Planetary Radio: Space Exploration, Astronomy and Science - Rob Manning and Landing on Mars

Episode Date: April 14, 2015

Landing on Mars is hard, and the bigger you are, the harder it gets. Rob Manning returns to tell us about one of NASA’s best hopes for getting much bigger spacecraft down there—spacecraft that may one day carry humans.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Flying saucers are headed to Mars this week on Planetary Radio. Welcome to the travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. Yes, more of the Red Planet this week. How'd you like that inflammatory opening line? It's almost accurate, as we'll hear from Rob Manning. Rob returns to tell us about the system that may help us get much bigger spacecraft down to the surface of Mars, spacecraft that may someday carry humans. Bill Nye is also all about Fourth Rock, as he mentions more innovation from SpaceX. Bruce Betts and I will take a virtual trip down under for this week's What's Up.

We begin as we should with Emily Lakdawalla. Emily, welcome back. You have a question for me. That's a switch. Yeah, Matt. So my question is, and I'm here, I'm taking on the role of Bruce Betts' random space facts, which is the moon in the solar system with the densest atmosphere? Oh, well, everybody knows that. It's Titan, that smoggy moon out at Saturn. Where's my t-shirt? All right, well, that was a softball just to warm you up. Now, what's the second densest? Okay, now I know a lot of moons have something like an atmosphere. I mean, even our own moon, I know they've detected gases, but I don't know. I bet you've written about this, though. I have indeed. Some space

fans may know that there is another moon that has an atmosphere that we've seen geysers into and being blown away. And that one is Triton, a moon of Neptune. It's not nearly as thick as Titan's, but it is an atmosphere. There is wind there. But I think even the biggest space fans would have a really hard time guessing what the next couple were. There are, in fact, two more moons that have atmospheres that are dense enough for their molecules to collide with each other and create wind and weather and climate. The first one of those is Io, whose atmosphere is partially supported by its volcanoes spewing stuff out into space, but is more supported by sulfur dioxide frost turned into gas during the day. turned into gas during the day. And then there is a newly discovered fourth moon atmosphere out there. And it's got to be the most unlikely body I could ever have imagined. It's Callisto. Oh, and this is the one that you've only just learned about, right?

Yeah, that's right. So Callisto is the outermost large moon of Jupiter. It's generally regarded as one of the deadest moons in the solar system. It's got this really ancient surface. And as it turns out, it also has a very, very thin, but still possibly windy atmosphere made of oxygen gas. This must have come as a surprise to a lot of people. How did you find out about it? Well, this is something that I'm kind of proud of. You know, most people find out their space news by reading press releases where institutions write up stories and then everybody else writes an article about those stories. But I find stories a lot of the time just by reading tables of contents of professional journals. It's out there in the public for everybody to see. And I saw this title that said, An Atmospheric Callisto.

And I said, Callisto? I downloaded the paper and I read it. And by gosh, they reported the discovery of an atmosphere of Callisto. I downloaded the paper and I read it and by gosh, they reported the discovery of an atmosphere of Callisto. And I'm the only one who wrote about it because I'm the only one who was reading that table of contents, evidently. I bet now that you've written about it, and it is in full disclosure, it is in an April 8th blog entry at planetary.org, which I actually did read. Now that Emily's put it out there, I bet it's showing up other places as well. That does

seem to be the way things work. There is much more here. If you are curious about atmospheres on moons, this is the place to go this week. I hope that you're going to add some mention later of Endor, Pandora, the other moons with atmospheres that are waiting out there for us to discover, Emily. I'll let you do that, Matt. Okay, I'll do my best. Thanks so much. Thanks, Matt. She is, of course, our senior editor, planetary evangelist for the Planetary Society, and a contributing editor to Sky and Telescope magazine, Emily Lakdawalla. Let's check in with Bill Nye.

Bill, a week has passed since our long conversation about the humans orbiting Mars workshop. It seems, though, that we aren't the only ones talking about going to Mars. That's right. The NASA Advisory Council had a big meeting, and they talked about putting off decisions. But the big thing that they did talk about was getting life support systems on the International Space Station that could go for three years. The International Space Station is resupplied quite often. By often, I mean big rockets take stuff up there.

But if you're on your way to and from Mars, there's no, you can't do that. There's no resupply. So this is a very important thing that Bill Gerstenmaier talked about at this NASA Advisory Council. And I'm glad it's on the way. So no matter what people decide to do,

have an orbital mission, as the Planetary Society investigated, let's call it investigated, that looks quite possible. Or you really go for the big prize and try to land on Mars. Or you abandon the whole thing. You still want to have this ability to live in space, if I may, indefinitely on self-supporting life support. That's a big thing. So at least they're talking about it. And meanwhile, Elon Musk and SpaceX, their goal, their big goal is to go to Mars. And they're going to try again. And the big thing is to lower the cost of getting into space. That's SpaceX's mission or one of their big objectives. I love Elon's statement that he will not sell public shares in SpaceX until his regular shuttle

service is running to Mars. That's probably a ways off. That's something to keep in mind. Yes, right. You can buy shares in Tesla, though, if you want to invest in his big ideas. Yes. Along this line, lowering the cost to low Earth orbit is a step into getting to Mars, in his view, which I think is pretty reasonable. And they're going to try again to land their booster on a barge. It's the coolest idea. In other words, they want to reuse the first stage of the rocket by having it gently land on a barge out in the ocean downrange from Cape Canaveral. It's very cool. Now, when people hear this, they will know whether Elon and company have been successful at that or not. As we speak, it's still up in the air, maybe literally.

Unintended, yes. So it's a very exciting time. All these people are really talking about really mounting a mission to Mars and really making the necessary steps. Life support, lowering the cost to orbit. These are big ideas. at the Space Symposium in Colorado Springs, which is always, Matt, to me is just amazing. There's all these Air Force people, all these industry people, people that make huge rockets, walking around, talking about space exploration and doing deals. It's really exciting. It's good to be part of the conversation. I'm sorry you won't be part of the conversation at the Planetary Defense Conference,

where I will be in Rome, but good to know that there'll be another Planetary Society contingent at Space Symposium. Have a great time there. Yeah, and you have a great time in Italy, and enjoy the food and the coffee. Carry on. Grazie. Ciao. Ciao. That's Bill Nye. He's the CEO of the Planetary Society, who joins us most weeks here on the radio show. Back in a minute to talk about getting down to Mars with the guy who is the world's greatest expert on that topic. It's always exciting to see what is happening in the high bay at the Jet Propulsion Lab. The mammoth clean room has been the birthplace for scores of history-making robotic spacecraft. When I entered the observation level a few days ago, a huge disk was starting to spin below me. When I entered the observation level a few days ago, a huge disk was starting to spin below me. Bunny-suited engineers watched as the 6-meter-wide SIAD-R began this test. SIAD, that's the Supersonic Inflatable Aerodynamic Decelerator. Someday, something like a SIAD, along with an equally innovative supersonic parachute and rocket engines,

may allow men and women to walk on Mars. Much work remains before that day comes. One of the leaders of this work stood with me above the high bay. Rob Manning has joined us several times, always to talk about how to land machines safely on the Red Planet. Rob is now chief engineer for the low-density supersonic decelerator system that includes two versions of SIADS. Minutes later, we sat down in a nearby conference room. Rob, it is great to get you back on Planetary Radio.

Thank you, Matt. It's great to be back with you. Years ago, we sat across a table like this, and you told me, we have hit the ceiling of what current technology can do to get us down to the surface of Mars. Airbags, sky cranes, it all worked great. Thank you. But you said, we're not sure what we're going to do next. That's true.

Has that been solved? Well, we are in the process of solving it. I think what's really exciting is that the realization of this limitation, I mean, not just for, I mean, think about this. I'm talking about limitation for robotics. We have a rover on Mars, Curiosity rover, about 900 kilograms, what we call a little under a metric ton, 1,000 kilograms. In our vision, we'd like to not just send something bigger than a rover. For example, a vehicle that would have a rocket on top that would

take samples from Mars and to put it into Mars orbit. We'd love to do that. We think that's going to weigh a lot more in Curiosity. But our entry-descent landing system is a bit limited. The technology we've been using now for the last 20, 30, 40 years has all been based on the Viking engineering work that was done in the late 1960s and early 1970s. And that has been wonderful. We've been capitalizing on those tests and developments for all these years. In fact, most people don't really realize that the only place that large supersonic parachutes

have been used in the last 20 years is on Mars. We don't need them here. We live in this big, thick soup of an atmosphere. So, yeah. So I'm saying, hey, we're of an atmosphere. Yeah. So, yeah. So I'm saying, hey, we're having a hard time getting rovers, bigger rovers, bigger vehicles on Mars. We need them. But don't we want to land people there someday?

There has been some talk about that of late. Yeah, I've heard that. Yeah. So I thought maybe that problem should be solved too. Now, I'm not saying that the technology that we're using and testing today are directly going to be used for human landings, but we have to push this envelope and figure out how to get larger masses to the surface of Mars. So what we're aiming for with this mission is something at least to double the capability of the interdescent landing system that Curiosity used to land on Mars. And we're doing that with two new aerodynamic decelerator tricks that we pulled out of our sleeves here.

One trick is an inflatable donut that inflates around the perimeter of the space capsule. So this vehicle, remember now, we come in at very high speeds, 13,000 miles an hour to the top of the Mars atmosphere, and we use a heat shield going very fast to slow us down. The heat shield protects us against the incredible forces and heat of that atmosphere as the vehicle is beginning. Even that thin atmosphere. Well, yeah, when you're moving that fast, the energy transfer goes as the square velocity. And so the velocity is already so high.

When you multiply time itself, it gets to a really big number. So not that different, really, than entering on Earth way up high. So even though it's very thin collectively, Mars' atmosphere is a bit like Earth's atmosphere if you were to land 120,000 feet above the ground on Earth. And so the atmosphere above that is very Mars-like, very similar. So one trick is this doughnut. The second trick is a larger supersonic parachute. Now, the parachute that we used to land Curiosity rover was about 21 meters in diameter.

That's about the size of the largest supersonic parachute ever tested on this planet back in the early 1970s. And that was these very expensive tests. Now, how do you test these parachutes, larger parachutes in this new inflatable donut called the Supersonic Aerodynamic Inflatable Decelerator, or SIAD for short? How do you test these on Earth? Well, the place to do it is to do your entry process way up high above Earth's atmosphere, and you try to slow down way above 120,000 feet. And that's exactly what we're doing this summer. And also did last summer when this system was tested in the skies over Hawaii, right? Yes.

Which partly worked great, but it's both elements of this system that you just described, right? Because a lot of attention is given to the donuts that you described, also known as the flying saucers. Yeah. But the parachute seems to be just as important a component. Well, in fact, they kind of go together. So imagine you're trying to land the space shuttle at 120,000 feet. Now, when the space shuttle is entering Earth at 120,000 feet, it's going very fast. It's going several times the speed of sound, maybe four, five, six times the speed of sound.

That's at the point where you're supposed to be at zero miles per hour on the surface of Mars. So the whole trick of landing is making sure you come to a stop before you hit the ground. That's the whole trick. It's always good. Yeah, that's the key. And the problem with the Mars atmosphere is it's so thin down low. I mean, it's fine for entering, but the trouble is your job's not over with. After your heat shield has done its job, now what we did on Curiosity rover and previous missions all the way back to the Viking missions in the 1970s was inflate a supersonic parachute.

And we do that about two times the speed of sound. Now, Mars' speed of sound is a little bit slower than Earth's, but it's about comparable. So we slow down with a parachute to about 200 miles an hour. Okay, now this is with a full-size parachute. You're falling with a parachute on Mars as fast as a skydiver on this planet flies without a parachute. So even though the parachute's very handy, even that doesn't complete the job.

Unlike something like the Apollo missions that landed directly on parachutes right on the ocean, or the Soyuz, which uses parachutes within a meter of the ground where they fire little tiny rockets to cushion at the end. But still, we have all this kind of Rube Goldberg series of steps needed to slow our vehicles down. Entry, heat shield, supersonic parachute, and then rockets at the end to lower us, slow us down very much like you do land on the moon with rockets firing backwards.

The trouble is with a bigger parachute, a larger vehicle, I should say, you're still going so fast, you've got to slow down enough so you can open the supersonic parachute. The supersonic parachute doesn't want to open much above two times the speed of sound because above that, it starts to melt. above two times the speed of sound because above that it starts to melt. Really, about Mach 2.5 to Mach 3, your actual fabric is actually starting to melt. So we need to slow down to the speed where we can open the parachute. To do that, we put this inflatable donut, and we open that about 10, 15, 20 seconds earlier than the parachute. So what that does is takes the vehicle from about four times the speed of sound,

four or five times the speed of sound, down to about Mach 2. Those are pretty good brakes in a little short period like that. Yes, they are. The whole idea is increasing the amount of drag area of your vehicle, the amount of stuff. We really want this vehicle to look like a giant billboard to slow it down, just to sort of to stop its motion through the air. And that's all these tricks are, is to take advantage of that.

Now, would you do all this for a human scale mission? Probably not. That's a lot of stuff that has to work. And the trouble with Mars, humans missions, the larger the scale of vehicle, the heavier it gets because the mass goes with the total volume of the vehicle. But the area only goes as a square as the length of the vehicle rather than as the cube. So what happens is as the vehicle gets bigger and bigger and bigger, this problem gets worse and worse and worse. So we need to even break the mold. And what we're ultimately going to do, I think, not that parachutes and science wouldn't be part of the ultimate equation, but very, very likely it will rely on another technology, a technology that SpaceX, for example, has been using lately, which is supersonic retropropulsion, we call it SRP,

flying your rockets backward faster than the speed of sound and having a special rocket configuration so that allows you to do that stably. Trouble with that is it takes a lot of fuel. The fuel weighs a lot more than a parachute. And so that means you have to carry more. That means you need bigger rockets on Earth to push this vehicle up so we can get a boost from Earth to Mars. So this has been kind of the challenge we've got is how to do all this stuff without requiring rockets that are far bigger than anything we can imagine.

That's Rob Manning. He'll tell us more about landing on Mars after the break. This is Planetary Radio. Hey, hey, Bill Nye here. I'd like to introduce you to Merck Boyan. Hello. He's been making all those fabulous videos, which hundreds of thousands of you have been watching. That's right. We're going to put all the videos in one place, Merck. Is that right? Planetary TV.

So I can watch them on my television? No. So wait a minute, Planetary TV is not on TV? That's the best thing about it, they're all going to be online, you can watch them anytime you want. Where do I watch Planetary TV then, Merc? Well you can watch it all at planetary.org.tv. Random Space Fact!

Nothing new about that for you, Planetary Radio fans, right? Wrong! Random Space Fact is now a video series, too. And it's brilliant, isn't it, Matt? I hate to say it, folks, but it really is. And hilarious. See? Matt would never lie to you, would he? I really wouldn't. A new Random Space Fact video is released each Friday at youtube.com slash planetarysociety. You can subscribe to join our growing community and you'll never miss a fact.

Can I go back to my radio now? Welcome back to Planetary Radio. I'm Matt Kaplan. It's such fun to talk with Rob Manning of JPL, partly because his enthusiasm is so infectious, but also because he's always working on something wild and wonderful. Now he's chief engineer for development of NASA's low-density supersonic decelerator, or LDSD. This two-part system for landing much bigger spacecraft on Mars will get another critical test high above the islands of Hawaii this summer.

It's basically a repeat of last summer's test. It's hard. It's complicated to get down to the surface of Mars. It is. And the tests that are underway, I started to talk about the one that took place last summer, where a lot worked really well. Yes, it did. It was great. But the parachute, when it came out, it immediately started to tear.

And it was in shreds before long. In fact, to our surprise, the parachute started to tear almost as soon as it came out of its bag. And you can see that in the video. We'll put up a link to this test. It is a spectacular video. Yes, thank you. Well, nothing like high-resolution and high-speed video to really help. In fact, the video that we have from this flight is far better than any other videos, any prior supersonic inflation.

So we bring all the parachute experts together in a room. We're all staring at these. These are people who remember the details of the tests in the 1960s and 1970s. And they look at this and are like, oh, this is interesting. This is – oh, this couldn't possibly have happened on our previous mission. I mean they looked – their previous parachutes didn't break, by the way. There was at least – there least one where there was something that might be something similar to what we had. But our failures seemed to be right out of the bag, really out of the gate, as it were. So we said, what is going on?

And we're looking at the complicated dynamics of how the flow works. The interesting thing that happens with supersonic speeds is it's really not the speed so much. Well, it is the speed, but it's also the fact that air is very thin. It's moving very fast, but it's really not the speed so much. Well, it is the speed, but it's also the fact that air is very thin. It's moving very fast, but it's very thin. When you open a parachute in our thick part of our atmosphere where we like to live, the parachute doesn't open instantaneously fast. It has to fight the whole, has to move through the soup of an atmosphere. Up at 180,000 feet, the parachute opens up so fast that it gets this whipping action. And so we need to make sure that our parachute's designed for that.

So what we did, so last year's test really was not so much about testing the parachute. We threw the parachute in there. We wanted to get a test out of it out there too. But this really was a shakeout test for this whole test infrastructure. Lifting the vehicle up on a balloon. No one's ever lifted a test vehicle with a big Star 48 rocket before. Flying it out over the Pacific, aiming it properly, dropping it, spinning it up, firing the solid rockets, getting the right altitude, and then inflating the donut, and then pulling this parachute out

of the can, which itself required some tricks that we pulled out, which are not typical of Mars missions, where we had to actually use an inflatable balut, which is this kind of combination parachute and balloon that we throw out the back with a big mortar cannon. And that inflates, and that then itself, talk about Rube Goldberg, right? Pulling out this big 200-pound parachute, which allowed it to finally inflate. So this time, we're doing almost exactly the same test.

The difference is we have a different parachute. We looked carefully at what was going on with the dynamics and the physics that was going on, and we said, really, it needs to be stronger. That's kind of obvious. But we wanted to know how much stronger. And that turns out to be a very difficult question to answer. But we could put bounds on how much stronger it needed to be. And that's what we did.

And so we built, instead of a parachute, there was a combination of what's called a ringsail parachute, which has rings all the way from the skirt all the way up toward the center. These are concentric pieces of fabric and structure with air gaps in between them to give it stability. Last summer, we didn't fly that. We flew a parachute that looked a little bit more like the parachutes that we've flown traditionally. We call it a disc gap band parachute, which is a big piece of fabric, which is the canopy with a hole in the middle. And outside the ring of the canopy, there's a gap in the suspension lines. And then a band of really a fabric in the shape of a big

cylinder goes around the parachute. And that's the parachutes, the designs we've been flying for all these years since the 1960s, because that's what was tested in the 1960s. What we tested last summer was a kind of a hybrid between the big disc and a ring sail parachute. And so this time we said, no, let's go all up. Let's not have big sheets of fabric. Let's put the rings all the way up to the back, make it actually part of a hemisphere. It's not just a combination of a flat fabric, but actually cut the fabric in the shape of a hemisphere. And it makes sure that it has the right fullness so as it inflates, it doesn't put too many forces on the actual Kevlar structure. These parachutes have not just the suspension lines that go all the way up to the top, but they also have concentric rings of cordage of Kevlar to hold it together.

So that's really – we've been learning far more than we ever thought we wanted to know about fabric and sewing. But there's some very subtle things you can do. Well, the good news is we tested this parachute. There were two different – slightly different designs that we tested using our rocket sled up at NASA, at the Navy's China Lake Weapons Center. Okay, let me stop you there because I was going to bring that up. For an old space geek like me to see rocket sleds in use the way they used to put humans on them because we didn't know what would happen, it was just really cool. It is cool. And the folks up at China Lake, the Navy's China Lake Weapons Center up in Ridgecrest, California, up in kind of the high desert, they have done amazing things in helping us.

They're very creative people. They are able to conjure up these structures and facilities and how to use their many-mile-long rocket sled and old rockets. Some of these rockets, by the way, go back to – were built in the 1960s. Oh, no kidding. And we're taking rockets that have been in storage for decades, putting them on the back, and they light up. These solid rockets light up first time. And there are wonderful ways of pulling parachutes. So you might say, what does a rocket and a parachute have to do with each other? Well, in this case, if we could, we would like to take our large parachute into a wind tunnel.

our large parachute into a wind tunnel. For our previous parachutes, for Spirit and Opportunity rovers, MER, and Curiosity, we use the world's largest wind tunnel called the Infact. It's up at the NASA Ames facility. It's a huge wind tunnel, 80 by 100 feet. It's a big thing. But this thing, it's still too small to test the parachutes we're looking at flying that are almost 100 feet across, right? So we need to figure out a different kind of wind tunnel. So we said, well, ultimately, what we'd like to do is like to pull a parachute through the air when it's fully inflated state to see how strong it is when it's fully inflated. So we imagine this, you know, a truck or a train pulling this parachute, but the parachute would drag on the ground. So we said, what if we just pull the parachute up in the sky and build ourself a giant pulley

and pull a rope through the pulley and pull the rocket sleds horizontally while you pull the parachute straight down? You've just explained what I, when I watched that sled test, what I said to myself, what the heck is going on here? There was a pulley. It's a giant pulley. The pulley itself is about a one-ton piece of steel, and it's attached to a structure embedded in a million pounds of concrete that we had to dig and pour in the desert on either side of the rocket sled. It's supported there right above the rocket sled

very tightly, so it can handle a quarter million or even an eighth of a million pounds of rocket sled force to pull this parachute straight down. And that's exactly what we did. So the trick is we pull the parachute up with a helicopter, the helicopter dropped the parachute, the parachute inflated, then the test begins where we actually fire the rockets and pull the parachute straight down with as much force as we expect the test vehicle or Mars mission to do, plus a lot more because we wanted to just see how strong it was. And we did those tests twice just in the last month. And so now this summer we'll see essentially a repeat of last year's test but with this upgraded parachute. Yes. Any changes to the SIADs, the donuts?

The SIAD's going to be the same. It went perfectly last time. We said, we're just going to do it again. We did change the test vehicle. We added new cameras. We changed the configuration. One of the things I wanted to do is be able to look at the shape of the parachute as it's inflating.

So we put stereo cameras on. We actually use GoPro cameras that will look from different angles across the vehicle. And from that, we hope to be able to deduce something about its shape from the stereo. You're talking about off-the-shelf GoPro cameras? Yes. They ought to be giving you guys something for that. Oh, yes, I can't remember about that. They've been very good at helping us.

We work with other camera vendors, too. They're not the only ones. For the machine vision, the high-quality, high-resolution, and high-speed cameras are also amazing pieces of equipment that really help us. You've got two models of these SIADs, a 6-meter and an 8-meter. But there are other things that set the two apart. Yeah. Now, we haven't tried testing the bigger one. The bigger SIAD is quite different. This other donut is very much like the bouncing airbags that we built for Pathfinder Spirit and Opportunity.

Basically, they're sewn Vectran membrane with a gas generator inside to keep the pressure up. In this case, what inflates them is our gas generators, multiple. And this is the six meter that you tested before and you will again? Correct. The other one also has a gas trainer just to get it started, but it's so much larger that gas trainers can't really keep up. So what this thing has is actually intake scoops that stick out into the breeze, and we let the ram air keep the structure inflated. And so, ironically, the air itself keeps the structure, which then slows the vehicle down. Fascinating. Absolutely fascinating.

This is going to let us get not just heavier stuff to Mars, but I've read that it will also maybe allow us to explore stuff at higher altitudes that we haven't been able to reach. Yeah, that's true. And because of this atmosphere being so thin at Mars, we've been forced to land so far, basically below sea level. We define zero elevation as kind of the average altitude on Mars. So Mars, kind of like Earth, most people don't know that Earth, there is something called

a hypsometric curve, which tells you what fraction of our land is at what elevation. Turns out Earth has these continents that stick up with mountains on them that produces a lot of high-altitude stuff and a lot of stuff at sea level, of course. But there's another big fraction of Earth. In fact, a far larger fraction of the Earth is down well below sea level at the bottom of the ocean. So there's really two sets of altitudes, below sea level and above sea level, and not much in between on this planet.

And Mars is very similar. The northern half of Mars, the lowlands of Mars, are very, very low, almost like ocean bottoms. And then the southern highlands of Mars stick up very, very high. So our missions have been so far, we've been kind of forced to land at the margin between the highlands and the lowlands. The highlands have really become off limits because there just isn't enough air there. So one way to slow down to get there is to slow down faster. And bigger parachutes and these other devices would allow us to land something like Curiosity, land at one, two, or even higher kilometers above sea level.

Or zero, I should say. What all of this says to me, all of this amazing work and what you guys are continuing to develop, it really puts the lie to, you know, folks who like to say, ah, if we really wanted to get people to Mars, why aren't we doing the research? Why aren't we doing the work to get there? It sure sounds like, at least here, with this system, this work is very much underway. Yes, and not just here at JPL. There are other places at NASA where people are working other tricks.

For example, deployable decelerators or deployable heat shields, inflatable heat shields. Parts of NASA are working closely with SpaceX on their return or their first stage, which is a supersonic propulsion test, really, of that technology. So we are trying to mine as much as we can. And throughout NASA, we are really taking this problem seriously of how to get bigger things to Mars, including someday people. So this is going to carry us out for some decades into the future and maybe, maybe get humans there.

Knock on wood. Yes. That's our intent. Rob, it is always a great pleasure to talk to you. Thanks for coming back on. Thank you, Matt. It's great to talk to you too. Rob Manning, he is the chief engineer.

Now he goes from chief engineer job to chief engineer job. Now it's for the low-density supersonic decelerator project that we've been talking about. Nobody knows more about or has had greater success in getting stuff down to the surface of Mars. We'll be right back with this week's edition of What's Up. It's one of those rare occasions I am sitting across from the Director of Science and Technology in the Planetary Society studio slash meat locker. But that's how we have good steaks on hand at all times. That's important. It's Bruce Betts, which means it's time for What's Up.

It's good to see you. Be good to sit across from you, and I can hand you your gift. Way too easy. Yay, when do we do that? When do we do that? You know when it happens. It's not for a few minutes yet. So let's get through the rest of it, and you'll get your present.

All right. Sheesh. So Venus, super bright. Low in the west in the evening. Jupiter, gradually getting closer and closer to it. High in the south in the early evening. In a few months they'll be partying together. Right now, although it's going to be really tough to see low in the west, you need a really clear view to the horizon. Not that long

after sunset, in just the right timing, you can see Mars and Mercury very close together, particularly on April 21st and 22nd. Mercury will be the less red, the white one that's much brighter, and Mercury will stay up through mid-May. Mars will keep vanishing away. On to this week in space history. In 1970, Apollo 13 returned safely to Earth after a recreational jaunt in the heavens. Yeah, let's do this again sometime. recreational jaunt in the heavens.

Yeah, let's do this again sometime. And then in 1972, this week, Apollo 16 was launched, off on its way to successfully land on the moon. On to random space fact! Captured with a grandeur that Skype just isn't up to. I'm sorry. So after Uranus' discovery, it was six years before the first moons of Uranus were discovered. But after Neptune was discovered, it was only 17 days until its largest moon, Triton, was discovered. Just better technology by that time?

It was many decades later, so I'm guessing it was a combination of better technology, and Triton is just a heck of a lot bigger and brighter than the Uranian moon. So even though it's much farther away, it probably helped a lot. Another great random space fact. And by the way, I watched the one you did in this very room about why you get a blood moon when there's a total lunar eclipse. Very funny. Very clever.

Cool. People can check out all those at planetary.org slash RSF or on our YouTube channel. There's even a refrigerator in it, which makes us feel right at home at the moment. There is indeed. Okay. In the contest, I asked you, what constellation appears on the flags of Australia and New Zealand? How'd we do? Huge response.

This is such fun. I put this out there on the website. It said, all right, you patriotic southern hemisphere types. And boy, did they turn out. We got a whole bunch from the folks down under. First of all, though, our winner, not from down under, from Champaign, Illinois, a first-time winner, Nicholas Hess. He said the Crux Constellation, also known as the Southern Cross. What else? Yes, indeed. So, Nicholas, we are going to send you a Planetary Radio t-shirt, and thanks for entering. All

right. Now, first of all, some of those folks from down there on the bottom half of the planet or the top half, if you turn us upside down. This from Luke Raspursek. Luke Raspursek. He says, I can triple down on my Southern Hemisphere credentials. The Australian flag features the Southern Cross, as does the state flag of Victoria. And the main train station in his hometown of Melbourne is Southern Cross Station. Wow. So they are.

Wow, very, very impressive. They are. They are all about the crux. All about the crux. Triple crux. Just to represent the Kiwis, we will mention this single one. There were many others. This one is from Carrie Hartley in Christchurch, New Zealand, who first of all says, Kia ora, Matt and Bruce.

Hello from Christchurch. Thanks for showing some love to us Southern Hemisphere folks and for keeping us all inspired. She mentions that the Maori name for the Southern Cross is Te Punga, the anchor of the canoe, Waka Constellation, or Te Waka Otama Ororiti. Wow, you did that very nicely. Says you.

The Maori now have declared war on me, I think. We'll see. Anyway, thank you for the message. This one, boy, they were coming in from all over the world. From a regular listener, Wojtek Navilek in the Czech Republic, he says that he noticed that the Australian flag version of the Southern Cross has one more star than the one for New Zealand. And he draws from this, probably New Zealand has worse light pollution. I'm sure that's the reason.

This actually came from a whole bunch of people, Don Campbell, a whole bunch of others, who basically said, thanks a lot, Matt and Bruce. Now I'm going to have that damn David Crosby singing in my head for the next week. Oh, gosh. Wow, I feel terrible. Mark Little had a twist on that. He said, any chance you guys could sing a few lines of that Crosby, Stills, and Nash song? There might be a Planetary Radio t-shirt in it for you. Last one, I promise. This from Andrew Jones

in Finland, but he's a fan of English cricket. He says he also knows the Australian national team sings Under the Southern Cross I Stand after victories. He says they've sung this many, many times at our expense.

So there you have it. Wow, that was a very lovely international response. Wasn't it? Yeah. I know that was just a sampling. Well, this one goes out to all our listeners in the Neptune system. Let's hear it, Neptunians. And Tritonians.

Triton, that large moon, that wacky moon, the biggest moon in the solar system that orbits retrograde, going the opposite way the planet's rotating. What is its orbital period? What is Triton's orbital period? Go to planetary.org slash radio contest. Get us your entry. All right. You have until the 21st. That would be April 21st, Tuesday at 8 a.m. Pacific time to get us the answer.

Here's the prize. It was so popular that Jim Bell has gone out on a limb and gotten us a few more copies of his book, The Interstellar Age, his wonderful personal account and beautiful general history of the 40-year Voyager mission, and he will sign it once again. Speaking of prizes, do you remember on last week's show what you said we should all think about uh no of course no lip wait lip balm yes that's right lip balm so i was at jpl right this week to capture the conversation that we listened to today right so here is what i picked up for you this time from the jpl store oh get out get out. That is so cool. JPL lip balm. Giant JPL, red on black.

Oh, there you can hear it. I love the sound of your cap, don't you? Ah, yeah. Let me... Okay, you go ahead and do that. Oh, it's space flavored. Cheese? Green cheese? Say goodnight, Bruce.

Goodnight, Bruce. Oh, I'm sorry. Everybody go out there. I'm so excited. I can't think straight. Everybody go out there and look up at the night sky and think about your favorite sound-absorbing material. Thank you and goodnight. Actually, that's kind of a weird flavor.

What does it say on the side there? Feel the love. I kid you not. It says feel the love and then it says spearmint.? Feel the love. I kid you not. It says feel the love, and then it says experiment. We feel the love. He's Bruce Betts, the Director of Science and Technology for the Planetary Society, who joins us every week here for What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by the Mars Landing Members of the Society. Danielle Gunn is our associate producer. Josh Doyle created our theme music.

I'm Matt Kaplan. Join us next week at the Planetary Defense Conference, Clear Skies.