Pieces of Mars: How We’ll Get Them to Earth

Mat Kaplan: How we will get Mars rocks to Earth, this week on Planetary Radio.

Mat Kaplan: Welcome. I'm Mat Kaplan of the Planetary Society with more of the human adventure across our solar system and beyond. If it was easy, someone would've done it already. It's not. It's really, really hard, but we're now closer than ever to achieving that long held goal for robotic exploration of the Red Planet. NASA JPL's Richard Cook is the manager of the Mars Sample Return Program. He'll share the current plan, including how two descendants of Ingenuity, the Mars helicopter, may play key roles.

Mat Kaplan: Here are a couple of program notes. I'll soon be leaving for the Kennedy Space Center where I'll join the hopeful crowd, watching the first launch of the Space Launch System. That biggest ever rocket will boost the Artemis 1 Orion capsule toward lunar orbit. It's sitting on the pad as I record this with everything looking A-OK for liftoff. Yeah, we really used to say A-OK. Bruce Betts has come up with a humdinger of a space trivia question based on the SLS. You'll get your shot at it in this week's What's Up.

Mat Kaplan: While I'm away, you'll get to hear the celebration of the Voyager mission's 45th anniversary. I'll be at JPL when deputy project scientist Linda Spilker and others mark this occasion. You'll hear my coverage in our August 31st show that will also feature another conversation with the great Ann Druyan. Ann and I will talk about the Voyager interstellar mission and those golden records she helped create.

Mat Kaplan: Turning to the Downlink, the Planetary Society's free weekly newsletter means we're also turning back to last week's visit with Jane Greaves and our conversation about phosphine and the possibility of life in the atmosphere of Venus. Thanks so much to all of you who took up the challenge Jane and I gave you. We've received a bunch of very entertaining and even beautiful artists' concepts of those penguins who fly high above Venus. Need I remind you that there is no actual evidence for penguins or any other living organisms there, but reviewing your fanciful artwork has been great fun. We'll have more to say about it next week, and we'll share some of those images. There's much more at planetary.org/downlink, including the latest news about Virgin Galactic.

Mat Kaplan: Richard Cook has been in the Mars exploration business for more than three decades. He worked on the Pathfinder mission that brought the tiny Sojourner rover to the Red Planet just over 25 years ago. He became project manager for the Mars exploration rovers, Spirit and Opportunity, and did the same for the much more ambitious Curiosity Mars Science Laboratory that is still rolling and doing science. He joined us on stage back in 2012 for a Planetary Radio live discussion about that mission. You can hear it on this week's show page or planetary.org/radio.

Mat Kaplan: Richard left his job as JPL's associate director for flight projects and mission success in 2021 to take on Mars Sample Return. As you'll learn in our new conversation, it has been an exciting homecoming. Richard, it's been a long time. Welcome back to Planetary Radio.

Richard Cook: Thank you. It's great to be here.

Mat Kaplan: Do we now have a pretty good idea of how those priceless pristine bits of Mars that Perseverance is collecting are going to make their way back? Not back, are going to make their way here to Earth, to all those eager scientists who just can't wait to get them in their labs?

Richard Cook: We do. We're in the part of the phase of the project where we're still formulating our plans. Everything hasn't been approved, but I think we have a good technical concept for how we want to do it now. And I think we're ready to move on into making that happen.

Mat Kaplan: Let's talk about some of the details of that. I mean, this phase that NASA just talked about, there was a press release put out. It said, "It's the system requirements review," but are we still in what you're calling the conceptual design phase?

Richard Cook: We are, right. Officially, we're still waiting for, as I said, all of the approvals to take place, but we are in broad terms in the formulation phase of a program which is broken into two main chunks. One is the concept phase. And the second part is the preliminary design phase. And so we're actually about to go from concept design to preliminary design and that'll be kind of the next year or so.

Mat Kaplan: This is still such an exciting step, to actually have seen that press release and seen the artist renderings of the spacecraft that are going to be doing this work for us. I mean, it seems like maybe Perseverance was the first real feeling we got, like this long-held dream sample return. It's actually started, and now this just seems like the next step along the way.

Richard Cook: Absolutely. And it's funny, because I've been here 30 years and worked on several sample return concepts or ideas and they just never got past a certain point. And I think we really are sort of now at the point where we're going into terra incognito, for example, on a sample return, right? Where we really haven't made it this far, and of course, we have on other programs. So we certainly know what that feels like, but it's really refreshing and a great feeling to get the sense that, yeah, the momentum is building and we really have a concept that can be executed. And now we just need to start going down that path.

Mat Kaplan: So what would that be on Mars? Aries incognito or [inaudible 00:06:05]?

Richard Cook: Yeah, there you go. Yeah, good point.

Mat Kaplan: So there are some big changes here from what we originally thought would happen. Maybe the biggest one, correct me if I'm wrong, is that that rover that we were hoping to have provided by the European Space Agency for a number of reasons is now no longer part of this plan. Do I have that right?

Richard Cook: That's right. I think it's a little bit of a confluence of several different events that made that possible. First and foremost, of course, is that Perseverance is doing so well on Mars that it really has kind of exceeded, I mean, knock on wood, exceeded everybody's expectation in terms of how well it's worked, the samples it's gotten have been very compelling so far. The vehicle itself is working great. The team is doing a tremendous job.

Richard Cook: And so it really gives you confidence and gives us confidence that we can count on it to be the principle path, right? We always knew it would be there, we'd likely would be there, but our confidence has only gone up over time that it would be able to be the primary delivery path. So that's one item. The second one, of course then, is we started talking about, well, do we need a backup? And clearly for a long time, the Fetch Rover and Perseverance were sort both able to do the job, but having the second rover, the Fetch Rover, does make the program more complicated. It adds another ... I mean it's a very capable vehicle, but it takes up space and it requires resources on both sides of the Atlantic to make it happen.

Richard Cook: And I think given our confidence in Perseverance, we said, "Well, maybe we should look at other options for that." And that's what we've been kind of doing for the last year is, are there other ways to both get the Fetch Rover there, but also fulfill its function, which is to sort of serve as a second path. And in the end, again, success of Ingenuity on Mars has really opened up the possibility that a helicopter, an aerial-based system, could achieve that same retrieval recovery function with a much smaller footprint. Much more straightforward way of ... I mean, it's still challenging to accommodate a one meter blade, right? But in general, the mass of the helicopter's very low and so they're much easier to bring along than a Fetch Rover would be.

Mat Kaplan: So no Fetch Rover. Still, of course, a lander, a NASA-provided lander, which we can talk about more in a moment. So instead of the Fetch Rover rolling over to where Perseverance happens to be, or maybe the two meeting in the middle. Now Perseverance, you might hope, will roll over to this lander. Or if for some reason, Perseverance can't, you'll have not one, but a couple of helicopters to help transfer those samples?

Richard Cook: That's right. Yeah. I mean, the prime path is exactly what you said. Perseverance will drive literally right up to the lander, and the lander, of course, has an arm on it. And the arm will reach out and one at a time pluck the samples that Perseverance is carrying on it and take it off. Take each sample tube off one at a time and put it into what we call the orbiting sample canister, the OSC. It's the thing at the front of the MAV. It is our carrier, our test tube rack, so to speak, of where we put the tubes. And so, yeah, that's the basic idea, is Perseverance is right up close to where the lander will be.

Richard Cook: The other possibility is exactly what you said, that for whatever reason, over the next six, seven years, we decide that Perseverance is not able to keep going, or we don't want to gamble that it will continue to survive. Then we can drop all of the sample tubes that it's carrying with it on the ground. And in fact, we're going to do that for the first time in probably the October, November timeframe where we're going to establish a first sample depot. And this has been the plan all along where we're going to ... Once Perseverance gets a certain number of high-value, interesting samples, it drops a set of them, 10, 12, in that range, in a really safe, really benign place. And then it can go on and do the rest of its mission, and it can continue to get more samples.

Richard Cook: But we know that we have, at that point, no matter what happens to Perseverance after that, we know we have this set of predeposited sample tubes. If, for whatever reason, Perseverance were to die six months from now, which we think is, of course, unlikely, very unlikely we could in fact send the lander there. And then you're right. The helicopters would go and retrieve those 10,12 sample tubes and bring them back to the MAV. And that would be it, that would be good. From the scientist's perspective, they wanted to go to Jezero Crater as this most exciting place they could go to on Mars. And they're very clear to us, if you can only bring back those 12 tubes, "Okay. I mean, that's great. That's good enough." I mean, if you can get more super, even better, right? But they're definitely would be willing to go with, in a pinch, with the first set of 12 samples

Mat Kaplan: I hadn't had this image in my head before, but of Perseverance dropping those samples, almost like laying the world's most precious golden eggs to be retrieved later. You mentioned the MAV, the Mars Ascent Vehicle. I'll come back to that in a second. But the first thing I got to mention is we've been following and talking now and then to members of that team behind Ingenuity. They must be justifiably proud to see that the success of their little proof of concept whirly bird is now helping to shape plans for sample return.

Richard Cook: Absolutely. And the helicopter team, I mean, there's a whole sort of backstory to Ingenuity and sort the little helicopter that could. And it was part of this bigger ... I mean, in a lot of ways, it reminds me at least of the Sojourner and Pathfinder era where it was sort of the group of people that no one believed in. And they're off in their corner doing their thing. And then in the end, they've got this dramatic success. And it really sort set the stage or laid the groundwork for future use of mobility, aerial mobility on Mars.

Richard Cook: And sure enough, the first thing out of the gate is, "Well, hey, we could use this to retrieve samples." And so some of the people that ... Bob Balaram was sort one of the engineers here who was the father of the helicopter of Ingenuity, for lack of a better word. He's very much in the mix here as saying, "Hey, this is where go from here." And so it's a testament to the both ingenuity of the folks involved, but also their perseverance, because they're very much like, "We believe in this technology and we're going to make it useful on Mars for future missions."

Mat Kaplan: Ingenuity and Perseverance-

Richard Cook: There you go. Exactly.

Mat Kaplan: ... those titles become even more appropriate than when they were chosen years ago now.

Richard Cook: Right.

Mat Kaplan: You've got this lander, which at least in the artist rendering, I thought I see a little bit of heritage there of here's my coffee cup with Insight logo on it.

Richard Cook: Yep. There you go.

Mat Kaplan: I mean, there's some proven technology, right? But I'm also thinking of that MAV, that Mars Ascent Vehicle rocket, the one that's going to carry the samples up to the waiting Earth Return Orbiter from the European Space Agency. I am trying to imagine a more harrowing step in this process. It seems like seven minutes of terror in reverse.

Richard Cook: It is. And I think that, I mean, I hate to say that we've gotten a little blase about landing things on Mars, but it is as you said. I mean, it's very similar, very much the same problem, and in reverse. I do think that, I mean, clearly we have technology here on the Earth that we're relying on as a starting place, the propulsion, the thrust vector control, all of the elements, right? But putting it all together and demonstrating it for the first time on the surface of Mars carrying these, as you said, very precious, precious cargo.

Richard Cook: I mean, we have to be conscious of the fact that's probably the biggest challenge we have is to make that piece of the program work. It is good that we have so many people helping in that regard. So it's not like we're just trying to do this as an experiment. You know, we got Marshall, we got Lockheed Martin, we're Northrop, we've got all of the people who really understand how to make systems like this work, working together with us. And I think that gives us confidence that we've got the right approach.

Mat Kaplan: So that little rocket makes it up into orbit and there it meets ... Tell us about this ISA contribution.

Richard Cook: Well, so that one of the things that I always laugh about with these programs or think about is that how many kind of amazing things happen that you don't think about. Like in this case, well, first we have to land this thing. Then we got to take off and have the MAV work. But rendezvousing with a volleyball sized sample canister with a spacecraft that's the size of what about a football field? I mean, the solar arrays on this thing are huge. And so, it's got to find and then rendezvous with this fairly small basically ... I mean, it has a beacon on it, but is obviously it's not a full spacecraft. It's a very simple sort of beacon. And the ERO guys have to basically find it, close on it, and then get in a position where it can get ingested into the CCRS system, the capture and containment system.

Richard Cook: And so all of that is ... Fortunately, there's a lot of similarities between that and rendezvousing with stuff here on the Earth. And so there's a lot of technologies and techniques both to identify it, because you're using optical and RF systems to try to see where the OS is. But then the whole closed-loop guidance and control of how you rendezvous with something and it's all done autonomously, right?

Mat Kaplan: Yeah.

Richard Cook: Because we can't really do a joystick upon approach. And so that's a challenging problem. And I think fortunately the ERO team, the ESA [inaudible 00:16:56] leadership with Airbus in Toulouse, they have a lot of experience, a lot of ability to get access to sensors. The [inaudible 00:17:05] is building the camera and the lidar is from Europe as well. And so they're really putting their best effort on that part of it because that's so critical to, obviously, the full success of the program.

Richard Cook: CCRS, I mentioned, that's the next part. And that's, again, in the next category of, "You're doing what?" is, once you get this thing, get it close to where you're ready to grab this, the volleyball, then CCRS has to ingest it, has to keep it from flying back out, right? So I mean you got to keep it captive and then you have to go through a series of on orbit assembly activities, because obviously one of the big requirements we have is that we need to make sure that the whole sample canister is contained in not one or two, but basically three successive shells that are there to protect it from all of the reentry dynamics that we'll see when it comes back to the Earth.

Richard Cook: And so in order to meet the planetary protection requirements, we have to ensure that no Mars dust, our samples, are potentially on the entry vehicle. We have to go through this effort to encapsulate multiple times. Each of those, the OS, gets encapsulated two or three times. And then finally it gets put in the EEV, the Earth Entry Vehicle, and brought back to the Earth. So that itself is not something we've ever really done either is an autonomous onboard assembly of multiple hardware elements to encapsulate. I mean, to some extent, OSIRIS-REx, and Genesis, and Stardust did that, but much, much simpler than what we're talking about doing.

Mat Kaplan: So you've pretty much answered my next question, which was about this sophistication of the robotics and other technologies that are going to be needed to make all of this happen. I mean, really, it makes me think that this is at least in some ways, the ways you've described, the most sophisticated and audacious attempt of any robotic mission.

Richard Cook: It is in the sense of the need for the encapsulation and the assurance of that encapsulation. The one thing that it doesn't do that makes it in some ways comparable ... On Perseverance there's the other end of the spectrum, which is the sampling system. It's doing a bunch of those same things as well, where it's getting tubes and doing all that. But it has the challenge of also having to do that within Mars rocks. You got to have a drill. You got to know that it's interacting with Mars materials. So the actually closest analogy, we think, to CCRS is really the sampling system on Perseverance, which was a very substantial challenge.

Mat Kaplan: Robot inside the robot, right?

Richard Cook: Exactly, that's right.

Mat Kaplan: And we always tell people, find a description of this sample system that's inside Perseverance and you will be blown away by its complexity, but it's working.

Richard Cook: Yeah. That's the most challenging part of Perseverance, really, is that piece because the rest of it had a lot of heritage from ... It's not to make it seem easy, but it had heritage from Curiosity or from sky crane system on Curiosity. But the really new new thing on Perseverance was the sampling system. Fortunately, some of the people that worked on that are now working on CCRS, because it's a joint ... It's led by Goddard, because Goddard has a lot of on orbit assembly experience from Hubble and other places like that. And so it's mirroring them, their history and ours, in terms of sample handling and things like that. And so it's turned out to be a great collaboration between the two centers to make this system work.

Mat Kaplan: The other big collaboration that we've already mentioned is with the European Space Agency, which seems to be ... I mean, I don't know if it was Thomas Zurbuchen, or maybe the administrator, was talking about the benefits of a program like this, as so many are nowadays, between NASA and agencies around the world. What these kinds of multinational collaborations bring to a project like this, I mean, it's made it a lot easier to take this on, hasn't it?

Richard Cook: It has. Yeah. And the pieces that, I mean, even without the Fetch Rover, the pieces that the Europeans are doing like ERO and the sample transfer arm, we couldn't do this without them. I mean, those systems are very complex. They require access to industrial capabilities that, to be honest, we have, but we're also making use of. So we really need to ... These projects get to be so big and complicated that you either take 30 years to do them, or you got to figure out a way to get help and to get partners.

Richard Cook: And that presents a challenge because, I mean, everybody has different cultures and different ways of doing work, but I think we've built a really effective sort of teaming relationship with the Europeans where, I mean, they're totally in. And they're very invested in making sure that they bring it to bear all of the good things they do. They're also want to learn how we do things and vice versa. I think it's been great experience for us to understand how they do projects as well. Because it really does make you conclude that there's so much capability out there if we could all just work together. And this is a great opportunity to demonstrate that.

Mat Kaplan: Yep. If all goes well, what are we looking at? I mean, it looked like maybe the Earth Return Orbiter will be launched before the sample return retrieval lander. And if so, why is that? Why is the orbiter going first?

Richard Cook: Mostly so that it's pre-positioned there. It takes a little bit longer for it to get there because the job of going to Mars and coming ... This is the first time we've ever sent something to Mars and then brought it back. And for just the size of the spacecraft, the amount of fuel you have to take, all results in ERO both being very large, but also requiring an electric propulsion system to get it there and to get it back. And so EP systems tend to be ... It takes longer to get there because low thrust. So it takes a little bit longer to get there.

Richard Cook: We want it to be pre-positioned so that it can help with relay, to serve as a relay for the lander. When the lander lands, it's got basically a little less than a year to get everything done and that's a lot of work and we want to make sure that the there's relay and we obviously have relay satellites there now. They're getting a little bit long in the tooth, so to speak. And so we were worried that, would they still be there? And so we want ERO to be in a position where it's already there, already ready to do the relay function when the lander gets there.

Richard Cook: The lander, it's interesting, is actually spending more time getting to Mars than it normally would do because we want to have it land at the right time of year. The lander itself is solar powered and there's a lot of reasons for that we could go into, but the the lander and the helicopter are both solar powered. And so we wanted it to land in sort of spring, for lack of a better word, on Mars. So because of that, the the lander is taking kind of a little bit of a circuitous route to Mars as well. And that's why, even though we're launching in '28, we won't actually get the lander to Mars until 2030. So it takes a year longer than normal to get there. Then it does the year on the surface, then the MAV launches and ERO catches the OS. And then at that point, because again, it's electric compulsion, it has to spiral back out and head back to Mars. And so by the time it spirals out and gets back to the Earth rather, it's about 2033, late 2033.

Mat Kaplan: So 2033 is when we might see, if all goes well again, that sample return capsule making its way blazing through the sky and being recovered down here on the surface.

Richard Cook: That's right. And that's when all the scientific analysis can begin, right? The Perseverance team has done a great job picking a great set of samples, and now they're going to have to be patient. The science community's going to have to be patient while we go get them and come back. And then they finally can take a look at them and actually get them in their labs and start looking at them.

Mat Kaplan: I clearly don't have to tell you how long this has been the dream, the holy grail, not just for engineers, but for those scientists that you're talking about, to get those samples back into the labs with their big hulking equipment. You've been a JPL, as I counted, for about 33 years.

Richard Cook: That's right.

Mat Kaplan: Did you know that there is a page about you on the NASA site that was created while you were still the flight ops manager for Mars Pathfinder?

Richard Cook: I'm not surprised because nothing ever goes away on the internet.

Mat Kaplan: Yep, yeah. Let me give you a quote from that page. So here it is, this is back when you and I both had a lot more hair. "One day I hope I can work on a sample return mission that will bring back a rock for geologists to look at."

Richard Cook: There you go.

Mat Kaplan: Dream come true?

Richard Cook: Absolutely. Yeah. Well, I mean, this job really is the culmination of my career. I mean, I've worked on Pathfinder and with Curiosity, Spirit and Opportunity. So I've had several missions here and there were opportunities to go do other things. I worked up in the director's office for a while and did other stuff. But the chance to actually get to where the apex of the whole Mars program for the last 30 years, where we can actually make it happen is just ... It's such a great opportunity despite the everyday challenges, I really cannot say enough about what a great opportunity is.

Mat Kaplan: Richard, I hope that we are still following this, you and I, and ready to be part of that joyous reception in 2033, when those bits of Mars come to Earth.

Richard Cook: There you go. Me too, looking forward to it.

Mat Kaplan: Thank you so much.

Richard Cook: Thank you. Have a good one.

Mat Kaplan: That's Richard Cook of the Jet Propulsion Lab, manager of the Mars Sample Return Program. I'll be right back with Bruce and What's Up?

George Takei: Hello, I'm George Takei. And as you know, I'm very proud of my association with Star Trek. Star Trek was a show that looked to the future with optimism, boldly going where no one had gone before. I want you to know about a very special organization called the Planetary Society. They are working to make the future that Star Trek represents a reality. When you become a member of the Planetary Society, you join their mission to increase discoveries in our solar system, to elevate the search for life outside our planet, and decrease the risk of Earth being hit by an asteroid. Co-founded by Carl Sagan and led today by CEO Bill Nye, the Planetary Society exists for those who believe in space exploration to take action together. So join the Planetary Society and boldly go together to build our future.

Mat Kaplan: It's time for What's Up on Planetary Radio. The chief scientist of the Planetary Society is here. Please help me welcome Dr. Bruce Betts. Yay.

Bruce Betts: Thank you. Thank you. Good to be here. Nice to meet with all of you wonderful people.

Mat Kaplan: Will indulge me? I'm going to read a couple of comments. I continue to get these wonderful comments from people about my plans. Still have more than three months, folks, before this happens and you'll still hear from me now and then. But Stephanie Retrum in Arizona, "I'm thankful to Mat for all these years of joy and laughter and gracious humility. What a loss. I wish you all the best in the future. Wednesday is my favorite day because of you." Isn't that nice?

Bruce Betts: Wow.

Mat Kaplan: I know.

Bruce Betts: You wrote that one, didn't you?

Mat Kaplan: No, no. And I didn't pay her, at least not yet. Vlad Bogdanoff in British Columbia. "Mat, I'm so terribly sorry to hear of you're impending retirement. You and your voice will be immensely missed. In your honor, I will continue my Planetary membership in perpetuity until the inevitable heat death of the universe."

Bruce Betts: That's kind of a good news/bad news.

Mat Kaplan: That's good until entropy wipes us all out. Yeah.

Bruce Betts: Stop bringing me down. Stop, be more gracious.

Mat Kaplan: Here's one that I think you'll like, Ian Jackson in Australia. "I was wondering that if Bruce would take one of his original, highly prized, McDLT burgers from the freezer, defrost it, open up both components. Would the smell be quite similar to Comet Gerasimenko?

Bruce Betts: Wow. I think we've got ... Oh, there's definitely internal publication in that. Thank you. Thank you. I usually just put a clothes pin, which is hard to find these days, clothes pin on my nose and eat them straight out of the freezer. So I really don't ... Except I heat up the hot side.

Mat Kaplan: Not a dirty snowball, a dirty McDLT. That's what we're talking about.

Bruce Betts: Was there ever a clean McDLT? I don't know.

Mat Kaplan: Good point. What's up?

Bruce Betts: Oh, you get me so frazzled. We got planets across the night. So we've got Saturn up when the sun sets in the east, and then coming up a couple hours later, Jupiter. And in the middle of the night, Mars coming up, and then Venus. Venus is going to be tough, but it's trying to hang on for another couple weeks low in the east in the predawn. Fun thing to look for is Mars, which is coming up, again, kind of middle of the night but it'll be up in the predawn, is hanging out for the next several days near the reddish star Aldebaran in Taurus. So you got red and red sort of, Mars is getting brighter and brighter until its closest approach in December. And so it is actually significantly brighter than Aldebaran right now, check that out.

Bruce Betts: We go on to this week in space history, it was big week. 1962, Mariner 2 launched to Venus 60 years ago. Voyager 2 had two big weeks. One in 1981 this week in space history flying by Saturn and one in 1989. It's still the only spacecraft to fly by the Neptune system. We move on to random space fact.

Mat Kaplan: I think you found a unique approach there.

Bruce Betts: So hard these days. That was my impersonation of the SLS rocket doing random space fact.

Mat Kaplan: Let's hope it happens on Monday the 29th.

Bruce Betts: Let's hope. So it's scheduled to launch soon, NASA, most powerful rocket out there when it comes online in a few days, hopefully. Interestingly, it is so powerful. How powerful is it? It's so powerful. It can lift more cargo to the moon than the Space Shuttle could lift to low Earth orbit.

Mat Kaplan: Wow. I'm also upset because you took my line, how powerful is it?

Bruce Betts: I'm sorry. I got excited. We can rerecord it if you want?

Mat Kaplan: No, no, no. It's quite all right. You did a nice rendering of it, but that is quite amazing. Very much more powerful at least than the first stage of the Saturn V. It's just ... I expect to be knocked over.

Bruce Betts: I hope you're knocked over. Have someone video that.

Mat Kaplan: You want to watch?

Bruce Betts: Yeah. All right, let us go on to the trivia contest. And as usual, there is something complicated that I hadn't considered brought up by one of our listeners, but let's start out with the question I asked you. What spacecraft first lifted off the surface of another world beyond Earth. And I know kind of how we did Mat, but tell us more.

Mat Kaplan: I will. As you know, about half, maybe more, of the entries that we got this time said Apollo 11.

Bruce Betts: Gotcha.

Mat Kaplan: Bob Clay in Arizona, he's not our winner. Sorry Bob. "Oh Bruce, you are a tricky man and a mad scientist. Everyone is going Apollo 11's Eagle. Nope. It was Surveyor 6. It used its liquid-fueled Vernier engines to lift itself from its original landing site to a position 10 feet away, little hop." He says, "Would that make Surveyor 6, an honorary pioneer? It didn't ranger about the surface, like Curiosity. It jumped more like a space flea." And then before you comment, John Geiten in Australia, "Tricksy hobbits."

Bruce Betts: Tricksy hobbits.

Mat Kaplan: Yeah, that would be more like it, that'd be more like it. Are they right? I mean, was that what you were looking for?

Bruce Betts: That is exactly what I was looking for, the Surveyor 6. They did the test to lift off and land again and they did it successfully.

Mat Kaplan: We also got this entry from Steven Sourwine in Idaho about Surveyor 3, which apparently inadvertently lifted off the moon twice due to its engines not shutting down properly on landing. Now to me, that's just a rough first landing. It just bounced a little bit trying to get down the first time. Do you disagree?

Bruce Betts: I am neutral. I would've awarded it to him, and it's taught me something. So thank you. But no, it's certainly ... If I knew about it, I would've said intentional liftoff, but any case, my understanding is that did not come up as a conflict in the random.org choice. But it is an interesting tidbit. Yeah. Rough landing. We've all had some of those.

Mat Kaplan: Indeed. Your understanding is correct, sir. Our winner, he is a long time listener, Torsten Zimmer in Germany. It's been three and a half years since he won one of these that was decided by random.org. He actually did win one of our sort of skill-based ones a couple of years ago, but still Torsten, congratulations. You are going to get that copy of The Astonishing Story of the First Human to Leave Our Planet and Journey into Space by Steven Walker. It's a story of Yuri Gagarin. We can give that away. It's a quite a story. It has great illustrations, photos, included in the book. Have fun reading it.

Bruce Betts: Excellent. Would you like a question for the future?

Mat Kaplan: Yeah, what the heck.

Bruce Betts: Coming back to SLS, listen carefully. As scheduled, as planned, on the first four SLS missions, first four flights of the rocket. How many of the main engines have already flown as part of a rocket launch? Albeit prior to adaptations made for SLS. So there are other gizmos hooked up, but how many of them, of the main engines, how many of them flew before? Figure that one out and had to planetary.org/radio contest.

Mat Kaplan: Wow. Across all four?

Bruce Betts: Across all four. Otherwise, it would just be trivially easy. Yeah, I'm kidding. But no, across all four.

Mat Kaplan: Start your work folks. Start your engines. You've got until August 31st. Wednesday, August 31st at 8:00 AM Pacific Time. And here is the prize because we have these great books that we can still award. This is Totality! by our friend, Jeff Bennett. It is what it sounds like. It's a book about total eclipses. It's really well done. He did a great job with this. It's almost ... It's a little thin to be a coffee table book, but it's that kind of format. Lots of great illustrations. We will send it along to the winner with Jeff's compliments, and I think we're done.

Bruce Betts: All right, everybody go out there, look up the night sky and think about the concept of reusing your car engines in the next car that you drive. Thank you and goodnight.

Mat Kaplan: Well, the first motorized vehicle that I owned was a Honda 175, 175 cubic centimeter engine. I think it might be a little bit underpowered for ... Well, how many of those would you have to put in the SLS to get it to the moon? A lot.

Bruce Betts: Yeah. You went a different direction with reusing car motors and rockets.

Mat Kaplan: Oh, cars, cars. I get it.

Bruce Betts: Cars, yeah.

Mat Kaplan: He's Bruce Betts, the chief scientist of the Planetary Society who would know better than to make a mistake like that when he joins us here for What's Up? Planetary Radio is produced by the Planetary Society in Pasadena, California and is made possible by its Martian members. You earthlings are also invited to become one of us at planetary.org/join. Mark Hilverda and Rae Paoletta are our associate producers. Josh Doyle composed our theme, which is arranged and performed by Pieter Schlosser. Ad astra.