SpaceX’s Starship Completes In-Orbit Engine Test

KATHLEEN DAVIS: This is Science Friday. I’m SciFri producer Kathleen Davis. Later in the show, it’s been 50 years since scientists discovered one of our oldest relatives, the famous hominin Lucy. Plus, Asheville, North Carolina just restored clean drinking water 53 days after Hurricane Helene. We’ll take a look at the science of water purification and why it can take so long after a major storm.

But first, on Tuesday, rocket company SpaceX conducted another test flight of its Starship spacecraft. The rocket did launch successfully, but the company decided not to try some landing acrobatics.

Joining me to talk about that and other stories from this week in science is SciFri’s own Charles Bergquist. Hey, Charles.

CHARLES BERGQUIST: Hey, Kathleen.

KATHLEEN DAVIS: So tell me more about this launch.

CHARLES BERGQUIST: Yeah. So this was the sixth test flight of SpaceX’s Starship craft. This was uncrewed, so no people aboard. And it lasted about an hour. And the big question that they were looking at here was whether or not they could restart the engines while in orbit, which obviously is something you’d need to be able do to make big course and orbit changes. And it turned out that engine restart worked.

KATHLEEN DAVIS: So they didn’t hit all of their goals for launch, though, right?

CHARLES BERGQUIST: Yeah. So this was a stretch goal, you might say. You might have seen back in October this maneuver where the booster stage, the Super Heavy booster, returned to the launch tower and was caught upright, almost like a pair of giant chopsticks clamping onto the sides of it. A repeat of that move was on the table for this launch. But at the last minute they made a choice not to do that, and instead let the booster splash down into the ocean.

KATHLEEN DAVIS: OK, I see. So it’s my understanding you have a related story about Starship. Tell me about that.

CHARLES BERGQUIST: Yeah. So this Starship Super Heavy booster combination is big, really big. And launching that takes a lot of rocket power. This thing has 33 engines.

KATHLEEN DAVIS: Wow.

CHARLES BERGQUIST: If you’ve ever been near even a normal rocket launch, you know that they’re loud. So researchers asked, just how loud is a Starship launch. And it turns out a team from BYU placed a bunch of sensors around the area to monitor some previous launch attempts.

KATHLEEN DAVIS: OK. So what did they find?

CHARLES BERGQUIST: Well, big secret here– it’s really, really loud. Not so much a sound, it’s like a force. Even 10 kilometers away, we’re talking rock concert levels of sound here. And at 20 kilometers, think table saw, snow blower, something like that. And 30 to 35 kilometers away, you’re still looking at sound levels like a vacuum cleaner or a hair dryer.

KATHLEEN DAVIS: Wow. This might be a silly question, but aren’t all rockets really loud?

CHARLES BERGQUIST: Yeah. Sure, it’s a rocket. Of course, it’s loud. But this is really louder than many other launches. SpaceX has a smaller launch vehicle that they use a lot called Falcon. This Starship Super Heavy combination launch was the equivalent of 10 Falcon rocket launches.

KATHLEEN DAVIS: Wow.

CHARLES BERGQUIST: And the estimates are that the noise is equivalent to around five launches of the Space Launch System. That’s the launch vehicle under development for part of NASA’s Artemis program.

KATHLEEN DAVIS: Does that level of noise affect anything?

CHARLES BERGQUIST: Yeah. It could, right. This is the kind of sound pressure that can actually start to cause cracks in walls or windows. After the October test launch, there were some reports of property damage in the town nearby the launch site. Those haven’t been really officially tabulated. But there’s also the question of whether this might be harmful to wildlife nearby, especially as the frequency of these launches ramps up and they use it more.

KATHLEEN DAVIS: So something to keep an eye on as this goes forward. Let’s stay in space for our next story. There’s something more distant in the news.

CHARLES BERGQUIST: Yeah, this is a story coming out of the European Southern Observatory’s Very Large Telescope Interferometer project. They were able to take a zoomed in, close up image of a star called WOH G64. What’s significant here is this is a star 160,000 light years away.

KATHLEEN DAVIS: Wow.

CHARLES BERGQUIST: Yeah. It’s not even in our own Milky Way galaxy. It’s in another galaxy called the Large Magellanic Cloud.

KATHLEEN DAVIS: OK. So we were able to get this close up image. What did it look like?

CHARLES BERGQUIST: Yeah. You see this glowing, egg shaped ring surrounding a fuzzy thing. And astronomers think that what they’re seeing is gas being driven off from the star. It’s shedding all this gas rapidly as it moves through the last stages of its life. And some of the astronomers think that this star is dying and could someday become a supernova.

KATHLEEN DAVIS: OK. So how were they able to even get this image?

CHARLES BERGQUIST: Yeah. One factor here is just advances in telescope technology. This instrument is actually for big telescopes in Chile that can combine together into one interferometer instrument to see extra small things. But it’s not really cheating, but this star is a red supergiant and is something like 2,000 times the size of our sun. So you’re not seeing our sun in a distant galaxy, but this is still a super impressive result.

KATHLEEN DAVIS: So yeah, this is a very large object, to put it mildly.

CHARLES BERGQUIST: Yes, very large.

KATHLEEN DAVIS: OK. So back here on Earth for our next story, there are advances in dealing with the chemicals known as PFAS chemicals or forever chemicals. Tell me about those, Charles.

CHARLES BERGQUIST: Right. So these are a group of chemicals called perfluoro and polyfluoroalkyl substances. Basically, that means that they have a lot of carbon fluorine bonds in them. And those bonds are really strong, chemically. On the one hand, that’s part of what makes these chemicals useful for a lot of things like flame retardant, stain repellents, non-stick coatings. But it also means that they’re very hard to break down.

And that’s what these two papers in Nature this week are discovering. The researchers found that by using catalysts that were activated by light, they were able to break that tough bond at pretty mild temperatures. Normally, these bonds take a lot of energy to break, and that’s usually in the form of heat. You’ve got to really crank up the heat to get this bond to break. But the light-activated catalysts were able to get over that energy hurdle a lot easier.

KATHLEEN DAVIS: So obviously, PFAS chemicals are a big problem. They’re on a lot of people’s minds. Is this a possible solution?

CHARLES BERGQUIST: So this is a start. Neither of these catalyst systems is really ready for prime time yet. Importantly, one of the big troubles, as you know, with the PFAS chemicals right now is when they get into people’s water supply. But these particular catalysts don’t work all that well in water. So there are some challenges to be worked out here to make this really useful.

KATHLEEN DAVIS: All right. So maybe a piece of the puzzle, but we still need a lot more solutions. So turning from light to sound, there is a study this week about how whales hear. Tell me about this, Charles.

CHARLES BERGQUIST: Yeah. So this is published this week in Science. And I don’t know about you, but I usually think of whale noises as mainly being low frequency sounds with those incredible songs that they do. Right. But in this research, the scientists were actually able to give two minke whales a hearing test, and they found that they can hear at higher frequencies than they previously thought.

KATHLEEN DAVIS: Charles, I’ve got to ask, how do you give a whale a hearing test?

CHARLES BERGQUIST: So I don’t know if you ever had to do this in elementary school. You strap the big clunky headphones on the head and you raise the flipper when you hear the beep on each side. No, this is not what they did.

First, they had to safely catch the whales. They found a natural channel that ran in between two islands in Norway. that migrating whales tended to swim through. And in this area, they set up a system of net barriers to temporarily restrain two adolescent minke whales. Then they put electrodes on the surface of their skin in the place of those big, clunky headphones. So this is a non-invasive procedure. And they played sounds of the whales and watched the electrical activity.

And they found that the minkes could detect frequencies as high as 45 to 90 kilohertz, which is much higher than they previously thought, just looking at the ear structures and listening to the sounds that they usually make when they’re singing.

KATHLEEN DAVIS: All right. Well, I understand you have some other animal news, this time of the feline variety.

CHARLES BERGQUIST: Yeah. So this one is terrestrial and a lot older, and also super cute. Researchers uncovered a 35,000-year-old saber-toothed kitten in the Siberian permafrost. They think that the kitten was probably around three weeks old when it died. But what’s really cool here is how well it was preserved. You can see claws and whiskers and really thick, soft-looking dark brown fur all over it. This was research published in the Journal of Scientific Reports.

KATHLEEN DAVIS: And I highly recommend that everybody look up pictures of this kitten because it is extremely cute. But I suspect it’s best not to play with a saber-toothed kitten. Am I right, Charles?

CHARLES BERGQUIST: I’m guessing that would probably not be wise.

KATHLEEN DAVIS: All right. Well, on the topic of play, there is news about the Pokémon GO game, which I hadn’t heard about in quite some time. What is this news?

CHARLES BERGQUIST: Yeah. So this is a game that was launched in 2016. That’s of a type known as augmented reality. It uses GPS signals combined with images from your mobile phone’s camera to put game images like Pokémon creatures or other things into real-world scenes around you. So if, for example, went to a place that the game decided contained one of these Pokémon, and you looked through your phone’s camera, you’d see the Pokémon hiding next to a real tree in your neighborhood, for example.

The news this week is that Niantic, the developers of the game, also were using all those millions of pictures that people were taking to train an AI, and they actually used it to develop navigation software.

KATHLEEN DAVIS: Is there anything that isn’t being used to train AI these days?

CHARLES BERGQUIST: Yeah, it’s really a pressing issue. You think about artists and authors who are upset about their work being slurped into these AI models without their permission. But here, this is pictures taken by people who thought they were just playing a game.

KATHLEEN DAVIS: Yeah. Well, this is something we’ll definitely be seeing more of, I suspect. But we have time for one more story. And this is also on the topic of games. But we’re talking about chimps, right?

CHARLES BERGQUIST: Right. So play is a thing that the young of many animal species do. It’s a way for kids, children, young, to learn about the world around them and try out things safely. But sadly, most animals stop being quite so playful as they age, and humans are an exception to that. Adult humans still play, whether you’re in a softball league or you have a weekly poker night.

But now, researchers are reporting in the Journal of Current Biology that it turns out adult chimps also play even when they’re older. They found that some chimps, like people, continue to play throughout their entire lives. And they think this is especially important before engaging in some kind of act that requires collective cooperation. So play helps you work together.

KATHLEEN DAVIS: Well, that is just some lovely news to send us off into the weekend. Thank you so much, Charles.

CHARLES BERGQUIST: You bet, Kathleen. Thanks for having me.

KATHLEEN DAVIS: SciFri Senior Producer Charles Bergquist.

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