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Season 4, Episode 4: Persevering on Mars, with Mitch Schulte

Season 4Episode 4May 1, 2020

NASA’s upcoming Mars Perseverance rover, scheduled to launch in July, is bringing a set of technologies to explore the Red Planet in new ways. Mitch Schulte of NASA Headquarters discusses this mission and the effort to explore whether Mars had life in the past, or even now

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Mars has long been the subject of fascination among those who have ever wondered if there is life beyond Earth. NASA’s upcoming Mars Perseverance rover, scheduled to launch in July, is bringing a set of technologies to explore the Red Planet in new ways. The rover will search for signs of ancient microbial life on Mars in the astrobiology portion of its mission. Perseverance will also characterize the planet’s climate and geology, collect samples for future return to Earth, and pave the way for human exploration of the Red Planet. Perseverance is also bringing a helicopter named Ingenuity to test out aerial flight on another planet for the first time. Mitch Schulte of NASA Headquarters discusses this mission and the effort to explore whether Mars had life in the past, or even now.

Jim Green: We’re going to Mars, and we’re taking with us this huge rover called Perseverance.

Mitch Schulte: One of the interesting things that Perseverance is going to do that none of the rovers has ever done before, is collect rock samples. And we’re working on plans to bring those rock samples back.

Jim Green: Hi, I’m Jim Green, NASA’s chief scientist. And on this season of Gravity Assist, we’re looking for life beyond Earth. Let’s follow the Perseverance rover going to Mars and find out what it can tell us about that.

Jim Green: I’m here with Dr. Mitch Schulte, and he is the program scientist for the recently named Mars Perseverance rover. So today, we’re going to talk all about this fantastic rover, and what it might tell us about the habitability of Mars today, and perhaps in its past. So welcome, Mitch, to Gravity Assist.

Mitch Schulte: Thanks, Jim. Great to be here.

Jim Green: Well, Mitch, we had Spirit and Opportunity, then Curiosity. Now we’ve got another one, Perseverance. Why a new rover?

Mitch Schulte: Well, Jim, every time we go to Mars, we learn something new. And what we’re really trying to establish on Mars is whether there was life there in its ancient past. Early in Mars’ history, we know that it was a warmer and wetter climate, as we see from this evidence of liquid water on the surface. So now that we’ve established that there was liquid water early in Mars’s history, we think that it could have been habitable, like Earth was and is now. So we really want to get after this idea of establishing what kinds of places on Mars were habitable and whether life actually did get a start on Mars.

Jim Green: Yeah, so let’s go to a place where we know water existed in its past on Mars.

Mitch Schulte: Right. And so that’s one of the reasons that we’re going to Jezero Crater,

Mitch Schulte: J-E-Z-E-R-O. This is actually a crater that was once filled with a lake. And it’s in a really ancient part of Mars about three-and-a-half billion years old.

Jim Green: So this is really a neat place. We want to go to a lake because of why? What’s the significance of that?

Mitch Schulte

Mitch Schulte: Well, for one, lakes of course contain water, liquid water, and we think early in Mars’ history, this area of Jezero Crater, which is now dry, there’s no liquid water in it now. But there’s evidence in the rock record that there was a liquid water lake there, three-and-a-half billion years ago. And everywhere we go here on Earth, where we have liquid water, we find life.

Jim Green: Yeah, that’s right. This makes it a really fantastic area. In fact, the whole area around it looks like a delta, which is where flows of water have occurred, flowing into the ancient ocean of Mars. And that makes it another really exciting place. If life started in an ocean here on Earth, maybe it started in an ocean on Mars, and then moved to the land.

Jim Green: Well, you know, Perseverance is set the launch from Kennedy Space Center on July 17th. That’s when the window opens. So our highway to Mars opens up, we have about a month and off we go. So how long does it take for us to launch Perseverance and get it to Mars?

Mitch Schulte: Of course, we have these windows for a reason. And in the case of Mars, it’s when Earth and Mars are relatively close together. So we want to make sure we hit that window so that we take the least amount of time and the least amount of fuel to get the rover there. So launching on July 17, we have about [a] three week period when we can launch. July 17 is the first day of that period. Regardless of what day we launch during that period, we will land on Mars on February 18, 2021. So it’s about a seven-month trip.

Jim Green: So, what are we looking for in terms of the rock record?

Mitch Schulte: Well, we’re looking for a bunch of different things. Obviously, the very interesting part would be looking at rocks that might have been deposited or influenced in some way by the presence of life. The other really interesting thing is we want to actually be able to date these rocks. And so we’re looking for some lava flows or some igneous materials that will tell us the exact age of the deposits that we’re seeing. The really other interesting thing about this delta is that deltas here on Earth are real good places where we see deposits of fine grain material grading all the way up to some coarser grain kinds of sandstone. And in those deposits, we often find evidence of organic matter. And if there was life on Mars and producing organic matter, we might expect to find that in the deposits in the delta.

Mitch Schulte: One of the interesting things that Perseverance is going to do that none of the rovers has ever done before, is collect rock samples. And we’re working on plans to bring those rock samples back. So there’s a drill out on the end of the robotic arm, and that drill, we’ll be able to put tubes in it. Sample tubes inside the drill bit, and as the drill goes into the rock, it’s going to actually capture those rock cores into these tubes that we’re going to cap and seal up and store for later to bring them back home.

Jim Green: So those tubes of metal that contain this rock core, there are a couple of inches long, it’s sort of like a piece of chalk, or today, based on kids not understanding what chalk is, sort of the big Crayola-crayon-sized objects. So what are we going to do with those and how are we going to get them back?

Mitch Schulte: Well, what we’re going to do with them is first collect them, and we’re going to very carefully choose which samples we want to sample or which rock we want to sample. Once we have those, we’re working on plans to send another set of missions to Mars, to go retrieve the samples and bring them back. So we’re working with our international partners to provide all of the hardware that we’re going to need to land a rocket on Mars, have a rover that will go collect the samples that Perseverance is going to collect, bring them to the rocket and launch it off of a platform off the surface of Mars. Once they’re in orbit around Mars, they’re going to be captured by an orbiter and the orbiter, then we’ll leave Mars orbit and return those samples to Earth.

Jim Green: Wow, that sounds complicated. But I guess that’s the easiest way that we can get it. But this fetch rover that’s going to go and collect the samples, where’s it going to find the samples? Does it have to run down Perseverance and get them from Perseverance?

Mitch Schulte: Well, we have a couple of different options for that and we’re still working a little bit on the plans for how we’re going to do this operationally. One idea is that Perseverance can actually keep the samples on board and help deliver those samples to the Mars Ascent Vehicle or the rocket that’s going to bring them back. The other idea is that we could leave the samples on the ground on Mars, in particular designated locations that the fetch rover can go and retrieve those samples and bring them to the Ascent Vehicle.

Jim Green Well, what are some of the other instruments on the rover?

Mitch Schulte: Well, we have instruments designed to really look at different scales of materials on Mars. So before, we’ve really been investigating things at really large scale from orbit. And even with the rovers, you look at things, the rovers that we’ve sent so far, you look at things on a fairly large scale. So for example, Curiosity when it analyzes samples on Mars, takes rocks and powders them up. And so you lose all of the information about textures and locations of particular features inside the rock.

Mitch Schulte: So the instruments on Perseverance were really selected in order to get down onto the scale that microbes live at. And so we really want to look at those scales and textures to see where the water was flowing, and to measure the chemistry and look for organic material on that kind of scale.

Jim Green: Yeah, so those are higher resolution imaging systems. But we also have some other things like a weather station, what is that going to measure?

Mitch Schulte: So the weather station is really impressive. It’s being provided by Spain. And it’s going to include all the kinds of weather measurements that you see here, that we take on Earth. So it’s going to measure the temperature of the air and of the ground, it’s going to measure the relative humidity, it’s going to measure the pressure of the atmosphere. It’s also going to measure the ultraviolet radiation that’s reaching the surface of the rover. And finally, it’s going to be looking at the dust particles that are falling on top of the surface of the rover because as you know, the dust is a really interesting and key feature of the weather and the atmosphere of Mars and really understanding what that dust is like, is really going to help us out when humans eventually go to Mars.

Jim Green: Well, another instrument is a radar. What are we using the radar for that’s tucked underneath the rover?

Mitch Schulte: Yeah, so it’s called a ground penetrating radar or GPR. And this radar is designed to look at subsurface structures. So we use this on Earth all the time to look for what I like to refer to as buried treasure. So you can see ancient cities, you can see ancient riverbeds, you can see all kinds of different things, large storage tanks that have been abandoned in the past, really interesting if we’re looking in environmental kinds of issues. But the real key to ground penetrating radar is being able to see the subsurface structures of the rocks themselves so that we can identify features that might not we might not see at the surface so easily, we also might be able to detect the presence of any ice, deep under the surface of Mars.

Jim Green: So that’s a really neat concept. That tells us perhaps how the water deposited material onto the crater floor over time. Well, in that concept, how deep does the radar go?

Mitch Schulte: So the radar generally looks between about 50 and 100 meters deep.

Jim Green: Wow.

Jim Green: So there’s another instrument that really piques my interest on Perseverance. And that relates to human exploration. What’s that instrument?

Mitch Schulte: So that’s an instrument called MOXIE. And it’s intended to be a technology demonstration. So for when we eventually send humans to Mars, we’re really going to want to be able to rely on some of the resources that Mars has. One of those resources is carbon dioxide. So the atmosphere of Mars is made primarily out of carbon dioxide, even though it’s very thin, it’s about 95% carbon dioxide. So MOXIE is going to take atmospheric gas, so it’s going to take carbon dioxide out of the atmosphere of Mars, and electrochemically extract oxygen out of it. And of course, oxygen has a number of uses for humans, including air that we can breathe, but what we’re really designing this for is to be able to create what we call propellant grade oxygen, so that we can use it as rocket fuel.

Jim Green: Interesting. Well, that will be an exciting instrument. Now, you mentioned the dust. There’s dust in the air in Mars, all over the place. And we always worried about that with Spirit and Opportunity because they were using solar power from solar panels. Is that going to be a problem with Perseverance?

Mitch Schulte: That’s not going to be a problem with Perseverance, because Perseverance is bringing its own power supply. It’s going to be nuclear powered.

Jim Green: Wow. Okay. Well, once we core the rock and pull it out, and then put it in these tubes, do we have instruments that can look into the holes and interrogate what the rock record is inside them?

Mitch Schulte: So we have a couple of have different instruments that will be able to do that. Obviously, we have cameras and so we can take pictures with the cameras mounted on the mast or out on the end of the arm. But we’ll also have two instruments that use lasers to help do their measurements. One of them is called SuperCam, and this will be able to shoot a laser from the mast into the hole and be able to determine a number of things, including the chemistry of what we’re seeing inside the hole and looking for organic material in there. It’ll also be able to look at some mineralogy with its visible and near infrared spectrometer. Another instrument that we have that uses a laser is called SHERLOC and it has an ultraviolet laser that will be able to look into the hole to detect organic compounds and certain types of minerals that we think form in liquid water.

Jim Green: So these lasers are so intense, they actually evaporate the rock and you get a spectrum?

Mitch Schulte: So that’s true for SuperCam and in fact-

Jim Green: It’s true for SuperCam.

Mitch Schulte: Yeah. And so the technique is called laser-induced breakdown spectroscopy or LIBS. And what it does, is fires a very intense beam of laser light at a surface, that causes it to vaporize and turn into a plasma. Now that plasma emits different wavelengths of light, depending on what chemicals are in that sample. And so the SuperCam instrument can then detect those chemicals.

Jim Green: That sounds great. Well, we’re going to bring the samples back, hopefully by the end of the 2020s, somewhere around there. And what’s going to happen to them once they get here on Earth?

Mitch Schulte: Well, we’re still working on that as well. So first, we need to figure out a place where we’re going to keep the samples because unlike other missions that have brought samples back from celestial objects before, like comets and asteroids, this time, we’re bringing samples back from a planetary body, Mars, that may have had life on it. So we have to be careful about what we call planetary protection. So we want to make sure that the samples are safe, before we allow scientists all over the world to look at them.

Mitch Schulte: So we’ll have to have a facility to receive them. Once we have that facility and figure out what to do with them, what we’ll probably do is open it up to the scientific community once we’ve determined that they’re safe. And so that scientists from all over the world can apply to obtain samples and study them.

Jim Green: This is not a new idea. You can think back, at least I can, because I was a teenager during the Apollos, but indeed, when those astronauts came back from the moon, they went into quarantine and they were there for several days. And the samples they brought back went into quarantine. What were they looking for?

Mitch Schulte: Well, so one of the ideas, especially for Mars, is that life might have existed on Mars in its past and might even exist there today. Back before we had the samples from Apollo, we thought the same kind of thing about the Moon. So we weren’t sure what we would find, we weren’t sure if there were any bacteria or viruses or anything like that in those samples that they brought back from someplace we hadn’t been before. So they were just trying to be careful about making sure that we didn’t contaminate Earth with anything.

Jim Green: Yeah, so what happened is they eventually let them out of the trailer.

Mitch Schulte: That’s right.

Jim Green: They were allowed to go home because the Moon, didn’t look like it was going to support any life. So that also enabled them to open up the samples. So this is going to be an exciting time for the sample scientists to really study this material for decades.

Jim Green: Well, we’re sending Perseverance to Mars right now, how does this relate to our overall Artemis program?

Mitch Schulte: So the goal of the Artemis program, of course, is to get humans back into deep space. First to the Moon and then hopefully, eventually to Mars. We in the Mars Exploration Program like to point out that we’ve been sending things to Mars for quite some time. And we’ll be happy when the humans finally get there. But we’ve got an entire planet inhabited by robots at the moment. And so what we’re doing in sending all of this technology and these technology demonstrations and this hardware to Mars, is really helping us move forward in the technologies that will enable humans to visit Mars.

Jim Green: So the Artemis program will land humans on the Moon where they’ll learn to live and work on a planetary surface. And Mars is such a different place. We just got to know everything about it before we send humans there. And that’s what we’re doing with Perseverance.

Jim Green:Perseverance is going to be taking with it a helicopter. We just announced its new name. It’s called Ingenuity.

Mitch Schulte: Well, Jim, we’re actually going to fly a helicopter on Mars for the very first time, and it’s–

Jim Green: Wow.

Mitch Schulte:… going to ride along with Perseverance.

Jim Green: So how does that get deployed? Once the rover lands on Mars, what happens next?

Mitch Schulte: Yeah. So we’ve built a little house for the helicopter on the underside of the rover. And so after the rover lands, it’s going to get lowered down to the ground. It’s folded up inside this house. It’s going to get lowered down to the ground on cables. The cables are going to get detached from the rover, the rover will drive away and then the helicopter will unfold itself and be ready to fly.

Jim Green: So it’s a copter with two major wings, right, that are crossed like a big X?

Mitch Schulte: That’s right. Yeah, so it has two large blades. They’re each about a meter long. The helicopter itself only weighs about 1.8 kilograms, though. So it’s fairly light. And most of the mass is actually because of the battery that’s going to power the blades. And so we have two blades that sort of cross each other, as you’ve pointed out, and the reason for that is they’re going to spin in opposite directions.

Jim Green: Wow.

Mitch Schulte: So it’ll stabilize the helicopter when it’s flying.

Jim Green: So it doesn’t have this tail prop, so to speak?

Mitch Schulte: Yeah, if you’ve seen helicopters flying here on Earth, they have the big rotor at the top, but they also have to have a blade that spins on the back of the tail. And that’s to keep the helicopter from spinning around as the torque of the blade spinning on top makes it want to spin in one direction. So by having two blades that spin in opposite directions, we won’t have that problem.

Jim Green: All right. So we’re going to send it a command, “Take off.” And so it’s going to go up and how high does it go? And what is it supposed to do?

Mitch Schulte: So we what we’ve planned for it is not necessarily how high it’s going to go, we can see what it does. But what we’re really interested in is making sure that we can operate the helicopter for certain periods of time. So at the moment, we have five demonstration flights planned, each one a little bit longer than the last one. And so we’re going to first, make sure that it actually lifts up off the ground and can actually fly. And then we’ll test and see how long we can do that. And then if we get creative, we can start to maybe maneuver it around a little bit.

Jim Green: So I’m sure during those early tests, we’ll be able to, from the imaging from the Perseverance rover, look at the helicopter raise up and get an idea what it’s doing.

Mitch Schulte: Yeah, that’s right. So we have lots of cameras on Perseverance. So we’ll be able to take all kinds of great pictures and probably some video of the helicopter doing its thing. We’ll also have a video camera on the helicopter itself, so it will be taking—

Jim Green: Wow.

Mitch Schulte:… video as it’s flying.

Jim Green: Okay. So how many days does it take to really test the helicopter out?

Mitch Schulte: Well, so we’re going to want to make sure we check everything out. After we do the first test flight, assuming that goes well, then I don’t think it’ll take us very long to get the rest of those flights done. If things do go well, then we are thinking maybe we could do a couple of extra test flights. But this is intended to be a technology demonstration.

Jim Green: Right, right.

Mitch Schulte: So we have some serious science to do with Perseverance. So we’ll want to get to that pretty fast, too.

Jim Green: But this opens up a whole new idea — a whole new series of things one can think about doing. So if the helicopter works well, what are the kinds of things that we anticipate we could use aerial flights on Mars in the future for?

Mitch Schulte: So you could imagine all kinds of things. One would be a very obvious thing, which would be a scout. So you could fly the helicopter over a hilltop that you might not want to send the rover to, to check out the terrain and make sure it’s safe for the rover to go operate over there. If you’ve ever been in an airplane and looked at the ground below you, you see very different scales of geology, from different elevations as well. So walking, hiking the trail is one thing, being in an airplane is a little bit different. Being in a jetliner flying high above it, you see very different scales of geologic features. So you could do some interesting geologic work with the helicopter.

Mitch Schulte: And then finally, of course, just as a transportation mechanism, again, to get things moved around relatively quickly. You could imagine, not that we were planning to do this, but you could imagine having a helicopter to go pick up samples and bring them to a particular place.

Jim Green: Well, I have another one I’d like to do, and that is have a helicopter land in a major crater where we see what may be water actually leaking out of aquifers and running down the sides of the crater during the summertime and fly up and look into these craters. Look into these potential aquifers.

Mitch Schulte: That’s a great idea, Jim. And again, places where you wouldn’t want to send a rover or can’t send a rover, if it’s on the side of a cliff where there may be active water coming out then, the helicopter would be a great idea for that.

Jim Green: Yeah, wow. Okay, this is a really exciting mission and I’m so delighted that we’re doing some technology demonstrations along with it. Fantastic.

Jim Green: Well, Mitch, I always like to ask my guests to tell me, what was that event or person, place or thing that got them so excited about being a scientist. That propelled them to become the scientists they are today. I call that a gravity assist. So, Mitch, what was your gravity assist?

Mitch Schulte: Well, I’ll give you two. I’ll give you an event and a person.

Mitch Schulte: So, like you, I’m old enough to remember the Apollo missions. And I was 3 when Neil Armstrong first set foot on the Moon so-

Jim Green: Wow.

Mitch Schulte:… a little too young to remember that exact event. I know I was watching it because my parents told me I was. But I sort of grew up then, with people walking on the Moon as they were sending people, all the way up through Apollo 17. I was watching that on TV and thinking, “What a great place to go, the Moon would be.” So that was one of the reasons I got interested in doing science. At the time, of course, I grew up in St. Louis, which is where McDonnell-Douglas at the time, had its headquarters. And they are the ones who built the Mercury capsules and did a lot of work on the space program. So it was all around me and it was a natural thing to do.

Mitch Schulte: The person that most inspired me, I would have to say, was one of my earliest geology professors at Washington University, Lynn Walter, who’s now at University of Michigan. I took historical geology class from her and she was just the most caring, creative professor that I ever had. And she’s the reason I stuck it out and became a geologist.

Jim Green: Wow. Okay, that sounds exciting. We all have our different paths. Mitch, thanks so much for a really exciting preview of Perseverance and its landing on Mars.

Mitch Schulte: Well, thanks, Jim. It was great to be here. And everyone should pay attention for the launch on July 17, and landing seven months later on, February 18, 2021.

Jim Green: Well, join me next time as we continue our journey to look for life beyond Earth. I’m Jim Green, and this is your Gravity Assist.


Lead producer: Elizabeth Landau

Audio engineer: Emanuel Cooper