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The backup engine oscillation started a six-hour clock for rescue · Space Exploration Stories

• 0:03
  Speaker 1: A laminated photograph of a family, sits in the dust
• 0:07
  Speaker 1: of the Descartes Highlands right now. It has been there
• 0:10
  Speaker 1: since April 21st, 1972. No spacecraft has returned to retrieve it.
• 0:16
  Speaker 1: No mission ever will, at least not yet. The crew
• 0:19
  Speaker 1: that left it behind traveled 238,000 miles to answer one
• 0:24
  Speaker 1: of the most carefully constructed questions in the history of
• 0:27
  Speaker 1: planetary science. They found the answer. It was the wrong answer.
• 0:32
  Speaker 1: and the six hours that separated the theory from the
• 0:34
  Speaker 1: wreckage of it were set in motion not by the moon,
• 0:37
  Speaker 1: but by a single oscillation in a backup engine system
• 0:41
  Speaker 1: that nobody expected. That is what this story is really about,
• 0:45
  Speaker 1: not just a lunar landing. A clock that started ticking
• 0:48
  Speaker 1: on flight day five, and did not stop until it
• 0:50
  Speaker 1: had consumed an experiment stranded a satellite, and forced three
• 0:55
  Speaker 1: men to carry home proof that the scientific consensus was
• 0:58
  Speaker 1: entirely mistaken. There is something about the photograph detail that
• 1:02
  Speaker 1: resists easy explanation. A plastic laminated portrait of Charles Duke's
• 1:06
  Speaker 1: wife and two young sons, signed on the back, placed
• 1:10
  Speaker 1: deliberately in the gray regolith. Duke left it there knowing
• 1:13
  Speaker 1: full well it would outlast every institution that sent him.
• 1:16
  Speaker 1: It is still there. The Descartes Highlands do not weather.
• 1:20
  Speaker 1: There is no wind, no rain, no decay. The photograph
• 1:24
  Speaker 1: is as intact today as the moment he set it down,
• 1:28
  Speaker 1: And yet, everything the mission was designed to confirm had
• 1:31
  Speaker 1: already begun to fall apart hours before Duke ever stepped
• 1:35
  Speaker 1: onto the surface. The scientific case for sending Apollo 16
• 1:39
  Speaker 1: to the Descartes Highlands was not casual. Geologist Dan Milton
• 1:44
  Speaker 1: and a broad coalition of planetary scientists had spent years
• 1:49
  Speaker 1: studying high-resolution orbital photographs of the region. The highlands were bright,
• 1:55
  Speaker 1: unusually bright. In the early 1970s, that brightness was understood
• 1:59
  Speaker 1: as a signature of volcanic rock, specifically of silica-rich material
• 2:04
  Speaker 1: that forms when magma erupts onto a surface and cools rapidly.
• 2:08
  Speaker 1: Two geological formations dominated the target area. The Cayley Formation,
• 2:13
  Speaker 1: a relatively smooth plains unit, and the Descartes Formation, a rougher,
• 2:18
  Speaker 1: hilly terrain. Both were interpreted as products of ancient volcanic activity.
• 2:23
  Speaker 1: The scientific consensus built on the best Earth analogs available,
• 2:28
  Speaker 1: pointed clearly in one direction. Apollo 16 would return volcanic
• 2:33
  Speaker 1: samples and rewrite the timeline of lunar volcanism. John Young,
• 2:37
  Speaker 1: 41 years old and on his fourth spaceflight, was assigned
• 2:41
  Speaker 1: as commander. He had already orbited the moon on Apollo 10,
• 2:45
  Speaker 1: close enough to see the landing sites, but not authorized
• 2:48
  Speaker 1: to touch down. He was methodical, experienced, and deeply skeptical
• 2:53
  Speaker 1: by temperament. a trait that would serve the mission in
• 2:57
  Speaker 1: unexpected ways. Thomas Kenneth Mattingly, 36, was the command module pilot.
• 3:04
  Speaker 1: Mattingly's history with Apollo was already unusual before the mission began.
• 3:09
  Speaker 1: Three days before the launch of Apollo 16, in April 1970,
• 3:14
  Speaker 1: he had been pulled from the crew. A child in
• 3:17
  Speaker 1: Charles Duke's family had developed rubella. Mattingly had been exposed.
• 3:23
  Speaker 1: Mission rules required his removal as a precaution. He watched
• 3:26
  Speaker 1: from the ground as Apollo 16's oxygen tank ruptured as
• 3:30
  Speaker 1: the crew improvised a survival plan across 200,000 miles of vacuum.
• 3:34
  Speaker 1: As Jack swiggered, his replacement helped keep three men alive.
• 3:39
  Speaker 1: Mattingly never got sick. Not one symptom. Now, two years later,
• 3:44
  Speaker 1: he was on the same crew as Duke. That specific combination.
• 3:48
  Speaker 1: The man removed because of Duke's household now flying with
• 3:52
  Speaker 1: Duke carried a weight that neither of them spoke about
• 3:55
  Speaker 1: publicly in clinical terms. But Mattingly had spent those two
• 3:59
  Speaker 1: years watching, studying, preparing. When Apollo 16 launched on April 16, 1972,
• 4:07
  Speaker 1: at 1254 in the afternoon Eastern Time, from Kennedy Space Center,
• 4:12
  Speaker 1: aboard Saturn V AS511, Mattingly was exactly where he had
• 4:17
  Speaker 1: been told he would never go. Charles Duke, also 36,
• 4:21
  Speaker 1: was on his first spaceflight. He was the youngest human
• 4:24
  Speaker 1: being to walk on the moon at the time of
• 4:26
  Speaker 1: the mission, a record he still holds. He was not
• 4:30
  Speaker 1: unknown to lunar history. During Apollo 11's powered descent on
• 4:34
  Speaker 1: July 20th, 1969, Duke had been the KP, the voice
• 4:40
  Speaker 1: from mission control that Neil Armstrong and Buzz Aldrin heard
• 4:44
  Speaker 1: as they approached the surface. His voice was the last
• 4:47
  Speaker 1: human voice they heard before touchdown. Now he would touch
• 4:51
  Speaker 1: the surface himself. His family portrait was packed in his
• 4:55
  Speaker 1: personal kit. The plan was straightforward by Apollo standards. Mattingly
• 5:00
  Speaker 1: would remain in the command module. Call sign Casper. Named
• 5:04
  Speaker 1: after Casper, the friendly ghost, Mattingly's choice. Young and Duke
• 5:09
  Speaker 1: would descend in the lunar module. Call sign Orion. They
• 5:12
  Speaker 1: would make three moonwalks across the Descartes Highlands, cover as
• 5:16
  Speaker 1: much terrain as possible aboard the lunar roving vehicles, and
• 5:19
  Speaker 1: return samples of what the geologists were certain would be
• 5:22
  Speaker 1: ancient volcanic flows. A lunar roving flow experiment would measure
• 5:26
  Speaker 1: the temperature gradient beneath the surface. A third attempt in
• 5:29
  Speaker 1: the Apollo program to gather that data after technical failures
• 5:33
  Speaker 1: on previous missions. A small scientific satellite would be released
• 5:37
  Speaker 1: into lunar orbit to measure the moon's magnetic and gravitational
• 5:41
  Speaker 1: fields for approximately one year. Everything about the mission was calibrated, tested,
• 5:47
  Speaker 1: and rehearsed. Young estimated roughly 350 hours of suited training
• 5:52
  Speaker 1: for the surface work alone. The crew had trained at
• 5:56
  Speaker 1: the Sudbury Basin in Ontario in July 1971, the first
• 6:01
  Speaker 1: time American astronauts had trained in Canada. Studying the shatter
• 6:05
  Speaker 1: cone geology of a 97 kilometer impact structure, nearly 1.8
• 6:10
  Speaker 1: billion years old, they had worked nuclear explosion craters at
• 6:13
  Speaker 1: the Nevada test site. where the cratered landscape most closely
• 6:17
  Speaker 1: resembled the lunar surface. They knew the science. They knew
• 6:21
  Speaker 1: the terrain. They were ready. On the morning of April 21st, 1972,
• 6:28
  Speaker 1: with Young and Duke already sealed inside Orion, and preparing
• 6:32
  Speaker 1: for the power descent, Mattingly ran routine checks on Casper's
• 6:36
  Speaker 1: main engine, the engine that would need to fire to
• 6:40
  Speaker 1: bring all three of them home. He found something that
• 6:42
  Speaker 1: should not have been there. The oscillation Mattingly found was
• 6:46
  Speaker 1: in the backup gimbal system of Casper's main engine. Not
• 6:50
  Speaker 1: a catastrophic failure. Not a reading that made the needle
• 6:53
  Speaker 1: slam to red. Something subtler. A tremor in the secondary
• 6:57
  Speaker 1: loop that controlled the engine's ability to pivot and steer.
• 7:01
  Speaker 1: Under normal circumstances, the backup system never fires at all.
• 7:05
  Speaker 1: But if the primary failed during trans-Earth injection, the burn
• 7:10
  Speaker 1: that would push them away from the moon and toward
• 7:12
  Speaker 1: home The backup would be all they had, and if
• 7:15
  Speaker 1: the backup gimbal oscillated under load, the engine could vector
• 7:18
  Speaker 1: off axis. A burn like that does not slow down.
• 7:22
  Speaker 1: It tumbles. Mission control went quiet. Young and Duke were
• 7:26
  Speaker 1: already sealed inside Orion. Suits pressurized, descent checklist running. They
• 7:32
  Speaker 1: had no control over what happened next. They could only wait.
• 7:35
  Speaker 1: Houston began working the problem, pulling engineers, running simulations, calling
• 7:40
  Speaker 1: in specialists to model what the oscillation would do under
• 7:44
  Speaker 1: full engine load. The hours passed. Six hours. The delay
• 7:49
  Speaker 1: was not announced as a crisis, but it was measured
• 7:52
  Speaker 1: in ways that mattered. Every minute that passed was a
• 7:55
  Speaker 1: minute subtracted from somewhere else. The mission timeline was not flexible.
• 8:00
  Speaker 1: It was a chain, each link dependent on the one before.
• 8:03
  Speaker 1: Shorten one link and the chain does not get longer.
• 8:07
  Speaker 1: It just starts breaking at the weakest point. The decision
• 8:10
  Speaker 1: came back from mission control. The malfunction could be worked around.
• 8:14
  Speaker 1: The oscillation fell within manageable limits. Orion was cleared to
• 8:18
  Speaker 1: separate and begin powered descent. Young and Duke undocked from
• 8:22
  Speaker 1: Casper at 23 minutes and 35 seconds past midnight. UTC,
• 8:27
  Speaker 1: April 21st. Six hours behind schedule. They did not know
• 8:32
  Speaker 1: yet which links in the chain were already broken. Orion
• 8:35
  Speaker 1: touched down in the Descartes Highlands at 23 minutes and
• 8:39
  Speaker 1: 35 seconds past 2 in the morning. UTC. Eight hours
• 8:43
  Speaker 1: after the original window. The surface was bright and still
• 8:47
  Speaker 1: and covered in a fine gray regolith that caught the
• 8:50
  Speaker 1: lunar sun at a low angle and threw every pebble
• 8:53
  Speaker 1: into sharp relief. Young stepped out first. Duke followed. They
• 8:57
  Speaker 1: set up the Lunar Roving Flow Experiment. The drill probes,
• 9:01
  Speaker 1: the cables... the sensors designed to measure thermal gradients beneath
• 9:05
  Speaker 1: the surface, and then Young turned to cross to the
• 9:08
  Speaker 1: next equipment station. He did not see the cable. In
• 9:12
  Speaker 1: the Apollo pressure suit, peripheral vision below the waist is
• 9:16
  Speaker 1: nearly zero. The suit is rigid at the joints. Looking
• 9:20
  Speaker 1: down at your own feet requires a deliberate, effortful bend
• 9:24
  Speaker 1: that the suit resists. Young walked through the roving flow
• 9:27
  Speaker 1: cable at a normal stride. He felt nothing. He did
• 9:30
  Speaker 1: not know it had happened. Duke saw it, the cable
• 9:34
  Speaker 1: was severed clean. The sensors were still in the ground.
• 9:37
  Speaker 1: The drill probes were still in place. But the data
• 9:40
  Speaker 1: path from the lunar interior to the recording equipment was gone.
• 9:45
  Speaker 1: Two years of planning. Two previous failed attempts across Apollo
• 9:49
  Speaker 1: 13 and Apollo 15. Three drill holes in the Descartes regolith.
• 9:54
  Speaker 1: And the experiment was over in a single step. This
• 9:58
  Speaker 1: was the chain breaking. NASA managers in Houston assessed the
• 10:02
  Speaker 1: situation and ruled that repairing the cable was not feasible.
• 10:06
  Speaker 1: The time required to splice and reroute the connection, verify
• 10:10
  Speaker 1: the repair, and confirm the sensors were reading correctly. That
• 10:14
  Speaker 1: time no longer existed. The six hours lost to the
• 10:18
  Speaker 1: gimbal delay had already consumed the margin. There was nothing
• 10:21
  Speaker 1: to recover. Young said nothing about the cable that has
• 10:24
  Speaker 1: been recorded as self-recrimination. He moved to the next task.
• 10:29
  Speaker 1: That silence is its own image. They drove. The lunar
• 10:33
  Speaker 1: roving vehicle covered the Descartes terrain. In a way, no
• 10:37
  Speaker 1: astronaut had moved across the moon before. Not on foot carefully,
• 10:42
  Speaker 1: but at speed, wheels throwing small arcs of regolith behind them.
• 10:46
  Speaker 1: as Young steered. The landscape the geologists had studied from orbit,
• 10:50
  Speaker 1: the high albedo region that had looked so persuasively volcanic,
• 10:54
  Speaker 1: unrolled around them in real time. At Plum Crater, Duke
• 10:58
  Speaker 1: climbed down into the rim and lifted out a rock
• 11:01
  Speaker 1: the size of a small suitcase, 111.8 kilograms total mass
• 11:06
  Speaker 1: they would eventually bring back. This one piece, 11.7 kilograms,
• 11:11
  Speaker 1: the largest single lunar sample returned by any Apollo crew,
• 11:16
  Speaker 1: was a breccia, not a lava flow, not a volcanic extrusion.
• 11:20
  Speaker 1: A breccia. Shattered rock fragments compressed together by violent impact.
• 11:25
  Speaker 1: Duke radioed it back to Houston. Impact rock, not volcanic.
• 11:30
  Speaker 1: Houston did not believe him. The scientists in Mission Control
• 11:33
  Speaker 1: had built their entire scientific case for the Descartes site
• 11:38
  Speaker 1: on orbital photographs and Earth-based analogs. The high albedo region
• 11:43
  Speaker 1: looked like volcanic terrain, because there were places on Earth
• 11:46
  Speaker 1: where high albedo regions were volcanic. The geologist who had
• 11:50
  Speaker 1: championed the site had staked a hypothesis on it, and
• 11:53
  Speaker 1: now a 36-year-old Air Force lieutenant colonel standing in lunar
• 11:58
  Speaker 1: dust was telling them the hypothesis was wrong. The response
• 12:03
  Speaker 1: from mission control was not acknowledgement. It was skepticism. Keep sampling.
• 12:08
  Speaker 1: The data would clarify. They kept sampling. Every rock they
• 12:12
  Speaker 1: lifted was a breccia. Every sample told the same story,
• 12:16
  Speaker 1: and up in Casper circling alone through his 64th revolution.
• 12:20
  Speaker 1: Mattingly watched the Descartes formation pass below him, through binoculars,
• 12:24
  Speaker 1: the first command module pilot to use binoculars for lunar
• 12:28
  Speaker 1: orbital observation, and noted that the terrain looked unremarkable, consistent
• 12:33
  Speaker 1: with the surrounding mare-embryum structure. Not exceptional. Not volcanic. Three
• 12:39
  Speaker 1: people were now telling Houston the same thing. Houston kept
• 12:43
  Speaker 1: asking for more samples. The third moonwalk was supposed to
• 12:46
  Speaker 1: last seven hours. The gimbal delay had already taken that
• 12:50
  Speaker 1: time away before Young and Duke ever climbed back into Orion.
• 12:54
  Speaker 1: Mission Control trimmed EV three to five hours. The clock
• 12:59
  Speaker 1: that had started ticking on flight day five was still running,
• 13:02
  Speaker 1: and now it was cutting the last chance to answer
• 13:05
  Speaker 1: the question. Houston still refused to fully accept. Young and
• 13:09
  Speaker 1: Duke drove the lunar roving vehicle northeast toward North Ray Crater.
• 13:14
  Speaker 1: One kilometer wide, 230 meters deep, the largest crater visited
• 13:20
  Speaker 1: by any Apollo expedition. The walls exposed rock layers that
• 13:24
  Speaker 1: no shovel could reach anywhere else on the Descartes surface.
• 13:28
  Speaker 1: Strata laid down by whatever impact had punched that hole
• 13:31
  Speaker 1: into the highlands billions of years before. At the rim,
• 13:35
  Speaker 1: they found house rock. It was taller than a four-story building.
• 13:39
  Speaker 1: A single boulder, its face covered in micrometeoroid impact pits,
• 13:43
  Speaker 1: each one a timey record of collisions across geological time.
• 13:48
  Speaker 1: Not a solidified lava chamber. Not a volcanic intrusion. A
• 13:52
  Speaker 1: mass of shattered and refused material, shaped entirely by impact events,
• 13:58
  Speaker 1: stacked upon impact events. The mission record would later call
• 14:02
  Speaker 1: North Ray Crater and House Rock the final blow to
• 14:05
  Speaker 1: the volcanic hypothesis. The scientists in Houston had spent days
• 14:09
  Speaker 1: asking for more samples, more data, more confirmation. House Rock
• 14:14
  Speaker 1: gave them the confirmation they had been resisting. The Descartes
• 14:18
  Speaker 1: Highlands were not a volcanic highland. They were a landscape
• 14:22
  Speaker 1: built entirely from the violence of ancient impacts. A record
• 14:26
  Speaker 1: of bombardment, not eruption. Every sample Young and Duke carried
• 14:31
  Speaker 1: back to Orion was consistent with the Fra Mauro formation
• 14:34
  Speaker 1: collected by Apollo 14. The two sites, geologically, told the
• 14:40
  Speaker 1: same story. The moon's highlands were not what Earth analogs
• 14:43
  Speaker 1: had suggested. The geologists who had championed the Descartes site
• 14:47
  Speaker 1: had built their model on the logic of a different world.
• 14:50
  Speaker 1: That was the real finding. Not just the rocks, the
• 14:53
  Speaker 1: mission returned to orbit. Mattingly had spent 126 hours alone
• 14:59
  Speaker 1: in Casper. 64 revolutions of the moon. Instrument failures accumulating
• 15:04
  Speaker 1: around him. The panoramic camera had triggered a master alarm
• 15:07
  Speaker 1: on first use. The mass spectrometer boom had jammed and
• 15:11
  Speaker 1: been jettisoned. The mapping camera glare shield had given him trouble.
• 15:15
  Speaker 1: The laser altimeter had degraded and failed before its final
• 15:19
  Speaker 1: scheduled use. He had kept working through each failure, adjusting, logging, continuing.
• 15:26
  Speaker 1: Alone in a spacecraft named after a cartoon ghost, 173,000
• 15:30
  Speaker 1: nautical miles from Earth, He had held the mission together
• 15:36
  Speaker 1: from orbit while two men on the surface rewrote a
• 15:38
  Speaker 1: scientific consensus below him, and then he went outside, 173,000
• 15:45
  Speaker 1: nautical miles from Earth, the second deepest spacewalk in history
• 15:50
  Speaker 1: at that time. Mattingly floated out of Casper's hatch to
• 15:54
  Speaker 1: retrieve the exterior film cassettes, 83 minutes in open space,
• 15:59
  Speaker 1: Duke assisting from the hatch, the Pacific Ocean and the
• 16:02
  Speaker 1: darkness trading places beneath them, As the spacecraft turned slowly,
• 16:07
  Speaker 1: the cassettes came back inside. The film existed. The orbital
• 16:11
  Speaker 1: record survived. They splashed down in the Pacific Ocean on
• 16:15
  Speaker 1: April 27th, 1972. 265 hours, 51 minutes, and 5 seconds
• 16:24
  Speaker 1: after liftoff. The USS Ticonderoga recovered all three crew members
• 16:28
  Speaker 1: 37 minutes after splashdown. Young, Mattingly, Duke... Alive, 95.8 kilograms
• 16:38
  Speaker 1: of lunar samples came back with them. The inventory of
• 16:41
  Speaker 1: what the mission cost is precise and permanent. The Lunar
• 16:44
  Speaker 1: Roving Flow Experiment, the third attempt in the Apollo program
• 16:48
  Speaker 1: to measure the moon's interior temperature, was destroyed when Young's
• 16:52
  Speaker 1: boot severed the cable he could not see. NASA managers
• 16:56
  Speaker 1: ruled a repair attempt too time-consuming, given the compressed timeline.
• 17:01
  Speaker 1: The gimbal delay had taken that window away. six days
• 17:04
  Speaker 1: earlier on flight day five, when the oscillation appeared and
• 17:08
  Speaker 1: several hours of analysis paused the entire mission. The clock
• 17:12
  Speaker 1: that started then never stopped collecting its debt. The small
• 17:16
  Speaker 1: satellite ejected into a lower than intended orbit because the
• 17:20
  Speaker 1: delay had compressed the deployment window, completed 424 orbits and
• 17:23
  Speaker 1: crashed into the moon on May 29th, 1972, 35 days
• 17:25
  Speaker 1: after release. It had been expected to orbit for approximately
• 17:34
  Speaker 1: one year. The mass spectrometer boom never retracted. Jettisoned, and
• 17:39
  Speaker 1: somewhere in the Descartes Highlands, in the dust at the
• 17:41
  Speaker 1: feet of where Orion once stood. A laminated family photograph
• 17:45
  Speaker 1: lies face up toward the black sky. Charles Duke placed
• 17:49
  Speaker 1: it there during the mission. A portrait of his family,
• 17:52
  Speaker 1: signed on the back. His wife, Dorothy. His sons, Charles
• 17:56
  Speaker 1: the Third. and Thomas, a plastic rectangle sitting in vacuum
• 18:00
  Speaker 1: in cold and stillness since April 1972. No mission has
• 18:05
  Speaker 1: returned to the Descartes Highlands. The photograph is still there.
• 18:09
  Speaker 1: What came back in those 95.8 kilograms changed the discipline permanently.
• 18:14
  Speaker 1: The Cayley Formation was confirmed as non-volcanic. Impact breccius throughout.
• 18:20
  Speaker 1: The finding forced geologists to confront the limits of reasoning
• 18:24
  Speaker 1: from Earth analogs to a body, with a fundamentally different
• 18:27
  Speaker 1: geological history. The moon had no plate tectonics, no water erosion,
• 18:32
  Speaker 1: no atmosphere to reshape its surface. What looked volcanic from
• 18:36
  Speaker 1: orbit was the residue of bombardment. The scientists who had
• 18:40
  Speaker 1: initially refused to believe Young and Duke's real-time reports eventually
• 18:44
  Speaker 1: accepted what the samples proved. The model had been wrong
• 18:47
  Speaker 1: because the model had been built on the wrong world.
• 18:50
  Speaker 1: The mission also found something no one had been looking for.
• 18:54
  Speaker 1: The far ultraviolet camera and spectrograph, the first astronomical instrument
• 18:59
  Speaker 1: ever operated from the lunar surface, identified two previously unknown
• 19:04
  Speaker 1: auroral belts around Earth. The crew had traveled 384,000 kilometers
• 19:10
  Speaker 1: to study the moon and returned with a discovery about
• 19:13
  Speaker 1: their own planet. That is the shape of the mission's
• 19:16
  Speaker 1: scientific legacy, a wrong hypothesis, rigorously tested, producing answers more
• 19:22
  Speaker 1: valuable than the ones it sought. The command module Casper
• 19:25
  Speaker 1: is on display today at the U.S. Space and Rocket
• 19:27
  Speaker 1: Center in Huntsville, Alabama. Visitors can walk around it. It
• 19:32
  Speaker 1: looks smaller than it should. Mattingly, who had watched Apollo
• 19:35
  Speaker 1: 13 spiral toward disaster from a console on the ground
• 19:39
  Speaker 1: after being removed from its crew three days before launch.
• 19:43
  Speaker 1: Removed because of a rubella exposure traced to Duke's child,
• 19:48
  Speaker 1: a virus he never contracted. Flew to the moon with
• 19:51
  Speaker 1: Duke two years later. He came home. Duke came home.
• 19:55
  Speaker 1: Young came home. The photograph did not. It remains in
• 19:59
  Speaker 1: the Descartes Highlands, in a place no human being has
• 20:03
  Speaker 1: visited in more than 50 years, facing a sky that
• 20:06
  Speaker 1: has no dawn, waiting in a silence that has no end.
• 20:10
  Speaker 1: The family smiles in it. The dust holds it still.
• 20:13
  Speaker 1: And the question Young and Duke answered up there, about
• 20:17
  Speaker 1: what the moon is made of, about how wrong a
• 20:19
  Speaker 1: confident theory can be when it is built on the
• 20:22
  Speaker 1: wrong assumptions. That question stays open every time a scientist
• 20:26
  Speaker 1: looks at a photograph of a place they have never
• 20:28
  Speaker 1: stood and decides they already know what it means. The
• 20:33
  Speaker 1: clock ran out in April 1972. What it left behind
• 20:37
  Speaker 1: is still ticking. This shows is made by Oboe Media.