Short Wave - Planetary Scientists Are Excited About Uranus

Episode Date: April 28, 2022

Probes to Uranus and to one of Jupiter's moons where conditions might support life; a better plan high-quality science on the moon--those are some of the recommendations in a new 700 page report to NASA. NPR science correspondent Nell Greenfieldboyce has looked at that report and talked to the experts. Today, she sifts through all the juicy details of where NASA is headed the next few decades.Read the decadal survey. Probe the Short Wave minds by emailing [e-mail] pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Back in grade school, when we learned about the solar system and made those models of all the planets going around the sun, there was one planet that always got the class snickering. You know what I'm talking about. It's Uranus. Even grown-ups make fun of Uranus. That's NPR science correspondent Nell Greenfield Boys. Hey, Aaron. This is the first time I've been with you on Shortwave. I'm so glad to talk to you. It is totally a pleasure. Thank you for coming and joining us. So now, some people call Uranus Uranus. Both are acceptable, but really, is Uranus any better?

No. I mean, to me, it's a cop-out and a futile attempt at some kind of dignity here. We just have to get used to saying Uranus. We have to embrace it because we are going to be saying Uranus a lot in the coming years. Or at least you are, right, since you're covering. science in NASA. It's my understanding that Uranus will be the target of a major flagship mission for NASA. It's looking that way, yeah, because that planet just topped a kind of special scientific wish list that planetary scientists draw up once every decade to sort of tell NASA what their priorities are. And does NASA usually listen to their recommendations?

Yeah, absolutely. It's highly influential. I mean, the top items on the last wish list, the one put together back in 2011, are in the works right now at NASA. I mean, that's a mission to bring home some rock samples from Mars and another to visit a moon of Jupiter that has an ocean of water beneath an icy surface. I like the sound of that. So today on the show, we're going to talk about the future of planetary science, how planetary scientists drop their wish lists, and where they think NASA should go, in addition, to Uranus. I'm Aaron Scott, and this is Shortwave, the Daily Science Planetcast from NPR. So, Nell, you were saying these wish lists come around once every decade.

So how on Earth do planetary scientists get together and come to some kind of consensus on where NASA should go? They'd obviously like to go everywhere, right? The solar system is huge. There's lots of cool planets and moons. But money is finite. Yeah, and rocket ships are expensive. Compared to human spaceflight?

Actually, I think of them as being kind of cheap. But yeah, in the grand scheme of things, they are expensive. And so what happens is every 10 years, the National Academies of Sciences, Engineering, and Medicine convene an expert committee to do what's called a decadal survey. And so they read hundreds of papers and proposals and they assess the state of the science. And then they issue this big report with recommendations for future missions that are the top priority. Basically, the ones that seem doable and that would answer the most comprehensive. compelling scientific questions. And, you know, this kind of survey of the field is exhaustive. The latest report is over 700 pages long. And for the world of planetary science, this is a huge,

huge deal because it sets the stage for where NASA will be focused in the years and decades to come. So this time the big winner was Uranus. Yep, that's the headline. I got to admit, now, I don't actually know a lot about Uranus beyond what I learned in middle school. It's the seventh planet from our sun. It's a lovely shade of blue. It's got rings and a strange tilt and numerous moons. It's very far away and very, very cold. So why does scientists want to go there?

Well, because they don't know much about it either. So our solar system basically has three types of planets. You've got your rocky planets like Earth and Mars. And then your gas giants, that's like Jupiter and Saturn. And then there are the ice giants. So that's Neptune and Uranus. Ice giants are smaller than the gas giants, and they have a lot of icy materials around a rocky core. And NASA has never sent a dedicated mission to orbit and study an ice giant.

We're sure there are going to be lots of surprises once we get there. Robin Knup is a researcher at Southwest Research Institute. She co-chaired the Decadal Survey Steering Committee. And she told me that when scientists detect planets around other stars, so, you know, like other solar systems far away. they see a lot of planets that appear to be ice giants. They're likely the most common class of planets in the universe. But we don't know that much about them. And that's why the committee was like,

let's go see one of the two that's in our own backyard. Yeah, what's the closest we've actually ever gotten to Uranus? The only spacecraft to even come close was NASA's Voyager 2 mission. That was in 1986, but it was still pretty far away. It was like within, you know, about 50,000. miles. So this mission that the scientists want to see would both orbit Uranus and send down a probe. The jokes write themselves. Indeed. And, you know, as you said, we're going to be in for decades and years of this, because if NASA goes along with this recommendation, a spacecraft would

launch like in the early 2030s. That's a ways off. I'm assuming there are other destinations in the report too, right? Yeah, there's a bunch. I mean, the other big recommendation was to send a mission to a moon of Saturn called Enceladus. And, you know, Phil Christensen is another co-chair of the steering committee. And he told me if what you really want out of solar system exploration is to find extraterrestrial life. Enceladus is the logical candidate to go to try to look for evidence of life today. Oh, yeah. I was just talking about this with an astrobiologist a couple weeks ago.

It's one of the icy moons where we think there could be water underneath and possibly geothermal vents, right? Yeah, so this moon is pretty small. It's only about 310 miles across, but it appears to be incredibly active for such a small place. It has this icy crust and there seems to be liquid water underneath it. And then, you know, giant geysers. There's giant geysers that shoot water vapor from that ocean out into space. And the Cassini mission to Saturn found that there seems to be simple organic materials there. And, you know, this rocky core beneath the ocean. is probably putting out heat. And you get all these ingredients you need for life in this little place. I mean, you can imagine a lander could just sit there on the surface and let material that shoots out in the jets kind of rain down on it. So, you know, you could analyze material that originated deep within and look for evidence of life.

That's pretty cool. So when would we see a mission like that? Ah, that one wouldn't happen until like 2050. Speaking of, you mentioned that NASA is still working on missions that were the top priority the last time around, the last time these planetary scientists got together and did this big once a decade review. Yeah. And one of those is a mission to get pristine rocks off the surface of Mars.

And that's called Mars sample return. It's been a priority for planetary scientists for literally decades. I was talking about this with Casey Dreyer. He's a space policy expert with the planetary society. Mars sample return first appeared as the gleam in the eye of an acid budget. in 1978. Right. So this is a culmination

of 50 years of effort. We do have some Mars rocks here on Earth already because every once in a while a meteorite that falls out of the sky is a rock that actually came from Mars. But a Martian meteorite,

by definition, you know, got cooked and it traveled through space and altered and all that kind of stuff. So what scientists want is like an unaltered rock like they were there and picked it up with their own hands.

Exactly. One that they could bring to a lab. and run all kinds of tests looking for any evidence of life, you know, past life, present life, even. Yeah, now, this sounds like the plot to some sci-fi film where some Martian germ wipes out all life on Earth. Believe me, that kind of thing is a big part of this mission's planning. I mean, you want zero contamination of Earth and zero contamination of the Mars samples. Right now, there's this rover on Mars, Perseverance, which got there last year, and it's been drilling rock samples and then sealing them up in tubes.

And NASA is working on a plan to retrieve those in collaboration with the European Space Agency. The hope is that this effort would launch in 2028 and bring samples home in the early 2030s. This sounds super cool and finally something that's not that far away. Yeah, and planetary scientists really hope it will stick to that schedule because any delays might mean cost overruns. And this mission is already super expensive.

Casey Dreyer spends a lot of time analyzing NASA's budget, and he told me, right now, funding for planetary science is at record high levels. But the whole field is eyeing the rising costs of Mars sample return. And he says costs are also rising for another big mission in the works, a probe called the Europa Clipper. It's going to be sent to a moon of Jupiter that, again, has a liquid water ocean under an icy crust. You know, this is yet another intriguing place to look for life. It was another big priority in planetary scientist's last wish list from 10 years ago. And so, you know, it's an interesting situation to be in where we have record levels of funding, but I think at the same time, we are being squeezed by two major missions,

which is Marsempa return in Europa Clipper. The concern is basically, you know, if these big flagship missions have ballooning costs and the budget for planetary science remains constant, the result. the result might be delaying or taking money away from, you know, smaller missions. And there are smaller missions, right? I mean, we've been talking about Uranus and the Mars sample return, which are these really big, expensive missions. But that's not all that's on the books. Absolutely.

NASA is pursuing a slew of other things. There's a couple of missions in the works going to Venus, our next door neighbor. And this report laid out a bunch of other worthy destinations for lower cost trips, like to the dwarf planet series and to Titan, that's Saturn's largest moon. Yeah, speaking about moons, now, what about our moon? I mean, NASA's currently trying to go back there too, right? Yeah, so NASA has vowed to put the first woman and person of color on the moon. They're working on this.

They've spent billions building a rocket and a space capsule, and the goal is to land in 2025, but they're pretty surely will be delays. you know, the planetary scientists who wrote this report actually expressed a lot of concerns about the lack of science that's being planned for this human exploration effort. Huh. What do you mean? Well, at NASA, ever since the end of the Apollo program, it's been robots doing exploring, you know, not so much people. Human spaceflight has been close to Earth, like building and visiting the orbiting International Space Station.

Right. And this report that just came out said, look, you know, there's this disconnect within NASA between science and human exploration that needs to be fixed if we're going to get any great science out of the return of people to the moon. So these folks were telling NASA, look, you know, you can gather priceless geologic samples and do amazing planetary science at the moon, but you really need to get your act together on this one.

Well, at least they have a few years to figure it out. Now, thanks for stopping by to talk planetary science with us. We'll have you back when these various missions come to fruition. Right now 2050 is looking pretty open. And we can say uranus ad nauseum. Indeed. This episode was produced by Rebecca Ramirez, edited by Giselle Grayson, who is also our missions, ground control, Margaret Serino checked the facts, Patrick Murray was the audio engineer,

Neil Carruth is our senior director of On-demand news programming, and Anya Grunman is our senior vice president of programming. I'm Aaron Scott. Thank you for listening to Shortwave, the Daily Science Podcast from NPR.