speaker 1: and particles in interstellar space. These measurements don't require high bandwidth.
• 52:11
  Speaker 1: They're simple readings that compress into small data packets. Still,
• 52:17
  Speaker 1: engineers constantly juggle priorities. Should they allocate power to the
• 52:22
  Speaker 1: plasma wave instrument or the magnetometer? Should they collect more
• 52:27
  Speaker 1: frequent measurements or extend the mission duration? by reducing sampling rates.
• 52:34
  Speaker 1: Every choice involves trade-offs between scientific return and operational longevity.
• 52:41
  Speaker 1: The science team has a wish list of measurements they'd
• 52:44
  Speaker 1: love to make if power were unlimited. They'd run all
• 52:48
  Speaker 1: instruments simultaneously at maximum sensitivity. They'd sample more frequently to
• 52:54
  Speaker 1: catch transient phenomena. They'd transmit redundant data for error checking.
• 53:00
  Speaker 1: But power limitations force brutal prioritization. What's the single most
• 53:06
  Speaker 1: important measurement right now? That's what gets power. This creates
• 53:11
  Speaker 1: an interesting dynamic, where Voyager's mission has evolved from intensive
• 53:16
  Speaker 1: planetary observation to sparse interstellar monitoring. During the Jupiter and
• 53:23
  Speaker 1: Saturn flybys, instruments ran continuously, cameras snapped photos every few seconds,
• 53:31
  Speaker 1: and data poured back to Earth at the maximum rate
• 53:34
  Speaker 1: the spacecraft could manage. Now, decades later, instruments cycle on
• 53:42
  Speaker 1: and off in carefully orchestrated sequences designed to maximize scientific
• 53:48
  Speaker 1: value while minimizing power consumption. The October 2024 incident that
• 53:54
  Speaker 1: triggered the fault protection system illustrates how fragile this balance
• 53:59
  Speaker 1: has become. Something caused an unexpected power draw, possibly a
• 54:04
  Speaker 1: cosmic ray hit, possibly a component briefly malfunctioning. The fault
• 54:10
  Speaker 1: protection system detected the anomaly and automatically switched to lower
• 54:15
  Speaker 1: power backup systems to prevent total failure. This autonomy is crucial.
• 54:21
  Speaker 1: With two-day communication delays, Voyager must be able to protect
• 54:26
  Speaker 1: itself when things go wrong. The onboard fault protection monitors
• 54:31
  Speaker 1: power levels, temperatures, and system status. If parameters exceed safe limits,
• 54:38
  Speaker 1: it takes defensive action without waiting for instructions from Earth.
• 54:43
  Speaker 1: It might shut down non-essential systems. It might switch to
• 54:48
  Speaker 1: backup hardware. It might reduce data transmission rates to conserve power.
• 54:54
  Speaker 1: These autonomous responses save the mission. But they also complicate
• 54:59
  Speaker 1: operations because engineers discover problems only after the spacecraft has
• 55:04
  Speaker 1: already reacted. They receive telemetry showing that Voyager switched to
• 55:10
  Speaker 1: the S-band transmitter three days ago. Now they have to
• 55:14
  Speaker 1: figure out why, determine if it's safe to switch back,
• 55:19
  Speaker 1: and craft commands to restore normal operations. all while working
• 55:24
  Speaker 1: through that 45-hour communication lag. The S-band transmitter incident is
• 55:30
  Speaker 1: worth examining in detail. This backup transmitter operates at a
• 55:35
  Speaker 1: lower frequency than the primary X-band transmitter. Lower frequency means
• 55:41
  Speaker 1: the signal can penetrate through various obstacles better, but it
• 55:46
  Speaker 1: also means the signal is even weaker when it reaches Earth.
• 55:51
  Speaker 1: About one-fifth the strength of the X-band signal. When Voyager
• 55:56
  Speaker 1: switched to S-band in October 2024, engineers at the Deep
• 56:01
  Speaker 1: Space Network faced a detection problem. The S-band signal was
• 56:06
  Speaker 1: so faint that standard reception techniques barely registered it. They
• 56:12
  Speaker 1: had to use specialised signal processing, longer integration times, and
• 56:18
  Speaker 1: creative filtering to extract the spacecraft's message from the cosmic
• 56:22
  Speaker 1: background noise. The fact that they succeeded demonstrates the extraordinary
• 56:27
  Speaker 1: sensitivity of the Deep Space Network antennas. These dishes can
• 56:33
  Speaker 1: detect signals carrying less power than a single snowflake hitting
• 56:37
  Speaker 1: the ground. They're listening for whispers from across the solar system,
• 56:42
  Speaker 1: pulling coherent data from electromagnetic noise that's billions of times
• 56:48
  Speaker 1: stronger than the signal itself. But even the most sensitive
• 56:52
  Speaker 1: antennas have limits. As Voyager's power continues declining, its signal
• 56:58
  Speaker 1: will keep getting weaker. Eventually, probably sometime in the 2030s,
• 57:06
  Speaker 1: the signal will drop below the detection threshold. The spacecraft
• 57:11
  Speaker 1: will still be functioning, still collecting data, still transmitting. But
• 57:17
  Speaker 1: Earth won't be able to hear it anymore. That inevitable
• 57:21
  Speaker 1: silence creates a strange situation. Voyager won't die in any
• 57:26
  Speaker 1: dramatic way. It'll just fade beyond our ability to communicate
• 57:31
  Speaker 1: with it. The spacecraft will continue operating on its remaining power,
• 57:36
  Speaker 1: executing whatever final commands were uploaded until the RTGs decay
• 57:41
  Speaker 1: below the minimum voltage required to run any systems at all.
• 57:46
  Speaker 1: Even then, Voyager won't stop existing. it'll just become inert,
• 57:53
  Speaker 1: a silent artifact tumbling through interstellar space, carrying its golden
• 57:59
  Speaker 1: record with greetings in 55 languages, music from across human cultures,
• 58:05
  Speaker 1: and images showing what Earth and its inhabitants look like.
• 58:09
  Speaker 1: Current projections suggest that by 2036, there won't be enough
• 58:14
  Speaker 1: power to operate even a single scientific instrument. By that point,
• 58:20
  Speaker 1: Engineers might be able to receive basic engineering telemetry, enough
• 58:24
  Speaker 1: to know the spacecraft is still alive, but not enough
• 58:28
  Speaker 1: to collect science data. A few years after that, there
• 58:33
  Speaker 1: won't be enough power to run the transmitter at all.
• 58:36
  Speaker 1: These projections assume steady decay and no catastrophic failures. But
• 58:42
  Speaker 1: Voyager has already exceeded expectations so thoroughly that making confident
• 58:47
  Speaker 1: predictions feels presumptuous. Components that should have failed years ago
• 58:52
  Speaker 1: keep working. Systems operating outside their design parameters continue functioning.
• 59:00
  Speaker 1: The spacecraft demonstrates a resilience that its designers probably hoped for,
• 59:05
  Speaker 1: but couldn't guarantee. This resilience comes partly from over-engineering, building
• 59:13
  Speaker 1: systems with safety margins that could accommodate decades of degradation,
• 59:19
  Speaker 1: but it also comes from something harder to quantify. The
• 59:24
  Speaker 1: original engineers made thousands of small decisions about component selection,
• 59:30
  Speaker 1: circuit design, and system architecture. Many of those decisions were
• 59:35
  Speaker 1: guided by intuition and experience rather than formal requirements. They
• 59:41
  Speaker 1: chose parts that felt robust. They added redundancy where it
• 59:46
  Speaker 1: seemed prudent. They designed systems to fail gracefully rather than catastrophically.
• 59:54
  Speaker 1: Those accumulated choices created a spacecraft that could survive 47
• 59:59
  Speaker 1: years in space. Not because anyone explicitly designed it to
• 1:00:05
  Speaker 1: last that long, the mission was supposed to end after
• 1:00:08
  Speaker 1: five years, but because the foundational engineering philosophy emphasized durability
• 1:00:16
  Speaker 1: over cutting-edge performance. Modern spacecraft design often goes the other way.
• 1:00:24
  Speaker 1: Engineers optimize for capability, accepting reduced reliability to achieve higher performance.
• 1:00:32
  Speaker 1: They use state-of-the-art components that offer incredible functionality, but might
• 1:00:37
  Speaker 1: not survive decades of operation. They minimize mass and power consumption,
• 1:00:44
  Speaker 1: which means less margin for degradation. This approach makes sense
• 1:00:50
  Speaker 1: for missions with defined timelines. If your spacecraft only needs
• 1:00:54
  Speaker 1: to function for five years, designing it to survive 50
• 1:00:59
  Speaker 1: is wasteful. You're carrying extra mass that reduces your scientific payload.
• 1:01:04
  Speaker 1: You're using outdated components when newer technology could provide better results.
• 1:01:12
  Speaker 1: You're spending money on redundancy you'll probably never need. But
• 1:01:16
  Speaker 1: Voyager's extended lifetime demonstrates the value of that conservative approach.
• 1:01:21
  Speaker 1: The mission has returned science for 47 years because the
• 1:01:25
  Speaker 1: spacecraft was built to withstand anything space could throw at it.
• 1:01:30
  Speaker 1: And it's still working. The Deep Space Network handles that
• 1:01:35
  Speaker 1: eventual silence in a way that's both practical and melancholic.
• 1:01:41
  Speaker 1: As Voyager's signal weakens, DSN engineers... will gradually allocate more
• 1:01:47
  Speaker 1: antenna time to the spacecraft, shifting from shared observation windows
• 1:01:53
  Speaker 1: to dedicated tracking sessions. They'll combine signals from multiple antennas
• 1:02:00
  Speaker 1: to boost reception sensitivity. They'll adjust data rates downward, trading
• 1:02:07
  Speaker 1: information quantity for signal reliability. But there's a hard limit
• 1:02:11
  Speaker 1: to what even the most sensitive receivers can detect. Radio
• 1:02:17
  Speaker 1: signals obey inverse square law. They weaken proportionally to the
• 1:02:22
  Speaker 1: square of the distance, double the distance, and you need
• 1:02:26
  Speaker 1: four times the antenna sensitivity to maintain the same signal quality.
• 1:02:33
  Speaker 1: At Voyager's current distance, the signal arriving at Earth carries
• 1:02:37
  Speaker 1: less power than it takes to illuminate a single pixel
• 1:02:41
  Speaker 1: on a digital watch display. As that distance continues growing,
• 1:02:46
  Speaker 1: The signal will eventually drop below what's called the noise floor,
• 1:02:51
  Speaker 1: the background electromagnetic hiss that permeates space. When that happens,
• 1:02:57
  Speaker 1: no amount of antenna combining or signal processing will recover
• 1:03:02
  Speaker 1: Voyager's transmissions. The information will still be there, encoded in
• 1:03:07
  Speaker 1: radio waves spreading outward from the spacecraft. But it'll be
• 1:03:12
  Speaker 1: buried so deep in background noise, that extracting it becomes
• 1:03:16
  Speaker 1: mathematically impossible. Engineers know roughly when this threshold will arrive.
• 1:03:23
  Speaker 1: Current projections suggest that by 2036, Voyager won't have enough
• 1:03:28
  Speaker 1: power to operate scientific instruments. A few years later, it
• 1:03:34
  Speaker 1: might manage basic engineering telemetry, simple status reports indicating the
• 1:03:39
  Speaker 1: spacecraft is still functioning. Probably by the late 2030s or
• 1:03:46
  Speaker 1: early 2040s, the transmitter will shut down entirely. These projections
• 1:03:52
  Speaker 1: carry significant uncertainty. They assume steady degradation and no catastrophic failures.
• 1:04:00
  Speaker 1: They assume the RTGs continue producing power at predicted rates.
• 1:04:06
  Speaker 1: They assume no major component breakdowns beyond what engineers can
• 1:04:10
  Speaker 1: work around remotely. any of those assumptions could prove wrong.
• 1:04:16
  Speaker 1: What engineers can't predict is whether Voyager will experience a sudden,
• 1:04:21
  Speaker 1: catastrophic failure that ends the mission abruptly, or whether it'll
• 1:04:26
  Speaker 1: gradually fade as systems shut down one by one. The
• 1:04:30
  Speaker 1: spacecraft has already demonstrated remarkable resilience through decades of operation,
• 1:04:36
  Speaker 1: in conditions that weren't fully understood when it launched. Components
• 1:04:41
  Speaker 1: have survived temperature extremes, radiation doses, and mechanical stresses that
• 1:04:47
  Speaker 1: exceeded their design specifications. That resilience comes partly from the
• 1:04:53
  Speaker 1: conservative engineering approach used in the 1970s. Designers selected components
• 1:05:00
  Speaker 1: with large safety margins. They included redundant systems wherever mass
• 1:05:06
  Speaker 1: budgets allowed. They chose proven technology over cutting-edge capabilities. This
• 1:05:14
  Speaker 1: philosophy created a spacecraft that could absorb decades of degradation
• 1:05:19
  Speaker 1: while continuing to function. But it also comes from luck.
• 1:05:25
  Speaker 1: The specific trajectory Voyager followed, the particular radiation environment it encountered,
• 1:05:32
  Speaker 1: the thermal cycling it experienced, all of these factors affected
• 1:05:38
  Speaker 1: component reliability in ways that couldn't be fully predicted. A
• 1:05:43
  Speaker 1: slightly different path might have exposed critical systems to radiation
• 1:05:47
  Speaker 1: levels that would have caused failures years ago, or it
• 1:05:52
  Speaker 1: might have avoided radiation altogether, allowing the spacecraft to operate
• 1:05:56
  Speaker 1: even longer than current projections suggest. The November 2023 computer
• 1:06:02
  Speaker 1: failure demonstrates both aspects of Voyager's situation. The failure itself,
• 1:06:08
  Speaker 1: a single memory chip in the flight data subsystem, represented
• 1:06:13
  Speaker 1: the kind of gradual degradation that engineers expected would eventually
• 1:06:18
  Speaker 1: affect the spacecraft. After 46 years of continuous operation in
• 1:06:23
  Speaker 1: the harsh space environment, it's surprising that more components haven't failed.
• 1:06:29
  Speaker 1: But the nature of the failure also revealed how much
• 1:06:32
  Speaker 1: margin remained in the systems. Engineers could work around the
• 1:06:36
  Speaker 1: failed chip by relocating code to other memory locations. They
• 1:06:42
  Speaker 1: could delete obsolete routines designed for planetary encounters that ended
• 1:06:47
  Speaker 1: decades ago. They could optimize and compress the remaining code
• 1:06:52
  Speaker 1: to fit within the available space. The spacecraft had enough
• 1:06:58
  Speaker 1: functional resources left to absorb this failure and continue operating.
• 1:07:04
  Speaker 1: That repair process itself showcased the extraordinary capabilities of the
• 1:07:10
  Speaker 1: Deep Space Network. When Voyager sent back that initial corrupted
• 1:07:15
  Speaker 1: signal in November 2023, that repeating pattern of ones and zeros,
• 1:07:22
  Speaker 1: DSN engineers had to decode a transmission format they'd never
• 1:07:26
  Speaker 1: seen before. The spacecraft was trying to communicate, but not
• 1:07:30
  Speaker 1: in its normal language. One DSN engineer spent hours analyzing
• 1:07:36
  Speaker 1: the signal pattern, comparing it against documentation of the FDS architecture,
• 1:07:43
  Speaker 1: looking for recognizable structures in what appeared to be random noise. Eventually,
• 1:07:49
  Speaker 1: they identified it as a memory dump, a complete readout
• 1:07:53
  Speaker 1: of the FDS memory, transmitted in a format that bypassed
• 1:07:58
  Speaker 1: the normal data packaging routines. This kind of detective work
• 1:08:03
  Speaker 1: requires both deep technical knowledge and creative problem solving. The
• 1:08:10
  Speaker 1: engineer needed to understand 1970s computer architecture, data formatting conventions
• 1:08:16
  Speaker 1: from that era, and how the FDS organized its memory.
• 1:08:21
  Speaker 1: They also needed to recognize that the gibberish signal might
• 1:08:25
  Speaker 1: actually contain structured information encoded in an unexpected way. Once decoded,
• 1:08:33
  Speaker 1: that memory dump became the key to diagnosing the failure.
• 1:08:38
  Speaker 1: By comparing the actual memory contents against how the system
• 1:08:43
  Speaker 1: should be structured, engineers could identify exactly which section of
• 1:08:48
  Speaker 1: memory had failed, and what code resided there. This allowed
• 1:08:53
  Speaker 1: them to develop the repair strategy, relocating that code to
• 1:08:58
  Speaker 1: other memory locations. Implementing that repair required another set of challenges.
• 1:09:06
  Speaker 1: Engineers had to divide the affected code into sections small
• 1:09:10
  Speaker 1: enough to fit in available memory spaces scattered throughout the FDS.
• 1:09:16
  Speaker 1: They had to modify each section so it could function
• 1:09:20
  Speaker 1: in its new location. They had to update all references
• 1:09:24
  Speaker 1: to that code elsewhere in the system, and they had
• 1:09:27
  Speaker 1: to do all of this using documentation from the 1970s,
• 1:09:32
  Speaker 1: much of it on yellowed paper or old mimeographs. Several
• 1:09:38
  Speaker 1: of the original Voyager engineers had retired or passed away,
• 1:09:42
  Speaker 1: the current team was essentially archaeological detectives, piecing together design
• 1:09:47
  Speaker 1: decisions made nearly 50 years ago by people who never
• 1:09:51
  Speaker 1: imagined the spacecraft would still be operating in 2024. Why
• 1:09:56
  Speaker 1: did they structure the memory this way? Why did they
• 1:10:00
  Speaker 1: choose this particular data format? What assumptions were they making
• 1:10:06
  Speaker 1: about how the system would be used? These questions mattered
• 1:10:11
  Speaker 1: because any modification had to respect the original architecture. The
• 1:10:17
  Speaker 1: engineers couldn't simply rewrite the FDS software from scratch. They
• 1:10:22
  Speaker 1: were working with a system that had been optimized for
• 1:10:26
  Speaker 1: 1970s hardware constraints and couldn't be fundamentally restructured. They had
• 1:10:32
  Speaker 1: to work within the framework the original designers created. making
• 1:10:37
  Speaker 1: minimal changes that preserved the system's overall logic. The repair
• 1:10:44
  Speaker 1: process took five months from when the failure first occurred
• 1:10:48
  Speaker 1: in November 2023 to when science operations fully resumed in
• 1:10:54
  Speaker 1: June 2024. During that time, Voyager was essentially in a coma,
• 1:11:01
  Speaker 1: alive but unable to communicate meaningful information. Engineers sent commands
• 1:11:07
  Speaker 1: and waited two days for responses, trying different diagnostic approaches,
• 1:11:13
  Speaker 1: analyzing the results, formulating new hypotheses. When the fix finally
• 1:11:18
  Speaker 1: worked on April 20th, 2024, the relief at JPL was palpable.
• 1:11:26
  Speaker 1: For the first time in five months, they could see
• 1:11:29
  Speaker 1: the spacecraft's health status. They could verify that all systems
• 1:11:34
  Speaker 1: were functioning normally. They could confirm that no other problems
• 1:11:39
  Speaker 1: had developed during the months of troubleshooting. But that was
• 1:11:43
  Speaker 1: just the first phase. Engineering telemetry was flowing again, but
• 1:11:49
  Speaker 1: the scientific instruments remained silent. Over the following weeks, engineers
• 1:11:56
  Speaker 1: repeated the repair process for the code that handled science data.
• 1:12:01
  Speaker 1: They relocated those routines to new memory locations, tested them,
• 1:12:06
  Speaker 1: and gradually brought the instruments back online. By June, all
• 1:12:11
  Speaker 1: four science instruments were operational again. The magnetometer resumed measuring
• 1:12:17
  Speaker 1: the interstellar magnetic field. The plasma wave instrument continued detecting
• 1:12:23
  Speaker 1: electron oscillations in the surrounding plasma. The cosmic ray detector
• 1:12:29
  Speaker 1: went back to counting high-energy particles. The low-energy charged particle
• 1:12:35
  Speaker 1: instrument returned to monitoring the distribution of ions and electrons.
• 1:12:40
  Speaker 1: This repair demonstrated something remarkable about the human capacity to
• 1:12:45
  Speaker 1: solve problems across vast distances and timescales. The spacecraft is
• 1:12:51
  Speaker 1: more than 15 billion miles away. Signals take 45 hours
• 1:12:56
  Speaker 1: for a round trip. The computer system being repaired was
• 1:13:01
  Speaker 1: designed half a century ago. using technology that's now obsolete.
• 1:13:07
  Speaker 1: The original engineers are mostly gone. The documentation is fragmentary
• 1:13:13
  Speaker 1: and aging. Yet despite all these obstacles, engineers managed to
• 1:13:18
  Speaker 1: diagnose a complex computer failure, develop a repair strategy, implement
• 1:13:24
  Speaker 1: it successfully, and restore full functionality. They did it using patience, creativity,
• 1:13:31
  Speaker 1: and deep technical knowledge. They did it by thinking through
• 1:13:36
  Speaker 1: the original designer's logic and finding ways to work within
• 1:13:40
  Speaker 1: constraints that would seem impossibly restrictive to modern software engineers.
• 1:13:46
  Speaker 1: The success of this repair raises questions about how long
• 1:13:50
  Speaker 1: engineers can continue solving Voyager's problems remotely. Each failure removes
• 1:13:56
  Speaker 1: some margin from the system, Each workaround uses resources that
• 1:14:02
  Speaker 1: can't be replaced. The spacecraft is gradually consuming its own redundancy,
• 1:14:08
  Speaker 1: converting backup capabilities into primary systems to compensate for components
• 1:14:14
  Speaker 1: that fail. Eventually, a failure will occur that can't be
• 1:14:18
  Speaker 1: worked around. Maybe it'll be another memory chip in a
• 1:14:22
  Speaker 1: location where code can't be relocated. Maybe it'll be a
• 1:14:26
  Speaker 1: critical component in the transmitter or receiver that prevents communication entirely.
• 1:14:33
  Speaker 1: Maybe it'll be a power system failure that shuts down
• 1:14:36
  Speaker 1: multiple systems simultaneously. When that happens, the mission will effectively end,
• 1:14:43
  Speaker 1: even if the spacecraft continues functioning. Without communication, there's no
• 1:14:48
  Speaker 1: way to receive data or send new commands. Voyager will
• 1:14:52
  Speaker 1: execute whatever final instructions were uploaded and then continue operating
• 1:14:57
  Speaker 1: autonomously until its power supply decays below minimum operating levels.
• 1:15:04
  Speaker 1: The team knows this is coming. They're already planning for it,
• 1:15:09
  Speaker 1: deciding which final commands to send, which systems to prioritise
• 1:15:14
  Speaker 1: in the remaining operational years, how to maximise the scientific
• 1:15:19
  Speaker 1: return from whatever time remains. They're documenting everything about the
• 1:15:25
  Speaker 1: spacecraft's current state, so that future generations might understand what
• 1:15:30
  Speaker 1: happened after communication ceased. Because even after contact ends, Voyager
• 1:15:37
  Speaker 1: will continue existing. It'll keep travelling outward at 38,000 miles
• 1:15:42
  Speaker 1: per hour, adding another billion miles to its distance every
• 1:15:47
  Speaker 1: seven years. In about 40,000 years, it'll make its closest
• 1:15:52
  Speaker 1: approach to another star, passing within about one and a
• 1:15:56
  Speaker 1: half light years of Gliese 445 in the constellation Camelopardalis.
• 1:16:03
  Speaker 1: By then, Voyager will be a completely inert artifact. No power,
• 1:16:09
  Speaker 1: no active systems, just a metal structure carrying its golden record,
• 1:16:15
  Speaker 1: still moving through the void. The spacecraft will continue that
• 1:16:19
  Speaker 1: journey for billions of years, long after Earth itself has
• 1:16:23
  Speaker 1: changed beyond recognition, carrying humanity's message to whatever might eventually
• 1:16:29
  Speaker 1: find it. The Deep Space Network isn't just impressive because
• 1:16:34
  Speaker 1: of its antenna size, it's the sensitivity that matters. These
• 1:16:40
  Speaker 1: dishes can detect signals arriving with less power than what's
• 1:16:44
  Speaker 1: needed to run a digital watch, a billionth of a
• 1:16:48
  Speaker 1: billionth of a watt. That's what Voyager's signal delivers when
• 1:16:53
  Speaker 1: it reaches Earth, a whisper so faint it barely exists
• 1:16:58
  Speaker 1: above the cosmic background noise. Three complexes form the network. Goldstone,
• 1:17:05
  Speaker 1: in California's Mojave Desert. Madrid, in the mountains northwest of
• 1:17:10
  Speaker 1: Spain's capital. Canberra, in Australia's outback. They're positioned roughly 120
• 1:17:16
  Speaker 1: degrees apart in longitude. which means as Earth rotates and
• 1:17:23
  Speaker 1: one complex loses sight of Voyager below the horizon, another
• 1:17:28
  Speaker 1: is already bringing it into view. Continuous coverage, 24 hours
• 1:17:35
  Speaker 1: a day, every single day. Each complex operates multiple antennas.
• 1:17:42
  Speaker 1: The largest dishes measure 70 meters across. That's 230 feet
• 1:17:47
  Speaker 1: of precisely curved metal surface. These massive structures can tilt
• 1:17:53
  Speaker 1: and rotate to track spacecraft across the sky with extraordinary precision.
• 1:17:59
  Speaker 1: They're so sensitive that they can detect the thermal radiation
• 1:18:03
  Speaker 1: from distant planets, measure the wobble in a spacecraft's trajectory
• 1:18:08
  Speaker 1: caused by gravitational anomalies, and pick out Voyager's feeble signal
• 1:18:14
  Speaker 1: from trillions of miles away. When that strange garbled signal
• 1:18:18
  Speaker 1: came back from Voyager in March, after the poke command,
• 1:18:22
  Speaker 1: it wasn't in the expected format. The spacecraft was trying
• 1:18:27
  Speaker 1: to communicate something, but the message was scrambled. An engineer
• 1:18:32
  Speaker 1: at the Deep Space Network decoded it anyway, pulling meaning
• 1:18:36
  Speaker 1: from chaos through technical expertise and creative interpretation. That decoded
• 1:18:43
  Speaker 1: signal contained the complete memory readout that revealed the failed chip.
• 1:18:48
  Speaker 1: Without the deep space network, this repair would have been impossible.
• 1:18:54
  Speaker 1: You need that sensitivity to hear the spacecraft. You need
• 1:18:58
  Speaker 1: that global coverage to maintain constant contact. You need that
• 1:19:03
  Speaker 1: technical expertise to interpret unexpected signals. The network, is humanity's
• 1:19:10
  Speaker 1: lifeline to its most distant explorers. But here's what makes
• 1:19:14
  Speaker 1: this even more challenging. Voyager's distance keeps increasing. Every second,
• 1:19:21
  Speaker 1: it travels another 11 miles farther from Earth. Every day,
• 1:19:26
  Speaker 1: another million miles. Every year, another 360 million miles. The
• 1:19:33
  Speaker 1: signal gets weaker. The round-trip communication time gets longer. In
• 1:19:38
  Speaker 1: November 2026, Voyager will reach one light day from Earth.
• 1:19:45
  Speaker 1: That's the distance light travels in 24 hours, roughly 16
• 1:19:49
  Speaker 1: billion miles. At that point, if an engineer sends a
• 1:19:54
  Speaker 1: command on Monday morning, the response won't arrive until Wednesday morning.
• 1:19:59
  Speaker 1: Two full days for a round trip. Every diagnostic test.
• 1:20:05
  Speaker 1: Every repair attempt. every software patch, all requiring minimum 48
• 1:20:11
  Speaker 1: hour cycles. This creates a fundamental constraint on how the
• 1:20:15
  Speaker 1: mission operates. You can't troubleshoot in real time. You can't
• 1:20:20
  Speaker 1: try something, see if it works, and immediately adjust your approach.
• 1:20:26
  Speaker 1: Every decision requires careful planning. Every command needs thorough testing
• 1:20:32
  Speaker 1: and review before transmission. A mistake could make things worse,
• 1:20:37
  Speaker 1: or permanently disable the spacecraft. The October incident demonstrated this perfectly.
• 1:20:45
  Speaker 1: On October 16th, Voyager experienced another problem. Three days later,
• 1:20:51
  Speaker 1: it fell completely silent. The team suspected the fault protection
• 1:20:57
  Speaker 1: system had triggered again, switching off the main X-band transmitter
• 1:21:02
  Speaker 1: to conserve power. But which backup system had it switched to?
• 1:21:08
  Speaker 1: The spacecraft hadn't used its S-band transmitter since 1981, over
• 1:21:14
  Speaker 1: 40 years ago. That transmitter operates at much lower frequency
• 1:21:19
  Speaker 1: than the X-band, which means the signal is even fainter
• 1:21:23
  Speaker 1: when it reaches Earth. Finding that signal was like searching
• 1:21:28
  Speaker 1: for a candle flame from across an entire continent. But
• 1:21:32
  Speaker 1: the Deep Space Network found it anyway. Engineers reactivated the
• 1:21:37
  Speaker 1: X-band transmitter and resumed normal operations by early November. Crisis averted.
• 1:21:45
  Speaker 1: But each incident consumes resources. Each workaround reduces future options.
• 1:21:52
  Speaker 1: The spacecraft is gradually using up its redundancy, converting backup
• 1:21:57
  Speaker 1: systems into primary systems to compensate for failures. Power is
• 1:22:02
  Speaker 1: the ultimate limiting factor. Voyager's radioisotope thermoelectric generators convert heat
• 1:22:08
  Speaker 1: from decaying plutonium-238 into electricity. When the spacecraft launched in 1977,
• 1:22:16
  Speaker 1: those generators produced 470 watts. Nearly 50 years later, the
• 1:22:23
  Speaker 1: output has declined dramatically. The spacecraft loses about 4 watts
• 1:22:28
  Speaker 1: every year as the plutonium continues decaying. Four watts doesn't
• 1:22:33
  Speaker 1: sound like much, but when your total available power keeps shrinking,
• 1:22:39
  Speaker 1: every watt becomes precious. Engineers have been managing this decline
• 1:22:44
  Speaker 1: for decades, making careful decisions about which systems to keep
• 1:22:49
  Speaker 1: running and which to shut down. About five years ago,
• 1:22:54
  Speaker 1: they began turning off heaters for some science instruments. The
• 1:22:59
  Speaker 1: instruments were designed to operate within specific temperature ranges, and
• 1:23:04
  Speaker 1: letting them get colder meant risking permanent damage. But the
• 1:23:09
  Speaker 1: team had no choice. They needed to conserve power for
• 1:23:14
  Speaker 1: critical systems. Surprisingly, all the instruments continued functioning despite reaching
• 1:23:21
  Speaker 1: temperatures far below their tested limits. the hardware proved more
• 1:23:27
  Speaker 1: resilient than its specifications suggested. Earlier this year, the team
• 1:23:31
  Speaker 1: had to shut down a science instrument on Voyager 2
• 1:23:35
  Speaker 1: to conserve power. Each shutdown is a loss. Data that
• 1:23:40
  Speaker 1: will never be collected. Measurements that will never be made.
• 1:23:44
  Speaker 1: But it's necessary to extend the mission's operational lifetime. Current
• 1:23:50
  Speaker 1: estimates suggest the spacecraft might maintain enough power to return
• 1:23:54
  Speaker 1: engineering data until 2036. Science operations will end sooner, probably
• 1:24:02
  Speaker 1: by the early 2030s, when there won't be enough power
• 1:24:06
  Speaker 1: to run even one instrument. After that, Voyager will still exist,
• 1:24:12
  Speaker 1: still function, but it won't be able to tell us
• 1:24:15
  Speaker 1: what it's experiencing. The spacecraft has surprised engineers before. Systems
• 1:24:22
  Speaker 1: have operated at temperatures well below their rated limits. Components
• 1:24:27
  Speaker 1: have lasted decades beyond their design life. The entire mission
• 1:24:32
  Speaker 1: has exceeded every expectation. But physics imposes hard limits. Radioactive
• 1:24:38
  Speaker 1: decay follows an inexorable curve. Eventually, the power output will
• 1:24:44
  Speaker 1: drop below the minimum needed. to maintain communication. When that happens,
• 1:24:50
  Speaker 1: the mission effectively ends, even if the spacecraft remains functional.
• 1:24:56
  Speaker 1: Without power for the transmitter, there's no way to receive data.
• 1:25:02
  Speaker 1: Without power for the receiver, there's no way to send
• 1:25:05
  Speaker 1: new commands. Voyager will execute whatever final instructions were uploaded
• 1:25:11
  Speaker 1: and then continue operating autonomously until its systems shut down
• 1:25:16
  Speaker 1: one by one. The team is already planning for this.
• 1:25:20
  Speaker 1: They're deciding which final commands to send, which systems to prioritize,
• 1:25:27
  Speaker 1: how to maximize scientific return from the remaining operational time.
• 1:25:33
  Speaker 1: They're documenting everything about the spacecraft's current state, creating a
• 1:25:38
  Speaker 1: detailed record for future generations, who might want to understand
• 1:25:43
  Speaker 1: what happened after communications ceased. This isn't the first time
• 1:25:48
  Speaker 1: Voyager has faced serious technical problems. In May 2022, the
• 1:25:54
  Speaker 1: attitude articulation and control system started sending nonsensical data. Engineers
• 1:26:01
  Speaker 1: fixed it by routing the telemetry through a different computer.
• 1:26:05
  Speaker 1: In December 2023, the flight data system failed. leading to
• 1:26:11
  Speaker 1: the five-month repair effort. Both Voyagers lost portions of their
• 1:26:16
  Speaker 1: memory during the Prime mission decades ago, and they've experienced
• 1:26:21
  Speaker 1: numerous unexplained anomalies over the years. Each problem required creative
• 1:26:26
  Speaker 1: solutions tailored to the specific failure and the spacecraft's limitations.
• 1:26:32
  Speaker 1: The fact that engineers have repeatedly found workarounds speaks to
• 1:26:36
  Speaker 1: both the robust original designs and the ingenuity of the
• 1:26:41
  Speaker 1: support teams. But it also reveals something about the nature
• 1:26:45
  Speaker 1: of these repairs. They're not fixing the underlying problems. They're
• 1:26:51
  Speaker 1: working around them, using redundant systems, relocating code, routing signals
• 1:26:59
  Speaker 1: through alternate paths. Every workaround consumes some resource that can't
• 1:27:04
  Speaker 1: be replaced. Every repair uses up margins. The spacecraft is
• 1:27:10
  Speaker 1: gradually depleting its own resilience, converting backup capabilities into primary
• 1:27:15
  Speaker 1: functions to compensate for failures. Eventually, a failure will occur
• 1:27:21
  Speaker 1: that has no work around. Maybe it'll be another memory
• 1:27:26
  Speaker 1: chip in a location where code can't be relocated. Maybe
• 1:27:30
  Speaker 1: it'll be a critical transmitter component that prevents all communication.
• 1:27:36
  Speaker 1: Maybe it'll be multiple simultaneous failures that overwhelm the engineer's
• 1:27:40
  Speaker 1: ability to respond. The increasing distance makes every future repair
• 1:27:46
  Speaker 1: more difficult. As Voyager moves farther away, the round-trip communication
• 1:27:52
  Speaker 1: time grows longer. Diagnostic cycles take more time. Testing solutions
• 1:27:59
  Speaker 1: requires more patience. The engineering team must think even more
• 1:28:03
  Speaker 1: carefully before sending each command. In some ways, maintaining Voyager
• 1:28:10
  Speaker 1: is like caring for an aging patient with a chronic condition.
• 1:28:14
  Speaker 1: You manage symptoms. You work around limitations. You make difficult
• 1:28:20
  Speaker 1: triage decisions about which functions to preserve and which to
• 1:28:24
  Speaker 1: let go. You know that eventually, despite your best efforts,
• 1:28:29
  Speaker 1: The decline will continue until something critical fails. But unlike
• 1:28:35
  Speaker 1: a patient, Voyager won't simply cease to exist when communication fails. ends.
• 1:28:41
  Speaker 1: The spacecraft will continue its journey, a silent traveller moving
• 1:28:46
  Speaker 1: through interstellar space at 38,000 miles per hour. It'll keep
• 1:28:52
  Speaker 1: adding distance, keep moving away from the solar system, keep
• 1:28:57
  Speaker 1: carrying humanity's message encoded on its golden record. In about 40,000 years,
• 1:29:04
  Speaker 1: Voyager will make its closest approach to another star, passing
• 1:29:08
  Speaker 1: within roughly one and a half light years of Gliese
• 1:29:13
  Speaker 1: 445 in the constellation Camelopardalis. By then, the spacecraft will
• 1:29:19
  Speaker 1: be completely inert. No power, no active systems, just a
• 1:29:25
  Speaker 1: metal structure with gold-plated records attached, still moving through the
• 1:29:30
  Speaker 1: void at the same velocity it has now. The spacecraft
• 1:29:34
  Speaker 1: will continue that journey for billions of years, long after
• 1:29:39
  Speaker 1: Earth's continents have shifted beyond recognition, long after the Sun
• 1:29:44
  Speaker 1: has exhausted its hydrogen and begun swelling into a red giant,
• 1:29:49
  Speaker 1: long after human civilization has either spread to the stars
• 1:29:54
  Speaker 1: or vanished entirely. Voyager will still be out there, a
• 1:29:59
  Speaker 1: testament to what humans achieved in the late 20th century.
• 1:30:04
  Speaker 1: That's the strange duality of this mission. In one sense,
• 1:30:08
  Speaker 1: it's ending soon. Power is declining. Systems are failing. Communication
• 1:30:14
  Speaker 1: will cease within a decade or two. But in another sense,
• 1:30:19
  Speaker 1: the mission is just beginning its longest phase, An eternal
• 1:30:23
  Speaker 1: journey through interstellar space that will outlast everything that created it.
• 1:30:29
  Speaker 1: The engineers managing Voyager understand this. They know their work
• 1:30:33
  Speaker 1: has a finite timeline. They know that someday soon, probably
• 1:30:38
  Speaker 1: within their own careers, they'll send the last command and
• 1:30:41
  Speaker 1: receive the last signal. After that, Voyager will be beyond
• 1:30:46
  Speaker 1: human reach. an autonomous artifact carrying our message to whatever
• 1:30:51
  Speaker 1: might eventually find it. Until then, they'll keep monitoring every signal,
• 1:30:57
  Speaker 1: analyzing every data packet, watching the slow decline of power
• 1:31:03
  Speaker 1: and the gradual failure of systems. They'll make the choices
• 1:31:07
  Speaker 1: that need to be made, which instruments to shut down,
• 1:31:11
  Speaker 1: which heaters to turn off. which redundant systems to sacrifice
• 1:31:16
  Speaker 1: to keep essential functions running just a little longer. The
• 1:31:21
  Speaker 1: relationship between these engineers and Voyager has become something more
• 1:31:25
  Speaker 1: than technical stewardship. It's personal in a way that's difficult
• 1:31:30
  Speaker 1: to articulate. They're maintaining humanity's connection to a spacecraft that's
• 1:31:35
  Speaker 1: becoming less and less like a machine, and more like
• 1:31:39
  Speaker 1: an ambassador. A representative of our species, carrying a message
• 1:31:45
  Speaker 1: that might outlast our civilization by billions of years. That message,
• 1:31:52
  Speaker 1: the golden record attached to each voyager, contains sounds and
• 1:31:57
  Speaker 1: images selected to portray the diversity of life and culture
• 1:32:01
  Speaker 1: on Earth, music from different cultures and eras, greetings in
• 1:32:06
  Speaker 1: 55 languages, sounds of wind and rain, birds and whales,
• 1:32:11
  Speaker 1: a mother's kiss and a beating heart. Images of humans, animals, landscapes,
• 1:32:18
  Speaker 1: architecture and scientific diagrams. The record was designed to be
• 1:32:23
  Speaker 1: playable by any technologically advanced civilization that might encounter it.
• 1:32:28
  Speaker 1: Instructions for playing it are etched on the cover in
• 1:32:32
  Speaker 1: what scientists hoped would be a universal language, physics and mathematics.
• 1:32:38
  Speaker 1: The hydrogen atom's characteristic wavelength. Binary notation. pulsar locations to
• 1:32:46
  Speaker 1: identify our solar system's position in the galaxy. Carl Sagan
• 1:32:51
  Speaker 1: and his team spent months selecting the contents, debating what
• 1:32:55
  Speaker 1: would best represent humanity to an alien intelligence. What music
• 1:33:01
  Speaker 1: captures the essence of human creativity? What images convey who
• 1:33:07
  Speaker 1: we are? What message should we send to beings we
• 1:33:12
  Speaker 1: might never meet? The Golden Record transforms Voyager from a
• 1:33:17
  Speaker 1: scientific instrument into something more profound, a time capsule and
• 1:33:22
  Speaker 1: message in a bottle combined. Even if every system fails,
• 1:33:27
  Speaker 1: even if the spacecraft becomes completely inert, it'll still carry
• 1:33:32
  Speaker 1: that record, still represent us to whatever might find it,
• 1:33:38
  Speaker 1: and the odds of anything finding it are vanishingly small.
• 1:33:42
  Speaker 1: space is incomprehensibly vast. Voyager's path doesn't take it particularly
• 1:33:49
  Speaker 1: close to any known stars for tens of thousands of years.
• 1:33:53
  Speaker 1: By the time it approaches another stellar system, that system's
• 1:33:57
  Speaker 1: planets will have moved. The chance of any civilization detecting
• 1:34:02
  Speaker 1: and retrieving this small, silent object drifting through the void
• 1:34:08
  Speaker 1: is almost zero. But almost zero isn't zero, and that
• 1:34:13
  Speaker 1: infinitesimal possibility gives the mission a significance that transcends its
• 1:34:19
  Speaker 1: scientific achievements. Voyager represents humanity's first attempt to send something
• 1:34:26
  Speaker 1: beyond our solar system that might survive long enough to
• 1:34:30
  Speaker 1: be found by another intelligence. The engineers maintaining Voyager understand
• 1:34:35
  Speaker 1: this dual nature of their work, On one level, they're
• 1:34:39
  Speaker 1: troubleshooting a failing spacecraft, relocating code, managing power budgets, working
• 1:34:46
  Speaker 1: around broken systems. On another level, they're preserving humanity's connection
• 1:34:52
  Speaker 1: to our most distant creation, for as long as physics allows.
• 1:34:57
  Speaker 1: Each successful repair buys more time. Not just for science, though.
• 1:35:04
  Speaker 1: The data Voyager continues to collect about interstellar space remains valuable,
• 1:35:10
  Speaker 1: but time for humanity to maintain that connection, to know
• 1:35:15
  Speaker 1: that something we built is out there, still functioning, still exploring,
• 1:35:21
  Speaker 1: still representing us in the cosmic void. The 2024 repair
• 1:35:27
  Speaker 1: was particularly significant because it demonstrated that even with decades-old technology,
• 1:35:33
  Speaker 1: With systems operating far beyond their design specifications, with components
• 1:35:39
  Speaker 1: failing in unpredictable ways, human ingenuity could still find solutions.
• 1:35:46
  Speaker 1: The engineers took a spacecraft with 68 kilobytes of memory,
• 1:35:51
  Speaker 1: less than a single modern text message, and performed the
• 1:35:55
  Speaker 1: equivalent of brain surgery across 15 billion miles using 45-hour
• 1:36:01
  Speaker 1: communication delays. They did this by understanding not just how
• 1:36:07
  Speaker 1: the systems work, but how the original designers thought. By
• 1:36:12
  Speaker 1: reading yellow documents and faded mimeographs. By reconstructing the logic
• 1:36:18
  Speaker 1: and intentions of engineers who built these systems before personal
• 1:36:22
  Speaker 1: computers existed, before the internet, before most of the modern world.
• 1:36:28
  Speaker 1: That connection across generations. Current engineers channeling the thinking of
• 1:36:34
  Speaker 1: designers from the 1970s mirrors the larger connection Voyager represents.
• 1:36:42
  Speaker 1: A link between different eras of humanity, different levels of technology,
• 1:36:48
  Speaker 1: different perspectives on our place in the universe. When Voyager
• 1:36:53
  Speaker 1: launched in 1977, the Cold War was at its peak.
• 1:36:59
  Speaker 1: the world seemed divided into permanent ideological blocks. The idea
• 1:37:04
  Speaker 1: that humanity might speak with one voice to the cosmos
• 1:37:08
  Speaker 1: seemed almost naive. Yet the Golden Record attempted exactly that,
• 1:37:13
  Speaker 1: to represent Earth as a unified whole, rather than a
• 1:37:17
  Speaker 1: collection of competing nations. Nearly 50 years later, the world
• 1:37:22
  Speaker 1: has changed in ways the Voyager team couldn't have predicted.
• 1:37:26
  Speaker 1: The Soviet Union no longer exists. The internet has connected
• 1:37:31
  Speaker 1: humanity in unprecedented ways, while simultaneously revealing new divisions. Climate
• 1:37:39
  Speaker 1: change has emerged as an existential threat. Private companies are
• 1:37:44
  Speaker 1: launching rockets that would have seemed like science fiction in 1977.
• 1:37:50
  Speaker 1: But Voyager keeps going, its trajectory determined decades ago. its
• 1:37:56
  Speaker 1: message unchanged, its function as humanity's representative, unaffected by political
• 1:38:03
  Speaker 1: shifts or technological revolutions or cultural changes. That persistence carries
• 1:38:09
  Speaker 1: its own message. The spacecraft demonstrates that some human achievements
• 1:38:15
  Speaker 1: transcend the moment of their creation. That engineering excellence and
• 1:38:20
  Speaker 1: scientific curiosity can produce something that outlasts its creators and
• 1:38:26
  Speaker 1: their entire civilization. The engineers know their time with Voyager
• 1:38:32
  Speaker 1: is limited. They can see the power curves declining. They
• 1:38:37
  Speaker 1: can project when critical systems will fail. They know roughly
• 1:38:42
  Speaker 1: when communication will become impossible, probably within the next decade.
• 1:38:48
  Speaker 1: almost certainly before 2036. But they also know they're part
• 1:38:54
  Speaker 1: of something larger than maintaining a spacecraft. They're extending humanity's
• 1:39:00
  Speaker 1: presence in the cosmos for as long as possible. They're
• 1:39:04
  Speaker 1: ensuring that when Voyager finally falls silent, it'll be because
• 1:39:09
  Speaker 1: physics made continued operation impossible. not because human error or
• 1:39:15
  Speaker 1: insufficient effort allowed preventable failures. The October 2024 communication hiccup,
• 1:39:23
  Speaker 1: when Voyager switched to its backup S-band transmitter, demonstrated both
• 1:39:28
  Speaker 1: the spacecraft's autonomous resilience and the increasing fragility of the mission.
• 1:39:34
  Speaker 1: The fault protection system worked exactly as designed, protecting critical
• 1:39:40
  Speaker 1: systems by switching to lower power mode without waiting for
• 1:39:44
  Speaker 1: instructions from Earth. But it also showed how thin the
• 1:39:49
  Speaker 1: margins have become. The Deep Space Network had to detect
• 1:39:54
  Speaker 1: an extremely weak signal using a transmitter that hadn't been
• 1:40:00
  Speaker 1: used since 1981. If they hadn't found that signal, if
• 1:40:06
  Speaker 1: the S-band had failed, or if the DSN couldn't detect it,
• 1:40:11
  Speaker 1: The spacecraft might have been lost permanently despite still functioning.
• 1:40:17
  Speaker 1: These close calls will become more frequent. Each system operates
• 1:40:21
  Speaker 1: closer to its failure point. Each repair consumes more margin.
• 1:40:26
  Speaker 1: Each workaround uses up resources that can't be replaced. The
• 1:40:31
  Speaker 1: engineers prepare for each scenario they can imagine. They develop
• 1:40:35
  Speaker 1: contingency plans. They identify which systems can be sacrificed and
• 1:40:41
  Speaker 1: in what order. They map out the sequence of graceful
• 1:40:45
  Speaker 1: degradation that'll extend operations as long as possible, but they
• 1:40:49
  Speaker 1: also know that eventually, something will happen they can't fix.
• 1:40:54
  Speaker 1: Some failure will occur that has no workaround. Some combination
• 1:40:59
  Speaker 1: of problems will overwhelm their ability to respond. Or the
• 1:41:03
  Speaker 1: power will simply decline to the point where no configuration
• 1:41:08
  Speaker 1: can maintain communication. When that day comes, they'll send a
• 1:41:14
  Speaker 1: final command. Maybe it'll be instructions for the spacecraft to
• 1:41:19
  Speaker 1: continue collecting data, even though it can't transmit anymore. Information
• 1:41:26
  Speaker 1: stored in memory that no one will ever retrieve, but
• 1:41:30
  Speaker 1: collected anyway, because that's what Voyager does. Maybe it'll be
• 1:41:36
  Speaker 1: a final systems check. maybe just an acknowledgement that this
• 1:41:41
  Speaker 1: is the end of communication. And then Voyager will be
• 1:41:45
  Speaker 1: on its own, truly alone in a way it hasn't
• 1:41:48
  Speaker 1: been since launch. No more commands from Earth, no more
• 1:41:52
  Speaker 1: course corrections, no more repairs or workarounds or careful management
• 1:41:57
  Speaker 1: of declining resources. Just a silent traveller moving through interstellar
• 1:42:02
  Speaker 1: space at 38,000 miles per hour. carrying its golden message
• 1:42:08
  Speaker 1: to whatever might eventually find it. The spacecraft will continue
• 1:42:13
  Speaker 1: adding distance for billions of years. It'll pass through regions
• 1:42:18
  Speaker 1: of space humans haven't named and will never see. It'll
• 1:42:22
  Speaker 1: witness cosmic events, supernovas, stellar collisions, planetary formations that no
• 1:42:29
  Speaker 1: human instrument will ever detect. It'll outlast not just the
• 1:42:34
  Speaker 1: engineers who maintain it, and the scientists who built it,
• 1:42:39
  Speaker 1: but the entire species that created it. That's the strange
• 1:42:43
  Speaker 1: mathematics of interstellar travel. The mission's operational phase, the part
• 1:42:50
  Speaker 1: where humans control and communicate with Voyager, represents less than
• 1:42:55
  Speaker 1: one millionth of one percent of the spacecraft's total journey.
• 1:43:00
  Speaker 1: The vast majority of Voyager's existence will be spent silent
• 1:43:04
  Speaker 1: and autonomous. long after humanity is gone. The engineers understand this.
• 1:43:12
  Speaker 1: They know they're managing the brief opening chapter of a
• 1:43:15
  Speaker 1: story that'll continue for billions of years. They know the
• 1:43:20
  Speaker 1: real mission, carrying humanity's message through the galaxy, has barely
• 1:43:25
  Speaker 1: begun and will continue long after they're gone. So they
• 1:43:30
  Speaker 1: keep working, keep troubleshooting, keep finding solutions to problems that
• 1:43:36
  Speaker 1: seemed unsolvable. Keep extending operations one more day, one more month,
• 1:43:43
  Speaker 1: one more year. Not because they believe Voyager will run forever,
• 1:43:47
  Speaker 1: but because every additional day of operation is a gift.
• 1:43:52
  Speaker 1: Every new piece of data from interstellar space is valuable.
• 1:43:57
  Speaker 1: Every moment of continued communication is precious. And when the
• 1:44:02
  Speaker 1: final signal comes... When Voyager sends its last data packet
• 1:44:07
  Speaker 1: and falls permanently silent, they'll know they did everything possible.
• 1:44:14
  Speaker 1: That they extended humanity's reach into the cosmos as far
• 1:44:17
  Speaker 1: as physics and engineering would allow. That they gave Voyager
• 1:44:23
  Speaker 1: every possible chance to complete its mission. The spacecraft will
• 1:44:28
  Speaker 1: continue its journey regardless, moving through the void at the
• 1:44:33
  Speaker 1: same speed. carrying the same message, representing humanity to the cosmos,
• 1:44:40
  Speaker 1: whether we're there to monitor its progress or not. That
• 1:44:44
  Speaker 1: journey is Voyager's true mission. Not the data it collects
• 1:44:49
  Speaker 1: or the systems it operates, but the simple fact of
• 1:44:53
  Speaker 1: its existence as humanity's first attempt to touch the stars.
• 1:44:58
  Speaker 1: That's the real legacy of the April 2024 repair. Not
• 1:45:03
  Speaker 1: that engineers fixed a computer from 15 billion miles away,
• 1:45:08
  Speaker 1: though that achievement stands on its own. The legacy is
• 1:45:12
  Speaker 1: what that repair represents about human persistence in the face
• 1:45:16
  Speaker 1: of impossible odds. Think about what actually happened. A single
• 1:45:23
  Speaker 1: memory chip failed in a computer built in the 1970s.
• 1:45:28
  Speaker 1: That chip contained code critical to the spacecraft's ability to communicate.
• 1:45:35
  Speaker 1: The engineers couldn't see the failure directly, couldn't touch the hardware,
• 1:45:41
  Speaker 1: couldn't run standard diagnostics. Every command they sent took 45
• 1:45:47
  Speaker 1: hours for a round-trip response. They had to work with
• 1:45:51
  Speaker 1: documentation from nearly 50 years ago. Yellowed papers and fading
• 1:45:57
  Speaker 1: mimeographs written by people who never imagined the spacecraft would
• 1:46:02
  Speaker 1: still be operating in 2024. Many of those original engineers
• 1:46:08
  Speaker 1: had retired or died. The current team was essentially doing archaeology,
• 1:46:14
  Speaker 1: reconstructing the thinking of designers from a different era. And
• 1:46:18
  Speaker 1: they succeeded. They decoded a garbled signal that turned out
• 1:46:23
  Speaker 1: to be a complete memory dump. They identified the exact
• 1:46:27
  Speaker 1: chip that had failed. They devised a solution that required
• 1:46:32
  Speaker 1: splitting code into sections and distributing those sections across different
• 1:46:37
  Speaker 1: memory locations. They modified each section to work in its
• 1:46:42
  Speaker 1: new home. They updated every reference throughout the system. Then
• 1:46:48
  Speaker 1: they transmitted the fix and waited two days to see
• 1:46:51
  Speaker 1: if it worked. When the response came back on April 20th, 2024,
• 1:46:59
  Speaker 1: Voyager was talking again after five months of silence. But
• 1:47:03
  Speaker 1: here's what makes this story different from typical engineering achievements.
• 1:47:08
  Speaker 1: This wasn't about building something new or pushing technology to
• 1:47:12
  Speaker 1: its limits. This was about keeping something alive that should
• 1:47:16
  Speaker 1: have died decades ago. about refusing to give up on
• 1:47:20
  Speaker 1: a machine that's already exceeded every reasonable expectation. Voyager was
• 1:47:26
  Speaker 1: designed for a five-year mission. It's been operating for 47 years.
• 1:47:32
  Speaker 1: It's travelled farther than any human-made object in history. It's
• 1:47:37
  Speaker 1: sent back data from realms no other instrument can reach.
• 1:47:42
  Speaker 1: And it's still working. That continued operation isn't luck. It's
• 1:47:47
  Speaker 1: the result of thousands of decisions made by hundreds of
• 1:47:51
  Speaker 1: people over nearly five decades. Engineers who built in redundancy
• 1:47:57
  Speaker 1: they didn't strictly need. Scientists who chose robust components over
• 1:48:02
  Speaker 1: cutting-edge performance. Mission planners who prepared for contingencies they couldn't
• 1:48:09
  Speaker 1: fully predict. And now, decades later, engineers who spend their
• 1:48:16
  Speaker 1: careers maintaining a spacecraft that's older than most of them are. are,
• 1:48:21
  Speaker 1: who pore over documentation from before they were born, who
• 1:48:26
  Speaker 1: develop creative solutions to problems that shouldn't be solvable with
• 1:48:31
  Speaker 1: 1970s technology. Each repair buys a little more time, Each
• 1:48:37
  Speaker 1: workaround extends operations a few more months or years. But
• 1:48:41
  Speaker 1: the ultimate outcome is inevitable. Power continues declining. Systems continue failing.
• 1:48:50
  Speaker 1: Distance continues increasing. Eventually, communication will end. Current projections suggest
• 1:48:58
  Speaker 1: science operations will cease by the early 2030s. Engineering telemetry
• 1:49:04
  Speaker 1: might continue until 2036 or so. then silence. Not because
• 1:49:11
  Speaker 1: the spacecraft stops working, but because it won't have enough
• 1:49:15
  Speaker 1: power to run its transmitter. When that day comes, Voyager
• 1:49:20
  Speaker 1: will execute whatever final commands were uploaded and continue operating autonomously.
• 1:49:28
  Speaker 1: It'll keep collecting data that no one will receive, keep
• 1:49:32
  Speaker 1: following its programming until the power supply decays below minimum
• 1:49:38
  Speaker 1: operating levels. Then it'll become completely inert, a silent artifact
• 1:49:44
  Speaker 1: tumbling through interstellar space. But even then, the mission continues.
• 1:49:50
  Speaker 1: Because Voyager's ultimate purpose isn't collecting data or testing systems
• 1:49:56
  Speaker 1: or demonstrating technology, it's carrying humanity's message to whatever might
• 1:50:01
  Speaker 1: eventually find it. The golden record attached to the spacecraft
• 1:50:06
  Speaker 1: contains sounds and images from Earth, music from different cultures,
• 1:50:12
  Speaker 1: greetings in 55 languages, pictures of humans and animals and landscapes,
• 1:50:19
  Speaker 1: instructions for playing the record etched on its cover in
• 1:50:23
  Speaker 1: what scientists hoped would be a universal language of physics
• 1:50:27
  Speaker 1: and mathematics. That record transforms Voyager from a scientific instrument
• 1:50:33
  Speaker 1: into something more profound. An ambassador, a time capsule, a
• 1:50:39
  Speaker 1: message in a bottle thrown into the cosmic ocean. The
• 1:50:43
  Speaker 1: odds of anything finding it are vanishingly small. Space is
• 1:50:48
  Speaker 1: incomprehensibly vast. Voyager's trajectory doesn't take it particularly close to
• 1:50:54
  Speaker 1: any known stars for tens of thousands of years. By
• 1:50:58
  Speaker 1: the time it approaches another stellar system, the planets will
• 1:51:02
  Speaker 1: have moved. The chance of detection is almost zero. But
• 1:51:07
  Speaker 1: almost zero isn't zero. And that infinitesimal possibility gives the
• 1:51:13
  Speaker 1: mission significance that transcends its scientific achievements. Voyager represents humanity's
• 1:51:21
  Speaker 1: first attempt to send something beyond our solar system that
• 1:51:25
  Speaker 1: might survive long enough to be found by another intelligence.
• 1:51:29
  Speaker 1: In about 40,000 years, Voyager will pass within one and
• 1:51:34
  Speaker 1: a half light years of Gliese 445. By then, the
• 1:51:40
  Speaker 1: spacecraft will be completely dead. No power, no active systems,
• 1:51:46
  Speaker 1: just metal and silicon and gold, still moving through the
• 1:51:50
  Speaker 1: void at 38,000 miles per hour. It'll continue that journey
• 1:51:55
  Speaker 1: for billions of years, long after the engineers who maintain
• 1:51:59
  Speaker 1: it are gone, long after everyone alive today is forgotten,
• 1:52:04
  Speaker 1: long after human civilization has either spread to the stars
• 1:52:09
  Speaker 1: or vanished entirely. The spacecraft will outlast the continents, outlast
• 1:52:14
  Speaker 1: the oceans, probably outlast the Earth itself. When the sun
• 1:52:20
  Speaker 1: swells into a red giant five billion years from now
• 1:52:24
  Speaker 1: and consumes the inner planets, Voyager will still be out there,
• 1:52:29
  Speaker 1: moving through interstellar space, carrying its golden message. That's the
• 1:52:34
  Speaker 1: strange mathematics of this mission. The operational phase, the part
• 1:52:40
  Speaker 1: where humans control and communicate with Voyager, represents less than
• 1:52:45
  Speaker 1: one millionth of one percent of the spacecraft's total existence.
• 1:52:51
  Speaker 1: Everything we've done, all the planetary encounters and scientific discoveries
• 1:52:56
  Speaker 1: and engineering repairs, all of it is just the opening
• 1:53:00
  Speaker 1: moments of a story that will continue for billions of years.
• 1:53:05
  Speaker 1: The vast majority of Voyager's journey will happen in silence.
• 1:53:10
  Speaker 1: After we lose contact, after the spacecraft becomes inert, after
• 1:53:15
  Speaker 1: humanity is gone. Just a piece of 1970s technology drifting
• 1:53:21
  Speaker 1: through the galaxy, outlasting its creators by eons. The engineers
• 1:53:26
  Speaker 1: who repaired Voyager in 2024 understand this. They know their
• 1:53:32
  Speaker 1: work extends something that's already lasted far longer than anyone expected.
• 1:53:38
  Speaker 1: They know communication will end soon, probably within their own careers.
• 1:53:44
  Speaker 1: They know the real mission, the one that will continue
• 1:53:47
  Speaker 1: for billions of years, has barely begun. So they keep working,
• 1:53:54
  Speaker 1: keep troubleshooting, keep finding solutions to problems that seemed impossible.
• 1:54:00
  Speaker 1: Not because they believe Voyager will run forever, but because
• 1:54:04
  Speaker 1: every additional day of operation is valuable. Every new measurement
• 1:54:10
  Speaker 1: from interstellar space matters. Every moment of continued communication is precious.
• 1:54:17
  Speaker 1: When the final signal comes, when Voyager sends its last
• 1:54:21
  Speaker 1: data packet and falls permanently silent, they'll know they did
• 1:54:26
  Speaker 1: everything possible. That they extended humanity's reach as far as
• 1:54:30
  Speaker 1: physics and engineering would allow. That they gave Voyager every
• 1:54:35
  Speaker 1: chance to complete its mission. And the spacecraft will continue
• 1:54:39
  Speaker 1: its journey regardless, moving at the same speed, carrying the
• 1:54:45
  Speaker 1: same message, representing humanity to the cosmos, whether we're there
• 1:54:50
  Speaker 1: to monitor it or not. That's what the 2024 repair
• 1:54:55
  Speaker 1: really accomplished. Not just fixing a computer, or restoring communication,
• 1:55:01
  Speaker 1: or enabling continued science operations, though those achievements matter. What
• 1:55:08
  Speaker 1: it accomplished was extending our connection to humanity's most distant
• 1:55:13
  Speaker 1: ambassador for a little while longer. keeping alive, for a
• 1:55:18
  Speaker 1: few more years, our link to something that will eventually
• 1:55:22
  Speaker 1: become the longest lasting testament to human civilization. Because long
• 1:55:28
  Speaker 1: after everything else we've built has crumbled to dust, long
• 1:55:33
  Speaker 1: after our cities and monuments and records have vanished, Voyager
• 1:55:38
  Speaker 1: will still be out there, still carrying its golden message,
• 1:55:43
  Speaker 1: still representing us to the universe. A spacecraft repaired from
• 1:55:48
  Speaker 1: 15 billion miles away, kept alive by engineers who refuse
• 1:55:53
  Speaker 1: to give up, carrying humanity's message to the stars. That's
• 1:55:58
  Speaker 1: not just an engineering achievement. That's something else entirely. Something
• 1:56:04
  Speaker 1: that touches on what it means to be human. Our curiosity.
• 1:56:09
  Speaker 1: Our persistence. Our need to reach beyond ourselves into the unknown. Voyager.
• 1:56:16
  Speaker 1: will keep going. And someday, billions of years from now,
• 1:56:22
  Speaker 1: something might find it. Might decode the golden record. Might
• 1:56:27
  Speaker 1: learn that once, on a small planet orbiting an ordinary star,
• 1:56:31
  Speaker 1: there existed a species that built this machine and sent
• 1:56:35
  Speaker 1: it into the darkness. That looked up at the stars
• 1:56:39
  Speaker 1: and wondered. That refused to accept the boundaries of their world.
• 1:56:44
  Speaker 1: That's the real message Voyager carries. Not the sounds or
• 1:56:48
  Speaker 1: images on the Golden Record, but the simple fact of
• 1:56:52
  Speaker 1: its existence. That we were here. That we tried. That
• 1:56:58
  Speaker 1: we reached as far as we could into the cosmos,
• 1:57:02
  Speaker 1: knowing we'd never see the end of the journey. The
• 1:57:05
  Speaker 1: engineers who maintain Voyager aren't just keeping a spacecraft alive.
• 1:57:10
  Speaker 1: They're extending humanity's presence in the universe for as long
• 1:57:14
  Speaker 1: as physics allows. And when they finally send that last command,
• 1:57:19
  Speaker 1: when Voyager falls silent and begins its eternal autonomous journey,
• 1:57:24
  Speaker 1: they'll have succeeded in something remarkable. They'll have kept our
• 1:57:29
  Speaker 1: most distant ambassador talking for nearly 50 years. They'll have
• 1:57:34
  Speaker 1: extracted every possible moment of operation from a machine that
• 1:57:38
  Speaker 1: should have died decades ago. They'll have demonstrated that human
• 1:57:42
  Speaker 1: ingenuity can solve problems across billions of miles and half
• 1:57:47
  Speaker 1: a century of technological change. And Voyager will continue. Silent,
• 1:57:53
  Speaker 1: but still moving. Inert, but still carrying our message. A
• 1:57:59
  Speaker 1: testament to what humans achieved in the late 20th century,
• 1:58:03
  Speaker 1: travelling through the galaxy long after we're gone. 15 billion
• 1:58:08
  Speaker 1: miles away, and getting farther every second, still working, still exploring,
• 1:58:16
  Speaker 1: still representing us to whatever lies beyond.