SCOTT DETROW, HOST:
Here with another edition of spacing out with our friends from Short Wave, Regina Barber and Berly McCoy. Hey there.
REGINA BARBER, BYLINE: Hey.
BERLY MCCOY, BYLINE: Hey, Scott.
DETROW: So what are we talking about today within space?
BARBER: Yeah, Scott, we're talking about little transforming robots on the moon.
DETROW: OK.
MCCOY: Also, some drama in the astronomy world about how our universe is expanding.
DETROW: OK.
BARBER: And lastly, we have to, of course, talk about the Artemis II and III crews and how they trained for future missions to land on the moon.
DETROW: Well, before we talk about that, I guess I need to know whether there are transformers on the moon because I do feel like I've seen that movie.
BARBER: Yeah. I'm sorry, Scott. We're not talking about Optimus Prime landing on the moon. These are small, like, cute little round robots about the size of a baseball. And they roll out of a lunar lander, and after cracking open, like, down the middle, each half of the sphere moves outward, and it reveals a little camera in the center. And the halves kind of act like spinning wheels, and they kind of waddle and roll over hard terrain. And these little rovers, they're autonomous, too. They basically navigate on their own.
DETROW: This seems so cool. I mean, like, I love the image.
BARBER: Yeah.
DETROW: The autonomy is interesting. I do have to ask why were they there?
MCCOY: Well, mostly for testing. They were part of the first successful Japanese lunar landing a couple years ago. And there's a new study out last week in the journal Science Robotics that analyzed how these little guys performed up on the lunar surface.
DETROW: Other than kind of waddling around and seeming like "WALL-E" characters...
BARBER: Yeah.
DETROW: ...What was their scientific job?
BARBER: So they took a lot of pictures...
DETROW: OK
BARBER: ...Of the moon's surface and of the lander. They're basically scouting out the terrain ahead of bigger rovers and going places they can't.
MCCOY: And, Scott, just to underline this, they're really small. They only weigh about half a pound, and that's huge for space travel, right? The lighter something is, the easier and cheaper it is to put up into space.
BARBER: And I talked to Roger Wiens, a planetary scientist who didn't work on this program, and he was thoroughly impressed. He said that the redundancy was a huge benefit to these devices.
ROGER WIENS: There are not expensive devices. You can have several of them. And if one or two fails, then you still have others.
DETROW: One other thing, though, I'm thinking about the fact that the moon has one-sixth of the Earth's gravity.
BARBER: Yup.
DETROW: So does that affect how they move around?
MCCOY: Totally. Yeah, these little guys actually kind of bounce, though.
DETROW: Oh.
MCCOY: So it's another reason why they're super cool. They're designed for low gravity so they can explore other places like Mars or even asteroids. Here's Roger again.
WIENS: These could go to small asteroids, where hopping is extremely easy. In fact, you got to make sure you don't hop out of orbit or something like that. So yeah, I can see these things going to a number of places. We'll have transformers on various planets and asteroids, eventually.
DETROW: OK, this is a really fun start. We need to shift to something much more existential, though, for all of us...
MCCOY: Yeah, true.
DETROW: ...And that is our ever-expanding universe. First of all, remind us what this debate has focused on over recent decades.
MCCOY: OK, so, Scott, almost 30 years ago, astronomers discovered that our universe is not only expanding, but that expansion is speeding up. But in the last few years, a group of scientists shook up that understanding by claiming that the expansion isn't speeding up, but slowing down. Now, a paper out last week in the journal Monthly Notices of the Royal Astronomical Society pushes back and says the old framework still stands, continuing the debate.
DETROW: So we're back to expanding.
BARBER: Expanding and accelerating.
DETROW: OK. OK. So given that we're back to that point of view, what do the expansion-of-the-universe-is-slowing-down folks say to that?
BARBER: The group of scientists at Yonsei University in South Korea stands by their work. They already posted a rebuttal to this paper, and they say that the standard way astrophysicists measure universe expansion now is fundamentally flawed.
DETROW: So for the nonastrophysicists out there...
BARBER: Yeah.
DETROW: ...Remind us how you measure this.
BARBER: I'm going to let Berly do this.
DETROW: OK.
MCCOY: Yeah, so astronomers basically measure the brightness of a special type of exploding star, a supernova, and then correct for things like how long it explodes or how much dust is in the way.
BARBER: And the South Korean team has said, astronomers, we haven't been including the age of the stars' home galaxy in those corrections, so the math is off. And when you include that, the final answer is that the expansion of the universe is slowing down. Which would be a massive discovery if that were true.
DETROW: This is quite the big if true.
BARBER: Exactly.
DETROW: So OK. So given all of that, though, what is the consensus among other astronomers?
MCCOY: So the experts we spoke to were skeptical of the slowdown hypothesis. They say the community has been fine-tuning the supernova method for almost 30 years, and there are other methods that point to the universe's expansion speeding up.
BARBER: Yeah, we talked to Priyamvada Natarajan, an astrophysicist from Yale University who wasn't involved in this work, and she's still skeptical, but she says these debates are what strengthens science.
PRIYAMVADA NATARAJAN: Scientists by nature are skeptical, and even for an idea that has been validated and accepted - right? - if there is a new argument, we do take it seriously, and we interrogate it.
DETROW: And it's a low-stakes debate, right? 'Cause it's only just like the fate of the universe that's at stake.
MCCOY: Yeah. Instead of everything eventually drifting far apart from each other and dying a cold death billions of years from now, the universe could simply implode, what astronomers call the big crunch. Sadly, none of us are going to be around to see that.
BARBER: I'm team cold death.
DETROW: Don't know which one I prefer.
MCCOY: Hard to choose, huh?
DETROW: Yeah. Nonissue for me, I guess. Something that is happening in our time spans, though...
BARBER: Yeah.
DETROW: Our favorite NASA program, Artemis - we've got to talk about it.
BARBER: Totally. The crew for the next mission, Artemis III, was just selected, and this is the mission that will do lots of maneuvers in space in low Earth orbit. Scott, you spoke with one of the newly selected astronauts, right?
DETROW: I did. The day he was selected, I talked with Andre Douglas, and one of the things he talked about was going on training missions. He was on the backup crew for Artemis II.
BARBER: Yeah.
DETROW: And he trained alongside them.
BARBER: Yeah.
DETROW: And one of the things they did was go to Iceland.
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ANDRE DOUGLAS: We did a, like, 24-mile hike in two days in Iceland just to go through a hard challenge of land navigation as if we're, you know, learning how to be really good operators.
DETROW: And they do this, you know, as you know, because this mission is supposed to help prepare them for a future lunar exploration. So they're looking for places on Earth that are kind of analogs of the moon, of lunar conditions.
BARBER: Yeah. And it's also about geology. Like, the rocky terrain and the actual rock compositions are very similar between the moon and Iceland. Apollo astronauts actually trained in Iceland, too, way back when, and said it was the closest thing they had seen to the moon's surface. Two NASA astronauts are going back there this July to train in Iceland.
DETROW: And this isn't just for lunar missions, right? They're actually - NASA - it's farther away, but they're trying to simulate Mars as well right now?
BARBER: Yeah.
MCCOY: Yeah. So they've had astronaut hopefuls trek around the lava beds in Hawaii Volcanoes National Park with big packs on their backs, doing geological fieldwork and dealing with very limited and very delayed communications from a simulated mission control. It's all a way to make sure our astronauts are super well prepared when someday they are out in space doing the real thing.
BARBER: And Scott, there is a simulated Mars mission happening right now at NASA's Johnson Space Center in Houston. NASA has four researchers in this 3D-printed habitat doing experiments as if they're living on Mars. They went in last October, and they'll stay inside for a little over a year. And maybe, you know, we'll come back and talk about that when they emerge.
DETROW: Sounds great. That is Regina Barber and Berly McCoy of NPR science podcast Short Wave. Thank you for coming into our simulated Earth environment of this NPR radio studio.
BARBER: Thank you.
MCCOY: Anytime. Transcript provided by NPR, Copyright NPR.
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