A Trip To An Asteroid…And Back

10:10 minutes

a computer rendering of a satellite next to an asteroid
The Hayabusa2 spacecraft. Credit: NASA

Last week, the Japan Aerospace Exploration Agency, also known as JAXA, landed two rovers on the asteroid Ryugu. The Hayabusa2 mission will explore the surface of the asteroid, blast an impactor into it to study the core, and return to Earth with samples.

Thirteen years earlier, JAXA unsuccessfully tried to land a rover on a different asteroid. For this most recent mission, Hitoshi Kuninaka, Director of Director of the Space Exploration Innovation Hub Center for JAXA and former engineer on the Hayabusa missions, said they “changed the operational philosophy from manual to automation. The release of the robotics fully controlled by onboard computer instead of manual operation from the ground.”

[How can you help one of earth’s most endangered ecosystems? Try out this activity.]

Bruce Betts, Chief Scientist of the Planetary Society, discuss how JAXA engineered these ‘hopping’ rovers and what this will add to our understanding of space science.

Plus, video producer Luke Groskin talks about his visit to a lab where scientists are mixing up recipes for asteroids here on Earth to help researchers test rovers for future missions.

Segment Guests

Hitoshi Kuninaka

Hitoshi Kuninaka is Director of the Space Exploration Innovation Hub Center (TansaX) in the Japan Aerospace Exploration Agency (JAXA), based in Tokyo, Japan.

Bruce Betts

Bruce Betts is Chief Scientist of the Planetary Society, based in Pasadena, California and author of Astronomy for Kids: How to Explore Outer Space with Binoculars, a Telescope, or Just Your Eyes.

Luke Groskin

Luke Groskin is Science Friday’s video producer. He’s on a mission to make you love spiders and other odd creatures.

Segment Transcript

IRA FLATOW: Last week, the Japan Aerospace Exploration Agency, or JAXA landed two rovers called Minerva 1A and 1B onto the asteroid Ryugu, the first successful landing on an asteroid ever. Hayabusa2, the spacecraft that carried these rovers, crossed millions of miles during its three-year trip. But for the JAXA scientists, the journey was much longer than that. Over a decade ago, the original Hayabusa missed its target asteroid, Hitoshi Kuninaka who is now the director of the space exploration innovation hub center of JAXA, was an engineer who worked on the ion propulsion systems for both missions. We spoke to him, and he said the problem with the initial mission may have been that it was manually controlled by engineers here on Earth.

HITOSHI KUNINAKA: And then so for the Hayabusa2 mission, we changed the operational philosophy from the manual to automation. These are the robotics actually controlled by another computer, instead of the manual operation from the ground. After the long effort and a lot of the experience, we are very, very happy.

IRA FLATOW: Indeed, they are. The JAXA scientists were successful by learning from previous mistakes. But Kuninaka says to complete understand asteroids– completely understand asteroids– it’s going to take a bigger effort.

HITOSHI KUNINAKA: NASA is also executing a [INAUDIBLE] mission to go to the asteroid belt. So JAXA’s approach and the NASA’s approach and the European approach, we will make new legion of the space science is to study asteroid science, cooperating each other.

IRA FLATOW: Hitoshi Kuninaka now director of the space exploration innovation hub center of JAXA who is an engineer on Hayabusa missions. Here to tell us more about Hayabusa2 and what this means for asteroid scientist Bruce Be He’s the chief scientist at the Planetary Society in Pasadena. He’s worked on creating instruments for space missions and author of Astronomy for Kids. Welcome, to Science Friday.

BRUCE BETTS: Thanks, good to be here.

IRA FLATOW: And nice to have you. We heard from Dr. Kununaka and mentioning the change in philosophy between Hayabusa2 and the previous mission. What other changes did they make?

BRUCE BETTS: They improved some of the things that they had issues with on Hayabusa. So their propulsion was more powerful and more reliable. Their antennas were modified. Their attitude control system and navigation systems had upgrades, and then they added in a bunch more things to drop off the spacecraft and do cool stuff from little hoppers to something that shoots the surface and excavates a crater.

IRA FLATOW: So this is not like a Mars Rover that we put up. These are little hoppers. Explain what that means.

BRUCE BETTS: So they’ve got different sizes, but they range from kind of twice the diameter of a hockey puck but a similar shape, which is what they’ve deployed two of that are on the surface now up to about a large shoebox size that’s called Mascot. That’s from the German space agency, along with the French.

Basically, you’ve got this really low gravity of the asteroids, so wheels won’t get any traction. And if they do, you might end up launching yourself off never to come back. So they have things inside the spacecraft, like a turntable inside one of them, that they rotate rapidly. And that causes a torque that flips the hopper up, and then it floats sort of and comes back down in a few minutes and the low gravity up to 15 meters away.

IRA FLATOW: It’s like what you do when you ride your bike. You get the bike wheels spinning, and it creates torque in a different direction.


IRA FLATOW: And that’s how they’re getting around on the asteroid. How big is It What did they want to learn there?

BRUCE BETTS: So the asteroids about a kilometer or half mile in diameter, and it’s what’s a so-called sea type asteroid carbonaceous. In other words, it’s got more and more carbon-rich than other asteroid types, and we think it’s one of the most primitive types of asteroids. So it’s really a leftover from solar system formation. So what they want to study, among other things, through sample return and through the landers is not only what this asteroid is like but also to extrapolate– particularly regarding the carbon-rich materials, the organic materials, and also water hydrated minerals– basically to understand what the implications are for the early formation of the solar system of the Earth, including the building blocks of life and they came to Earth in terms of carbon molecules and water.

IRA FLATOW: How is the JAXA approach, the Japanese approach, to missions different than the American NASA plans for their missions?

BRUCE BETTS: They have a lot of similarities, and the others– they’re doing a lot of testing and trying to ensure mission success. In this case and in some cases, the Japanese missions will add some additional experimental technology– perhaps more than NASA does on average. It varies mission and mission. So having these hoppers, having a deployable mechanism that fires a bullet at 2 kilometers per second into the asteroid to expose material underneath, having a little free flying camera that takes a picture that all the main spacecraft hides behind the asteroid– all of these are more high risk but not necessarily mission risk activities that they’ve come up with. And they’ve done it in previous missions where they come up with the basic mission plus fun gizmos to test out.

IRA FLATOW: I always like those fun gizmos. This is “Science Friday” from WNYC Studios. That’s terrific to hear about that. Here to tell us more about that Hayabusa 2– I want to thank you very much, Bruce, for taking time to explain all this stuff.

BRUCE BETTS: Oh, my pleasure.

IRA FLATOW: Bruce Betts is chief scientist at the Planetary Society in Pasadena, and Hayabusa 2 was expected to deliver the asteroid samples back to Earth in late 2020. But for scientists who want to study asteroids before that time or need more than just a few handfuls of samples, what are they supposed to do? Well, you can cook up your own asteroid. That’s the subject of our latest Macroscope video. You can watch the video on our website sciencefriday.com/cookingasteroids. And Luke Tarascan our video producer’s here to tell us the recipe. Hey, Luke.


IRA FLATOW: It sounds like a very fun video.

LUKE TARASCAN: Yes, it’s a little bit between somewhere between asteroid science and cooking. It’s cooking video.

IRA FLATOW: It’s a do-it-yourself recipe. What’s in your recipe for cooking?

LUKE TARASCAN: Well, Ira, you ever baked an apple pie?

IRA FLATOW: One of my favorites.

LUKE TARASCAN: Have you ever baked a $2 billion apple pie?

IRA FLATOW: No, I don’t have that budget.

LUKE TARASCAN: Most people don’t, but NASA kind of does– well, when you consider that their pie could be an asteroid sampling mission or like JAXA’s recent mission. And before you do that, you want to test out all this gear. And in order to do that, you need to make sure that you’ve got good flour, good crust. And in this case, you’re dealing with asteroid simulants.

So there’s a startup in central Florida called Deep Space Industries, and they cook up asteroid simulants. They use basic minerals. They put them through mixers, and they bake them exactly like cooking. And they produce simulants that scientists can use to test their equipment.

IRA FLATOW: We know what our ingredients should be if they’re making a pie. How do they know what ingredients to put into this?

LUKE TARASCAN: Well, they don’t know for sure because there hasn’t been any missions to these asteroids to get it. But they do have meteorites, and they can look at the consistency of the minerals inside the meteorites. And then they can also use data from NASA and ESA and JAXA to get an estimate of how much carbon, how much water, how are these asteroids put together, and then they can bake it up, and then have a recipe.

So the University of Central Florida actually puts out these recipes, and you can actually see what they think is inside these asteroids. You know I always ask this question, don’t you? You know it’s coming up. Oh, yes, can you do this at home?

Well, you could do this at home if you had cement mixers. You had several microwaves that you’re willing to destroy with hours and hours and hours of microwaving minerals. If you had a drying room, a lot of time, and an really, really, really enormous pressure cooker, which they called the Cronstadt type bomb because the Cronstadt type bomb because they thought it could explode at any given time.

It didn’t explode, but they cooked up some minerals that were some of the rarest on Earth using the special pressure cooker. So they can use this to test out space mining, for example. You’re saying this is a test. If you want to an asteroid and we don’t know what it’s made out of, you can make this recipe and fool around with it yourself.

LUKE TARASCAN: The ultimate goal of deep space industries is space mining is to basically harvest asteroids so that you can make rocket fuel or a nice habit space house or all sorts of materials that you could use because it’s cheaper to space mine than it is to launch all that stuff into space. But before you can do that, you have to know what’s in those asteroids. And before you do that, you have to practice.

IRA FLATOW: You have to practice. Yes, that’s what your mother and my mother told us exactly. That’s how we’re getting to Carnegie Hall.


IRA FLATOW: All right, Luke Tasrascan, our video producer. And you can watch his latest Macroscope video on our website at sciencefriday.com/cookingasteroids.

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