Transcript

8.28.25 · Science Show KY

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Speaker 1: Welcome to Radio Wized Diary of Science and Nature, your readers.
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Kelly Taylor. I'll have some articles on the topics of
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science and nature, but first a reminder that RADIOI is
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a reading service intended for people who are blind or
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have other disabilities that make it difficult to reprinted material.
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From Scientific American we have this article dated August twenty second.
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Can SpaceX solve its exploding starships problem? Kaboom is not
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the sound you want a rocket ship to make as
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a rule, yet that's the problem facing the private aerospace
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company's SpaceX and its leader Elon Musk. Instead of going
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to space, their newest rocket ship keeps going kaboom. The
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last three flights of Starship, a two stage, four hundred
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foot tall vehema, ended in fiery disaster what Musk has
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sometimes jokingly called a quote rapid unplanned disassembly. In January
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and again in March, the launch vehicle's super heavy booster
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made it back to a massive pincer equipped gantry, but
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Starship's upper stage didn't. In May, the booster exploded just
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before splashdown, and Starship broke up spectacularly in the atmosphere,
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raining debris that commercial aircraft had to dodge as a bonus.
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In June, the upper stage detonated on the launch pad
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while Starship was getting fuel for a test firing of
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its engines. The tally for twenty twenty five thus far
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is explosions four SpaceX zero. Today, Starships super Heavy booster
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and upper stage or on the launch pad yet again.
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The tenth test flight is scheduled for liftoff on Sunday
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around seven thirty pm from SpaceX's Starbase launch site in
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South Texas. If all goes to plan, the booster will
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use its thirty three rocket engines to push the whole
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chipang to the edge of space, then drop off somersault,
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execute a boost back burn, and descend to a soft
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splashdown into Gulf of Mexico. Meanwhile, Starship's upper states should
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be firing its rockets to reach orbit, where it will
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deploy some cargo before flying itself back down through the
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atmosphere to its own splash down about an hour and
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fifteen minutes after launch. Excitement guaranteed in quotes a SpaceX
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announcement promises, but there's excitement, and there's excitement. Look, going
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to space is hard. It's even harder to do in
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the way SpaceX is attempting. Quote, it's one of the
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biggest rockets ever. It's for sure the biggest rocket that
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has attempted reuse, says Jonathan McDowell, an astrophysicist at the
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Center for Astrophysics at the Harvard and Smithsonian who tracks
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space launches in his spare time. Quote, Developing a vehicle
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this big and launching it repeatedly ain't easy. In quote,
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Starship isn't just an oligarch's polly. It's a launch system
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meant to revolutionize space light by flying cargo and cruise
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to orbit at a cost that's almost too cheap to meter.
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It's supposed to stake to take NASA astronauts back to
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the Moon and human setlers to Mars, and it represents
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the kind of gleaming hardware forward future that Silicon Valley's
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techno optimists are always promising. Starship is the lynchpin of
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a lot of plans and schemes over the past few months.
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SpaceX has acknowledged which pieces of the ship broke with
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each flight, but hasn't gone into any great detail about why.
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The company didn't return requests for comment from Scientific American,
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but SpaceX is very online rocket spotting fans, and the
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half dozen aerospace engineers I talked to have been willing
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to speculate what the problems might be. Mostly they believe
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the company has some brilliant people who stand every chance
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of solving them. But they also wonder what will happen
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if SpaceX can't figure out what's wrong, or even worse,
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if some fundamental engineering issue means the idea of a reusable,
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reliable workhorse Spaceship stays confined to science fiction those SpaceX
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characterizes this differently. Starship had essentially the same types of
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mishap in all three of the most recent flights, leaks, fires,
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and explosions in the fuel system. On flight seven, there
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is a flash and then a fire in the unpressurized
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attic that's in quotes below the bottom of Starship's liquid
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oxygen tech. On flight eight, that happened near one of
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the rocket engines. On flight nine, fuel leaked into the
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rose cone. That fuel and the plumbing to move it
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around might be the problem. It's a mix of liquid
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methane and liquid oxygen of volatile cryogenic cocktail that's still
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by rocket science standards experimental to stay liquid methane has
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to be below negative two hundred and fifty nine degrees
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fahrenheit negative one hundred and sixty two degrees celsius, and
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oxygen has to be even cover below negative to ninety
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seven degrees faharadyt. That means a lot of mechanical effort
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to keep it cold, to move it around on the
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ground and on the vehicle, and to accommodate it as
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it shifts from liquid to gas and gets lit on fire.
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Going back and forth from super cold to hot is
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called thermal cycling. Without careful design and maintenance, almost anything
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under those conditions will break in a Muskian science fiction future,
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that's all worth it. Cryogenic fuel is a pain and asteroid,
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but it has more umph propound as gojus what engineers
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call specific impulse, and fuels like methane offer the tantalizing
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possibility that they could be harvested in c TU on
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another world, that they could be synthesized from carbon dioxide
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and frozen water in Martian regulate, or say, slurped up
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from the roiling methane seas of Titan. And that makes
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living off the land in space seem feasible, even though
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nobody really knows how to do it yet. Quote. Methane
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is a new rocket propellant for space launch, so we're
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still learning how to do the methane plumbing. The fact
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that they've had leaks, the fact that they've had overheating,
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doesn't really surprise me. McDowell says. It's a different sized molecule,
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bigger than liquid hydrogen but smaller than kerosene, so it
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leaks differently in different circumstances. It's chemistry is different, but
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the croogenic chemistry here may be less elevant than cold mathematics.
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Anything going to space has to carry its own fuel,
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but that fuel itself has mass. Quote. That's the tyranny
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of the rocket equation, says Hassan sod Ifty, aerospace engineer
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at Texas A and M University, referring to the calculation
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that vexes every would be space jockey. Quote. You need
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to carry more to deliver what you want, but more
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fuel means more fuel for the fuel end quote. That's
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why rockets often have stages or external boosters. When they
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run out of fuel, you'd drop those components so that
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the rockets will have less mass to lift. Musk's ambitious
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goal is for Starship to carry between one hundred and
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ten and one hundred and sixty five tons of payload
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to orbit, five times what a NASA Space shuttle can
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handle by way of comparison. But to make that work,
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the vehicle itself, the dry mass, without propellant, rocket engines,
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and all the plumbing has to be extraordinarily light. SpaceX
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is aiming for a structural ratio the dry mass divided
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by the sum of the dry mass and the propellant
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of zero point zero five for both stages. Quote. Most
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typical rocket designs, that ratio is around point one, says
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John Deck, an aerospace engineer at Georgia Institute of Technology.
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In other words, Starship is on a pretty extreme weight
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loss regime. Some observers and engineers speculate the diet might
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be the problem. After the failure on flight seven, SpaceX's
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official blog reported that the cause of the leaks and
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fire was a quote harmonic response several times stronger than
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had been seen during testing, which led to increased stress
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on hardware in the propulsion system end quote. That is,
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some Starship's hardware shook itself apart. Deck was previously at
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NASA and his specialty there was entry descent bringing space
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probes down to the surface of Mars. It's one of
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aerospace engineering's hardest challenges. For one thing, the atmosphere gets
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thicker as you get closer to a planet's surface, so
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the force of drag on a descending vehicle changes depending
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on both the density of the air and the speed
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of the vehicle. Drag becomes, in the language of engineering,
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a dynamic load. Quote. If dynamic loads are changing fast enough,
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they can cause the vehicle to start to vibrate. Debt says,
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vibrate all that complicated cryogenic plumbing too much, and very
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bad things happen. After flight seven, SpaceX hardened fuel lines
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to the engines and added vents and the nitrogen gas
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purge system to the attic where the leaks happened. To
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deal happened to deal with the possibility of fires. After
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flight eight, SpaceX insisted that the problems that Starship face
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were completely different, but bloggers. When Redditors passed around a
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purported leak from an insider saying that the root issue
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hadn't changed. It was quote harmonic oscillations in quote vibrations again,
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this time busting methane lines running through the liquid oxygen tank. Again.
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When the tank was full of liquid oxygen, it dampened
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the vibrations, but as the tank empty, the shaking got worse.
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Starships two stages have to structurally support nearly eleven eleven
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million pounds of fuel. The upper stage is meant to
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carry as much as three hundred and thirty thousand pounds
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of payload, so the vessel itself has to be as
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light as possible yet still withstand the buffeting forces of
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launch and re entry. So far it has not. Quote
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they've designed their structure light enough to perform when the
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rocketing nights and once to fly. But maybe, and this
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is speculation, when they're loading the fuel that's causing cracking.
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Neck says. Quote. When a structure is cool, it shrinks.
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If it's rigid and can't move, that's going to cause
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a stress and it's going to break in quote. A
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couple of other pieces of evidence fit this theory. One
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reason the booster may have survived flights that the upper
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stage did not is that the booster doesn't go all
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the way to space, and it comes back to the
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ground at only about forty six hundred miles per hour.
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Starship's upper stage goes all the way to orbit and
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reaches seventeen thousand, five hundred miles per hour. That's a
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lot of kinetic energy to get rid of on re entry,
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usually as heat. Quote this is the physical constraint. If
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he says, we can't get away from it. We have
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to manage this entry, this energy. I'm sorry, we have
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to manage this energy being generated through heating in quote.
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An early version of Starship tried to bleed off that
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kinetic energy with a kind of aerodynamic belly flop that
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ended in a catastrophic law of control. Now the vehicle
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uses its control surfaces and rockets to slow its descent
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and relies on heat resistant tiles, which of course add weight.
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One persistent critic of SpaceX, Will Locket, has argued that
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Starship simply must use more propellant than its builders expected
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for its return flights, adding even more weight. Quote this
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puts incredible pressure on SpaceX to save weight anywhere they
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possibly can, Lockett wrote in his newsletter in March. Quote
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SpaceX is having to make the rockets too light, resulting
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in them being fragile, meaning that just the vibrations from
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operation with a fraction of its expected payload would be
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enough to destroy the rocket in kaboom. Maybe this build, test, destroy,
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rebuild cycle is what you'd expect from a cutting edge
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company like SpaceX, which owes much of its astonishing access
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to iterating like a software startup. The version of Super
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Heavy that's set to launch on Sunday has some major
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design changes, increasing the size and strength of the winglets
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called grid fins, but reducing their number from four to three,
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and aiming for a more controlled, higher angle of attack descent.
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Starship's upper stage will also test several new kinds of
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tiles to protect against the ferocious heat of reentry. This
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is what coders call agile. In practice, though this Silicon
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Valley style approach forces SpaceX to play a very expensive
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game of whack a mole. Quote the way I read
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what Elon's trying to do while is it complicated. And
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when you deal with a very complicated device, there's multiple
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modes of failure, says Joseph Powers, an aerospace engineer at
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the University of Notre Dame, an editor in chief of
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the Journal of Propulsion and Power. Quote, with a rocket
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that almost always results in detonation, each failure is supposed
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to be an opportunity to learn to avoid disaster the
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next time. Quote. They're facing challenges, but I don't see
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any showstoppers. McNeal says, I don't want to minimize the
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problems they're having. It's embarrassing for SpaceX, and they do
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have to fix these things, but they are making progress in.
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Speaker 2: Quote and then we'll turn to Earth dot com. And
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this article is from August twenty sixth Driving change. Electric
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vehicles slash emissions across America. Choosing a more.
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Speaker 1: Electrified vehicle lowers your greenhouse gas footprint, no matter which
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country you call home, and no matter which county you
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call home. A new analysis shows battery electric vehicles to
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deliver the lowest lifetime emissions in every part of the
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contiguous United States, with hybrids and plug in hybrids also
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beating their gasoline counterparts. Researchers at the University of Michigan
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mapped cradle to grave emissions for thirty five combinations of
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electric vehicle class and powertrain, then compared results county by county.
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The team also released a free online calculator so drivers
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can see estimates tailored to what they drive, how they drive,
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and where they drive. Study senior author Greg Caitlin is
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a professor at the University of Michigan School for Environments Sustainability. Quote,
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Vehicle electrification is a key strategy for climate action. Transportation
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accounts for twenty eight percent of greenhouse gas emissions, and
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we need to reduce those to limit future climate impacts
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such as flooding, wildfires, and drought events, which are increasing
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in intensity and frequency, said Kaitlin. Our purpose here was
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to evaluate the cradle to greenhouse gas reduction from the
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electric vacation of vehicles compare with the baseline of gasoline
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powered vehicles. The researchers callied emissions for manufacturing, use, and
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end of life, then layered in real world variables. They
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modeled four power trains, conventional internal combustion or ICEV, hybrid HEV,
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plug in hybrid pH EV, and battery electric b EV. Afterwards,
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the team ran three body classes pickup, SUV and sedan,
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using generic twenty twenty five vehicles that reflect what new
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buyers will see on lots. They captured driving style city
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versus highway mix, and for phivs how often owners actually
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run on battery versus gasoline. Geography mattered in two ways.
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Cold snaps, cold snaps redew efficiency for all vehicles and
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trim electric range. In addition, the carbon intensity of electricity
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varies widely across counties, so the same ev charged for
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a cleaner grid emits less per mile than it would
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in a coal heavy region. Even after accounting for those differences,
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battery electric vehicles still came out ahead everywhere. The major
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finding is simple. Deeds produce lower lifetime greenhouse gas emissions
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than any other powertrain in every county of the contiguous
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United States. On average, gasoline pickups were the biggest emeters,
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at four hundred and eighty six grams of carbon dioxide
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equivalent per mile. Moving to a hybrid pickup cut that
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by about twenty three percent. A battery electric pickup cut
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it by roughly seventy five percent. Payload didn't erase the advantage.
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A battery electric vehicle pickup carrying twenty five hundred pounds
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still emitted less than thirty percent of a gasoline pickup
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with an empty van. On the other end of the spectrum,
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compact electric sedans were the cleanest choice, at about eighty
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one grams of CO equivalent per mile, less than one
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fifth the per mile emissions of a gas pickup range
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matters for manufacturing emissions. The lowest emitting configuration in the
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study was a compact Sedan VIEV with a two hundred
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mile range. Bigger batteries ad manufacturing impact, so stretching range
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nudges lifetime totals up, even as evs retained their use
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phase advantage. While federal incentives are in flux, automakers are
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still steering toward electrification. Ford recently touted a new more
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affordable EV platform as a model t moment for the company.
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Kalen noted the policy industry split that said the global
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tree and is clear quote the government is backing off
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incentives like the electric Vehicle tax credit, but the original
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equipment manufacturers are heavily invested and focused on the technology
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and affordability of evs. EDS are becoming the dominant powertrain
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in other parts of the world, and manufacturers recognize that
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is the future for the US. Two nearby drivers can
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have different footprints in the same model. Colder counties impose
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higher energy demand for heating and reduce CV range. Grid
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mix shifts by county and over time, altering the emissions
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tied to every kilowatt hour. Behavior matters too aggressive driving
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burns more fuel. PHEVs shine only when they are plugged
19:47
in often and driven mostly on electricity. The calculator makes
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those nuances into individualized estimates. Electrification delivers the biggest drop,
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choosing as smaller vehicle compounds the game or many commuters.
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Compact EEV does the most to cut emissions per mile. Trades,
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people who need a truck will still make a large
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dint by going hybrid or electric. Quote. The thing is
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really matching your vehicle with your needs. Kale And said, Obviously,
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if you're in the trades, you may need a pickup truck,
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but you can get a battery electric pickup truck. If
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you're just commuting to work by yourself, I'd recommend to
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SEDANVIEV instead. In quote. Now we'll go to BBC Wildlife
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and the article headline is ten deadliest cats in the world,
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Which the lines are the best killers and which attack humans?
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From August twenty sixth from Tiny Mouse Slayers Legendary man Eaters.
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Cats are among nature's most efficient predators, says summer Ryelander,
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a journalist and photographer for UC Wildlife. Here we rank
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ten wild elines through a combination of their hunting success
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rate and likelihood of causing us harm, so deadliest cats
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in the world. Number one leopard. Leopards are skilled hunters
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for a thirty eight percent success rate. They're beautiful. Rosetted
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coats are unmistakable across Africa, Asia and some parts of
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the Middle East, but these big cats are best admired
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from the distance. Solitary and territorial leopards are on the
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Big five list of African wildlife, along with lions, elephants, rhino,
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and cape buffalo, not for their size, but for the
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difficulty and danger they presented to the big game hunters
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of yesteryear. Leopard attacks on humans do happen in Africa,
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but they're far more commonplace in India, where habitat loss
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leads to an increase in human wildlife conflict. While exact
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numbers are difficult to pinpoint, the International Union for Conservation
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of Nature estimates three hundred and fifty to four hundred
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and fifty leopard attacks per year, with ten percent to
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fifteen percent ending in human fatality. Number two the lion.
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The iconic lion needs little introduction. African lions are social cats,
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often living in prides among grassy savannahs, woodlands and sometimes deserts.
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They're not the most successful hunters, with a twenty five
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to thirty percent kill rate, but they're also not afraid
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to steal a kill from fellow carnivores like hyenas and
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wild dogs. Estimates fall between two hundred to two hundred
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and fifty lion attacks on humans annually, but like leopards,
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lions usually only attack humans with cause, such as when
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feeling threatened or desperate due to prey scarcity. There are
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two famous exceptions, though. A pair of male lions that
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came to be known as the Tsavo man eaters killed
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dozens of railway workers in Kenya's Savo region between March
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and December of eighteen ninety eight. Actual figures are unknown,
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with some estimates as high as one hundred and thirty
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five deaths and more recent studies suggesting a figures closer
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to thirty five, but it is clear the two lions
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were targeting humans as prey number three. The tiger tigers
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are the largest of the big cats, and though they
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have a relatively low hunting success rate at five and
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ten percent, their sheer, size and power makes them formidable credators.
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Tigers can take down buffalo, deer, and wild boar, often
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relying on an ambush technique rather than chasing their prey.
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These remarkable cats can be found in several Asian countries,
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though more than seventy percent live in India. Humans are
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well advised to steer clear of close encounters with tigers.
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They're unlikely to attack without provocation, but estimates indicate approximately
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fifty six human deaths per year occur at the claws
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and jaws of a tiger. Number four is the jaguar,
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the third largest cat in the world. Jaguars are perhaps
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best known for their semi aquatic habitats. Jaguars live in
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Central and South America, often in rainforests and lush wetlands
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like Brazil's biodiverse Panthanal. Here, they use their exceptionally strong
24:29
jaws to prey, with the twenty percent to thirty percent
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success rate upon caymans, a small species of alligator and
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capibaras as well as fish, turtles, papers, and deer. Number
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five is the cheetah. As the fastest land animal in
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the world, the sleek cheetah uses its phenomenal speed to
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make a quick work of its prey. Cheetahs have an
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impressive fifty eight percent kill rate pursuing antelope, warthogs, hares,
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and birds, among other species. These lanky cats can exceed
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ninety centimeters in height, with long tails that help them
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balance at high speeds. Most cheetahs are found in sub
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Saharan Africa, with a small population in Iran. While cheetahs
25:18
are certainly capable of harming or killing a human, cheetah
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attacks are rare enough that there are no documented cases
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of a wild cheeta killing a person. Incidents that do
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occur are nearly always with a captive animal. Number six
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the mountain lion, also known as pumas and cougars. It
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lives primarily in forested regions of North and South America.
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These stealthy and deadly cats hunt deer, elk, and small
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mammals such as squirrels and rabbits, utilizing their speed and
25:51
agility to take prey by surprise. Mountain lions have a
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solid kill rate of about twenty percent, and their willingness
25:58
to take livestock occasionally fuels conflict with humans. Fountain lion
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attacks on humans are not common, but they can happen,
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and attack that occurred in California in March of twenty
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twenty four made headlines as the state's first fatal one
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in two decades. Number seven the snow leopard. Among the
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most elusive of wildcats is the snow leopard. They live
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at high altitudes in Central and South Asia, protected from
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the cold by their dense, well camouflaged fur. Despite harsh
26:30
conditions and an estimated kill rate of ten or fifteen percent,
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snow leopards are comparatively excellent hunters. Their strength allows them
26:39
to leap fifteen meters high and take down prey three
26:43
times their size. Due to their remote habitat, snow leopards
26:47
are not considered outwardly deadly to humans. Number eight The servile.
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Servals are fast, capable of speeds around sixty five kilometers
26:57
per hour and their excellent hunters with two percent success rate,
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preying on rodents, frogs, and birds, and even snatching the
27:05
latter out of the air with an impressive two meter
27:08
vertical leaf. Servals are not considered dangerous to humans, though
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provoking one may well prompt an unpleasant attack. Number nine
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black footed cat. Black footed cats live in Southern Africa,
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primarily Botswana, South Africa, Namibia, Namidia, and hunt rodent small birds, insects,
27:28
the occasional hair. Much of their success comes from skill,
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some of it can be attributed to frequency. Black footed
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cats spend about seventy percent of the night hunting and
27:39
perhaps unsurprisingly, these little cats pose no threat to humans
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and finally number ten, the rusty spotted cat. The rusty
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spotted cat is thought to have a similar hunting success
27:51
rate to the black footed cat, using its speed an
27:54
incredible eyesight to overtake prey. It is maybe deadly, but
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it is not a danger to humans. Well that's offer
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today's diary of science and nature. Your reader was Kelly Taylor.
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Now stay tuned for further programming on the RADIOI