Planetary Radio: Space Exploration, Astronomy and Science - Building Our Future on Mars

Episode Date: March 18, 2020

How will we build the structures, roads and landing pads humans will someday need on Mars? Civil engineer Peter Carrato has been building grand structures on Earth for decades. He says the skills we’ve learned over thousands of years are well-suited for the much more challenging Martian environment. Planetary Society CEO Bill Nye the Science Guy returns with a message of care, hope and vision for our troubled times. And a bacon asteroid is just one of the absurdities Bruce Betts and Mat Kaplan discover on the way to a new What’s Up space trivia contest. Learn and explore more at  https://www.planetary.org/multimedia/planetary-radio/show/2020/0318-2020-pete-carrato-mars-civil-engineering.htmlSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Building our future on Mars, this week on Planetary Radio. Welcome, I'm Matt Kaplan of the Planetary Society, with more of the human adventure across our solar system and beyond. I hope you're all staying safe and healthy. Want to spend a few months or a lifetime on the Red Planet? You're going to need a home, a garage, a place for rockets to land and take off, maybe a few roads. Sounds to me like you could use a civil engineer, and I've got just the guy for you. Peter Corrado will tell us how we'll build that future.

Bill Nye is here, too. He'll join me right after we get a few space headlines from the downlink. Join me right after we get a few space headlines from the downlink. A bacon asteroid and other absurdities are also ahead when we're joined by Bruce Betts for What's Up. You probably know by now that the downlink has entered a new era. Planetary Society editorial director Jason Davis has been joined by other colleagues to create this weekly collection of news, fascinating facts, and updates about the Planetary Society itself. You'll always find the latest edition at planetary.org slash downlink, which is also where you'll find a link to get the free newsletter version delivered to your inbox each week. Here are those headlines I promised, beginning with one less mission heading to Mars this summer. Europe and

Russia's ExoMars won't be ready for launch in time for the window that opens in July. It will be two years before Earth and the Red Planet are again in the right spots. NASA's 2020 Mars rover, now known as Perseverance, a Chinese mission and one from the United Arab Emirates, are all on track. NASA's Orion spaceship is back at the Kennedy Space Center in Florida. The capsule-shaped vehicle has completed all of its testing. Now it will wait for the first Space Launch System rocket to send it toward lunar orbit. That is now not expected till 2021. Speaking of the moon, China's Yut U-22 may soon set out on a

pretty amazing journey. Another one, that is. Officials say that little rover could attempt a nearly two-kilometer drive to some far-side rocks that scientists are very curious about. Want more? Planetary.org slash downlink. We poor earthlings are facing so many challenges right now. I decided to invite Planetary Society CEO Bill Nye back for a brief conversation about things that matter, things on the personal level and things on the grandest scale that exists. Bill, welcome back to the show. It's an interesting time, and I will note that we are speaking to each other in a virtual sense where we're much more than six feet apart. Even with this terrible pandemic and how we are all trying to adapt to it on our minds, our minds are capable of still looking up at the sky and wondering about the universe. looking up at the sky and wondering about the universe.

Well, we want to know where we all came from. What are we doing on this planet? And who knows, Matt, when you understand the nature of mass and energy in the cosmos, maybe you'll understand how living things work. And I'll give you an example that wasn't my idea, but is amazing. These guys trying to understand dark matter, the distribution of the matter in the universe that we cannot see yet somehow produces this gravity that is pulling everything apart. That somehow follows the same pattern as slime molds. Everybody loves a slime mold, Matt. Everybody loves a slime mold, Matt. What in the world is this? I remember this from many years ago.

I did not become a professional life scientist. It's a single-celled organism with many, many, many thousands, tens of thousands, hundreds of thousands of nuclei. So it is a eukaryote. Eukaryote is a cell with a nucleus. It means it's from the Greek word for having nuts, having kernels. Not to get us in trouble there. Having kernels.

I get you. Yeah. And so the slime mold finds its way, slime molds find their way around the forest floor, eating bacteria and fungi by moving the way amoebas move, amoeboidly their way around. Apparently, the way dark matter seems to interact with itself follows the same pattern. So these guys, a slime mold lives in a gravity field, all the ones that we know about. But they had to somehow make it a three-dimensional model. And they did. It's crazy.

And it works. It works. It actually, you can match it up to the reality that they've seen with tools like the Hubble Space Telescope. And sure enough, these filaments of dark matter. And Chandra X-ray. Yeah, Chandra X-ray. And so, everybody, I just reflect on this all the time. When my grandparents were my age, they had become aware of the practical use of relativity.

When they were little kids, no one had discovered relativity. No one had any idea it was important, where the speed of time, as I like to describe it, changes with gravity, or your speed relative to a gravitational object, or something in the space-time that has gravity. Whoa, dude! Anyway, they lived to see nuclear weapons developed, and nuclear power power and just understanding of the quantum, of quantum electrodynamics and so on. They live for all that. So I just reflect all the time about dark energy and dark matter, Matt. Will there be a time, 20 years, 30 years hence, where there are practical applications? Dark matter is understood so well that there'll be practical applications.

There'll be the equivalent of a laser or an ultrasound machine or magnetic resonance for scanning your brain or what have you. Well, something like that emerged from this kind of research mixing astronomy and what people like to call astrophysics, the physics of stars, with the chemistry of life. It's amazing. It's amazing. And as the kids say, how cool is that? The kids say that, Matt. I listen to them now and then saying that. It's pretty darn cool.

Thank you, Bill. I think I'll hold out for warp drive coming out of the next discovery from slime molds or something else that we share this planet with. But really, it's this crazy pattern where it seems to have agency. It seems to have a plan. It moves to where the food is. And then when it's time to reproduce, it produces spores. And the DNA of slime mold is a fraction, a 10,000th of the DNA that you and I have. I mean, it's something like 187 base pairs instead of 3 billion. Like, what? Or maybe it's, if you talk about kilobases, 30,000. That's just amazing to me. That's amazing. It shows you how little you need to get by. What do we put in right here, Matt? Old boss joke. A joke about my old boss right there.

How the guy functioned with so little. It's amazing. Life finds a way. Bill, I'm giving you a virtual elbow bump or maybe a live long and prosper. Oh, let's do both. Yeah, live long and prosper. Yeah, there you go. I can do it with either hand. You know, our beloved Robert Picardo on the board of directors of the Planetary Society who played the doctor on Star Trek Voyager is right-handed.

I can assure you he's right-handed. He's a good friend of the society. But he can only do the Vulcan live long and prosper greeting with his left hand. Oh, that's interesting. I think that's proof of the paranormal right there. Well, that or that he needs to be reprogrammed. Just freaking subroutines.

It's always trouble. Hey, man, everybody, let's keep our chins up. Let's be together. We're all self-isolating but be sure to check on your neighbors because if we've got nothing else out of astrobiology matt the study of life here on earth and imagining what life must need to exist elsewhere we have learned that we have a common ancestor all the living things on earth slime slime molds, sea jellies, my old boss, everybody has a common ancestor. And so check on your neighbors, make sure they're doing okay,

and ask them to check on you. We're going to get through this. Thank you, Bill. Thank you, Matt. That's the CEO of the Planetary Society, which is taking this stuff seriously, but we're still looking upward. There's a NASA webcast series. I love to join when I can. I have no expertise to contribute to them,

but I'm fascinated by the content of the Human Landing Sites Study, or HLS-2 briefings. Each takes up a different aspect of what will be one of humanity's greatest challenges, putting men and women safely on the surface of Mars, supporting their work there for hundreds of days, and returning them to Earth. The most recent of these discussions was titled Paving the Road to Mars, Civil Engineering at the Human Landing Site. As always, it welcomed an outstanding selection of the people

who will enable us someday to achieve these goals. Peter Corrado was one of them. Pete spent several decades at Bechtel Corporation, rising to Corporate Manager of Building Information Modeling and Virtual Design and Construction. He is now a Bechtel Emeritus Fellow and a Fellow-in-Life member of the American Society of Civil Engineers, also a Fellow of the Institution of Civil Engineers in the UK.

As you're about to hear in this unique Planetary Radio conversation, Pete has given a lot of thought to how we will build that future on Mars, the Moon, and elsewhere around the solar system. Pete, thanks very much for joining us on Planetary Radio. future on Mars, the moon, and elsewhere around the solar system. Pete, thanks very much for joining us on Planetary Radio. I got to say, I thoroughly enjoyed your contribution to that NASA-sponsored discussion just a couple of weeks ago. It's a good thing that you were there. I mean, all of the presenters in that webcast were terrific, but I think you were the only one who has actually built a structure on this planet to say nothing of Mars. So let me start there. How can our knowledge of

construction on Earth prepare us for building on Mars or perhaps the moon? Well, Matt, that's a great question. And the answer any engineer will give you is it's absolutely essential preparation. There's a story told about bridge builders, early bridge builders, walking through the woods and they see a tree that's fallen down across a creek. They walk across the fallen down tree. Then they find a bigger river, so they go and they try and knock a tree down across it. And that works. So they go and they try and knock a tree down across it. And that works.

And they walk across it. And then they find a much bigger river. And they try and knock a bigger tree down across it. And they get out on it. And that tree breaks. So they then have to go and invent something called a truss. So the moral here is engineers work based on what they've seen, their experience. And then they push the envelope of that experience until it doesn't work anymore. And that's how they invent new engineering structures. So

I personally believe that when we go to build structures on the surfaces of the moon or Mars or any other planetary body, we will be bringing our engineering experience from the Earth with us, whether we do it consciously or not. Do we know enough now to go to Mars and build some of the structures that were being talked about in that webcast? Absolutely, we can. Actually, I believe much more readily than building on the moon because the geology of Mars is more similar to that of the Earth, specifically when it comes to sedimentary rocks. So if you go and look at historical structures, let's say the pyramids in Egypt, these are built out of limestone, which is a sedimentary type of rock. And you can find sedimentary rock structures that are thousands of years old in many places around the Earth. That type of rock is prevalent on Mars. And literally picking them up and stacking rocks together, you can build serviceable structures.

And you have to define what serviceable is that will last for thousands of years. Serviceable might mean let's say I want to protect a robot from a solar flare. Well a robot doesn't need a pressure tight structure to take shelter in. So you could create a stacked stone structure that would absolutely provide shelter for a robot from certain events that it needs to be protected from. One of my favorite quotes,

and it was something you said during that webcast, was that when you see these wonderful images coming back from Mars that show us layered sedimentary rock, that it had you drooling. Well, that's because I've been spending a lot of time looking at the moon. want to go and build on using the local resources without a lot of, let's say, modification to what you pick up. You can see, and these images have been out for decades, different images of villages on the moon. And some even look like you just took Manhattan and moved it to the moon. And maybe thousands of years from now we'll do that. But in the near term, if you're not bringing your habitat with you to inflate or somehow deploy, to take lunar materials and turn them into a habitat will require a large amount of energy to melt them or modify them in some fashion so that they turn into a

structure. So when you go to Mars and you see these beautiful outcrops of sedimentary rock that, you know, you don't even have to remove regolith to expose. They're just exposed and you just basically walk your robot up to it with some very simple tools like a pick. Start knocking out blocks of material that you can start stacking together and producing real structures. You mentioned the pyramids. You showed us a picture of another structure, which I had never seen or heard of. And it was something that looked like apparently it's about 3,000 years old in Ireland that was constructed just the way you're talking about.

That's correct. That's just, again, another example of people stacking stones to produce structures. And you can find examples like that. Look at South America, look at what the Aztecs did or the Incas. And I'm sure you could find similar structures in Asia as well. To me, the pyramids are just a very unique analog or something you could compare to the only real building that's been done off of this world, and that's the International Space Station. So as background, no one has built anything on the moon. It's the only place we've gone, or Mars.

Haven't so much as stacked one rock on top of another. True enough. So the space station took almost as long to build as the pyramids did, as the Great Pyramid did. The Great Pyramid took about five years longer. The space station costs $150 billion to build. It has a service life of about 20 years. The Great Pyramid was built entirely out of in situ resources. And current design life is in the

order of 5,000 years. So kind of the message is, you don't want to build the spaceship on the surface of the moon or Mars, you want to and have to use the resources you find there. And this, of course, is a huge topic, in situ resource utilization. You've already talked about this with the presence of these sedimentary rock layers on Mars. Other people talk about them in terms of creating the air that we'll need to breathe up there, the water we'll need to drink, and the rocket fuel we'll need to leave Mars when we decide to do that. Obviously, ISRU is something that you also think is going to be essential. That's correct. As you pointed out, there's different ways to look at the local resources. I look at them from a building point of view. The other way, of course, to look at it is,

as you mentioned, to modify those to produce breathable gases or water or fuel. You could even, of course, as time progresses, get into the production of metals, extracting rare earth elements, all kinds of things like that. But I like to look at it from, what can I make out of this stuff? I'm at the very low-tech end of this. So we talked about stacking stones to build a habitat. If you want to see something to really get you interested in what these structures could look like, there's a structural form on the Adriatic coast of Italy called a truli, T-R-U-L-I. That's the plural of Trullo. And it is stacked stones. The roots are very old, but the actual application is recent because the residents of this one particular province are not taxed on Trullos

because the government does not consider them permanent structures. So they're a very popular housing form. And some are quite beautiful inside, and you can go vacation in one if you'd like to. The other place you can use these resources are in, let's call it horizontal structures. Easiest way to think of that is a road. So building a road is a very well-worn technique within the toolbox of the civil

engineer. And the best roads, in my opinion, of course, have the roots in the Roman roads, many of which are thousands of years old and still quite serviceable today. The key to a Roman road is the depth at which you prepare what's called the sub-base for the road. So a Roman road might have, you might have to dig down four or five feet and it has certain attributes as far as friction and smoothness and things like that. You've probably ridden it on a road which was not prepared with that deep a sub-base, and it's ripply and it's got ruts in it, and it just shows that even on Earth we don't necessarily prepare the roads the way we would have done in ancient times. So on the Moon or Mars, there's going to be a need for roads.

Those two heavenly bodies are dramatically different when it comes to roads. The Moon has lots of dust on it, various thicknesses of dust layers. And the only driving that's occurred on the moon with the rover kicked up huge amounts of dust. And it's recognized that this is obviously not what you're going to do in a permanent settlement. So you would have to prepare a wearing surface that you could drive on which would not produce as much

dust. So how would you go about doing that? Now I'm in the land of pure conjecture here. So to create a road on the moon, the steps to creating a road anywhere start out with a route survey where you say, I want to go from here to there. And you look at various ways you could do that. By that, I mean, you know, is there a mountain in my way and do I want to put a tunnel through the mountain or do I want to go around the side of the mountain? So there's various ways you can prepare your route. So on the moon, you probably want to go around some of the deeper craters

and you might want to build a causeway or fill in part of a shallow crater to go over that crater. So the first thing you do is you develop your route. Then you have to basically smooth out that route. So this is cutting material, removing material from the surface of the planet, and filling, where you would take some of that that you took away from a mound and say put it into a crater a good civil engineer will do what's

called balance the cut and fill so you want a route where whatever you strip away you go to another place along the route and you fill in with it and And that saves you energy, saves you having to get rid of material. It also assumes that whatever material you take away is material you can use to fill, and that's not always the case. So once you've smoothed out your way, now you start to prepare the roadbed. So I now have my path, and I have it smoothed out.

So now I want to start covering it with layers of gravel. And this would be the simplest way to do it on the moon. So you need to collect in situ material, run it through a sieve, like the thing you took out on the beach where you put sand in and shook it out. You have sieves with different hole sizes in them so that you get a range of sizes of material and you would want to start your first layer to be a little bigger than a pebble say about an inch and a half in diameter average so you laid out

a layer of that that would be four to five inches thick. And then you take a heavy smooth roller and roll over the top of that. Then you would put down another layer and now it'd be slightly smaller, say three quarters of an inch in diameter. And again, three or four inches thick and you roll that out. And then maybe on the top, you go to something, say about an eighth of an inch in diameter. the top you go to something say about an eighth of an inch in diameter and now you have a pretty robust wearing surface you could smooth that surface you could on the earth we would put asphalt down now or concrete people talk about sintering on the moon where you basically go and melt the rocks together i'm not real excited about it. It's a highly energy intensive operation. And I'm not sure the benefit to the vehicles for having that smooth surface. I think

a nice, well-graded gravel surface would serve the purposes for the early residents of the moon. And a similar road structure could be used on Mars. I'll be back with civil engineer Pete Corrado in seconds. Hi, I'm Yale astronomer Deborah Fisher. I've spent the last 20 years of my professional life searching for other worlds. Now I've taken on the 100 Earths project. We want to discover 100 Earth-sized exoplanets circling nearby stars. It won't be easy. With your help, the Planetary Society

will fund a key component of an exquisitely precise spectrometer. You can learn more and join the search at planetary.org slash 100 Earths. Thanks. Welcome back to Planetary Radio. I'm Matt Kaplan with more from civil engineering expert Pete Corrado. Short of building a road, I mean, civil engineering expert Pete Corrado. Short of building a road, I mean, there was discussion in this webcast of the possibility that because of the rockets in the descent vehicle taking humans down to the Martian surface might kick up so much dangerous debris that we might have to pre-construct a landing site, a pad. Would this be the same kind of structure you've just described for a road? Or sounds like you wouldn't want gravel on top.

No, you wouldn't. And a pad, I believe, would be one of the most valuable structures either on the moon or Mars. And exactly for the reason you described, that descent, the rocket engines on descent are bringing, obviously, a lot of energy in a very concentrated space. And they will get airborne lots of material that's impacted by that engine. So the engine will do two things. It will eject material to the sides. If you have multiple engines, it will actually start churning up the material in the space between the engines, potentially bringing up damaging materials into the engines themselves.

And it will scour out the area it's landing on. and it will scour out the area it's landing on. So if it's not robust, competent material, you're basically digging a hole to land it. And some of your colleagues actually showed us computer models done of exactly this with multiple engines. It was pretty scary stuff. There's a lot of study on this done at the University of Central Florida.

Some of the images that come out of the researchers down there are quite exciting and should be potentially scary. They've actually gone through all the video of, say, the Apollo landers. And when you see their presentations, they will run these slow-mo videos and go, oh, look, here is a rock leaving at 75 miles an hour as it flies out of there. So to get a prepared landing surface, especially if you're going back to the same place over and over again, this really hasn't happened yet. I mean, all of our trips are exploratory, where we're

going, okay, we've been there, let's go somewhere else. So there's no opportunity to build a landing pad. If you're going to say, well, no, I'm going to mine ice on a glacier on Mars, and I'm going to keep coming back over and over again. Now having a landing pad makes a lot of sense. over and over again. Now having a landing pad makes a lot of sense. So will it be different than the road? Absolutely. A road is very low energy put on the road. And I would think off world, you're talking if a vehicle can go 30 miles an hour, that's probably a really fast vehicle on Mars. So you're not ejecting a lot of material when you're driving at 30 miles an hour, ejecting a lot of material when you're driving at 30 miles an hour, even on a gravel road. The other thing is it's not bringing any heat. Heat is a big challenge here, but we know how to do this on the earth. There's a couple of ways. I've had the opportunity to work on launch pads.

Most are very sophisticated because the launch energy is much higher than the landing energy. A large steel chute, and the chute is actually made of tubes with very fine holes on the top of the tube where the flame would impact it. flame would impact it. So this chute, before they launch the rocket, they start pressurizing it with water and you get this spray of water coming out of the chute. When the rocket flame hits the spray of water, the water turns into steam and the steam actually protects the metal from the flame impacting it. So the flame follows the chute and goes out to the side. Yeah, we've seen this, of course, rockets through many decades, Saturn V and the space shuttle. You can see those flames shooting out of these off to the sides of the pad. Right. So a water-enabled liftoff is probably many, many decades in the future.

So for right now, what you need is you need a material that is temperature-resistant. There are temperature-resistant materials. There's a concrete that goes by the name of refractory concrete or refractory materials. So these are ceramic or brick-like materials. They're used all the time in steel mills, for example. When you see that big ladle of steel, you might say, well, that looks like a steel ladle full of molten steel. How does that work? Well, that's because that ladle is lined with refractory materials. The steel is there for the strength. The refractory material, which is, in that case, brick-like,

is there just to resist the heat. The landing and launch pads will need to be built of refractory materials, which you can find. They're actually quite available on the moon, and I'm sure you can find them on Mars. It would take a little bit more effort than just going and finding some sedimentary rock and stacking it together. This will be a little bit more of a challenge from the material science point of view. You made another great point.

You've made several during your presentation, your portion of that NASA webcast. And it was that before you do any of this construction, you've touched on this already, you got to know where you're building. And you gave an example, and it was actually an image looking back from one of the Mars rovers at soil that it had crossed. And it made your point that soil can change from meter to meter, obviously on Mars as it does here on Earth, and that you better know a lot about the site that you plan to build on. That's the key to success for any large construction project, whether it's on this world or some other world. Personally, I've been associated with too many projects where not enough soil borings were taken,

someone built something, and now it's not performing the way it was supposed to be built. So it's a tried and true lesson. The reason you have those terrestrial experiences like that is because soil borings, even on earth, are expensive to perform. Soil borings off of this earth are going to be much more expensive. So there'll be a natural desire by, let's call it project management, to limit or eliminate the need for any soil borings. As we say in the business, I've seen that movie too many times. I want lots of soil borings.

You gave a great example, a very famous example. It would take us back to Italy. You know the one I'm talking about. Yeah, so Leaning Tower of Pisa is probably the most universally known example of what happens when you don't have proper soil investigation when you build an iconic heavy structure. Of course, we don't want to be doing that off the world here. Well, let's ignore it for the moment that some of this evaluation and construction may have to be done before humans arrive. Maybe we'll come back to that. But what tools do we need to take to these places, the moon or Mars, so that we can both evaluate the soil that we're going to be building on and get the construction done? I mean, there must be some

stuff that we're not going to be able to get out of materials that are already there on these worlds. The challenge, and there's different ways to overcome the challenge is what can I bring with me? There are commercial spaceflight companies out there that are talking about payload capacities measured in hundreds of tons. You can bring a lot of gear with you when you have 100 tons to play with. If you're looking at a Mars rover,

which is about a ton, then you're not bringing a lot of tools with you there. So what can you do to do simple soil investigations using limited capacity of cargo? There's actually quite a lot you can do, and it really depends on how heavy the structure is you want to build. Most of the first structures will be very light. Even if you're stacking stones, you're not going to stack them that tall. If you're talking about inflatable structures or deployable structures, again,

they're going to be very light compared to, say, a large concrete structure on the earth. So that means you can probably limit your soil investigation to just the upper layers of the soil. So to investigate the upper layers, there are actually rule of thumb techniques, which most civil engineers have been taught. And it's kind of funny, we'll use the term rule of thumb. the simplest technique for checking bearing capacity on a terrestrial soil is you take your thumb and you push it into the dirt and you see how far your thumb goes in. Actually, if your thumb just goes to where your fingernail is touching it,

you can build almost anything on that. That's about what we call about 2,000 pounds a square foot of bearing capacity. Wow. If your thumb goes in much further, then you know, okay, I'm going to have to do something light or I'm going to have to improve the ground. There, of course, are calibrated tools that mimic that. The simplest one is something called a cone penetrometer, which is nothing more than a metal cone of a known weight or something you put on the ground, point down, and push with a known force and see how far it goes in. It's the same as the push your thumb in test. And based on that, you can do a lot of very lightweight structures. You need deep soil investigations as your soils get heavier and the weight of the structure you're

putting on the soil has an influence on soil layers that are at greater depths. So you can think of the way the load from a structure on the surface spreads out into the earth as you go deeper. If you assume that if you draw a 45 degree line from where the foundation is downward into the earth, projecting away from your structure, that's roughly the way the soil force will spread out. So say at the surface of the earth, you might have a bearing pressure of 1,000 pounds per square foot. As you go down two feet, the bearing pressure will be smaller because the force will have spread out at some angle, 45 degrees or so, so that the layers as you go down can be softer than the surface layers.

So if you have something really heavy, it will have a very deep influence. And if you have a soft layer that's, say, 10 feet below the surface, you start to get that leaning tower of Pisa effect. What are the other tools that you would tell the first humans headed to Mars that they'd better bring along with them if they want to put up a structure? Well, I think the first humans will have a real good idea because the real key is what are the first robots going to do? Ah, yes. So to me, a robot is a tool carrier. It doesn't have to look like Robbie the robot and walk around on two feet, although it'd be nice to have some of those.

To me, you need a whole civilization of robots, some that crawl, some that roll, some that leap, some that walk. Designing those are the tools you want to bring. So a hauler, a digger. There used to be a video game called Lemmings. If you've ever played that, you could think about, oh, I need a miner and I need a lifter. In the Lemmings game, you got many, many different challenges,

but you only had like eight or 10 different kinds of Lemmings. And you just put them together to achieve whatever goal you're looking for. It's kind of that sort of game I see with the first waves of robots. Are you fairly confident, based on all the work that's being done on Earth, that robots will be capable, by the time we're ready to send them, of on their own building the kinds of structures we'll need before the humans get there? I would say the biggest challenge is that landing pad because it's not just a structural problem, it's a large material challenge. And it might even be that you might need to bring refractory material with you, which would be not ideal because that material is quite heavy.

It's like shipping concrete to the moon. It's not something you want to do. It's something you want to avoid. The actual robots, I mean, you can see the rovers on Mars, to me, are just miracles of mechanical engineering. They show what we can do. The people who built those, if you said, look, I need you to build me a mobile crane that can lift 20 tons, or a shovel that can dig three cubic feet of soil, or a truck that can haul 20 tons of material, I'd say they were definitely up to the challenge. The biggest challenge I would see for robots in the near term are trying

to extract water ice on the moon from the permanently shadowed regions because the temperatures are just so incredibly cold. I'm not sure what even works there. Wow. When the humans are finally ready to go to Mars, would you be advising NASA that they ought to include a civil engineer among them? Actually, we did recently within my I did a little thought exercise. If you had to make up a 20-person crew to go to Mars, and the key is you have to spend nominally 450 days on the planet before you have an opportunity to return, who do you bring?

And my list was about 60% engineers, civil engineers, mechanical engineers, electrical engineers, chemical engineers, because you're going to be making fuel. You're going to be generating power. You're going to have a lot of robots. Things are breaking. I need an electrical engineer to keep my power grid up. I need my chemical engineer working on the process plant to produce methane.

I need mechanical engineers engineer working on the process plant to produce methane. I need mechanical engineers keeping my robots happy and keeping all the pumps and condensers and valves working. You know, the balance of the mission is doing science and exploration with a smattering of folks whose job it is to keep society going, like maybe a librarian or an archivist who's documenting this historic 450-day mission. Or even as simple as a barber who's cutting everybody's hair. A hair engineer. Well, you'll cross-train the chemical.

They can probably figure it out. former employer Bechtel back in 1942, which says a lot to us today about the challenges that are going to be faced by these humans in this environment that's going to be much more difficult than anything ever faced before. Could you talk about that? Everybody who has ever worked for Bechtel since 1942 has seen this sign and has a copy of it somewhere, either on their desk or in their computers. In big bold letters at the top of it, it says, this is no picnic. And it describes environmental challenges that the people doing the construction will face, rivers of ice, temperatures from minus 60 degrees to 100 degrees.

Gnats and mosquitoes will not only be annoying, but will be life-threatening. It says, if you're not prepared to work in these conditions, do not apply. And this was a sign for construction workers to build the first highway into Alaska at the beginning of World War II in order to move military material up there to blunt any invasion threats from Asia. That philosophy still has to apply. The people who've gone to space so far are, you know, they're pilots, they're geologists, they're explorers. The next wave of people have to be builders to go there and expect stuff to break. Like, I don't even believe this is going to be working. I need bailing wire and duct tape and three different hammers and stuff is just going to break and I know I can fix it.

To me, it's maybe a different philosophy you have to take with you. Pete, if we were ready to go tomorrow and Administrator Bridenstine came to you and said, Pete, you're the guy. You've got the skills. We need you to build this stuff on Mars. Would you go? If I was a younger man, I would be very tempted. I had a reputation when I was working full time. I went anywhere. People would walk in and say, okay, we've got a problem with some bolts in Kazakhstan. Who's getting on an airplane? I always had my hand up.

Let Pete do it. And there's a breed of people like that. And there are plenty of engineers out there who hate the office. They have to be in the field. And this is the field. This is where you go to solve the problems to make it happen. I could stop there, but I saved one example. You actually contradicted yourself because you said that we've never built anything on another world. And yet in your talk, you gave us an example of the only construction project that you could come up with. And it was on the moon about 50 years ago. I'm glad you were paying attention, man. So as I was preparing for that talk, I sat down and asked myself,

so what have we built? What can I use as past experience to talk about? And I do a lot of work in the writing and updating of building codes in the United States. What has the building code ever been used for or could have been used for on the surface of the moon or Mars? And there is actually one such item, and it's the flagpole. So every Apollo has gone and set up a flag,

and there's a section within the International Building Code, which is the building code used to design whatever structure you're in and listening to this in right now. There is a section in there, if you Google it and search for flagpoles, where it talks about lateral soil restraint at the bottom of flagpoles. flagpoles. And lo and behold, when Apollo 11 landed and set up their flag, the mission report says they had trouble pushing it into the ground and were having trouble with lateral resistance for the flagpole. So we had an example of the very first humans up there building the structure according to a building code and sending back a construction report saying they were having trouble meeting the code. Pete, I hope that you and I are both still around when the first flagpole is successfully erected on Mars.

Thank you for this. We've done this show for 17 and a half years now, hundreds and hundreds of programs. I don't think we've ever had a discussion quite like this one. It has been absolutely fascinating. Thank you for sharing this expertise. It was my pleasure, Matt. Thank you. Distinguished Civil Engineer and Bechtel Emeritus Fellow, Pete Corrado. Time for What's Up on Planetary Radio. We are joined by the Chief Scientist of the Planetary Society. That is Bruce Betts, who is at home, exactly where he should be,

and exactly where you should be, listening to this right now. I'm right, right? Right. Right, right. Right. Right. Right. All right. I hope you're not going too stir-crazy there. Are you getting to look at the sky or what? I mean, listen to me. I'm just growling with ferocity. That is one of your dogs, right?

That's not you. It's a cooped up dog. All right. Yes. Yes. And there's the other dog. So who knows what noises we may hear. So who knows what noises we may hear.

If we were to go outside with proper precautions and social distancing, what might we see in those things that are so far away? We probably don't have to worry about them giving us anything. We would see planets and stars. I mean, we wouldn't because we live in Southern California and it's just it's oddly cloudy all the time. But for those who don't have clouds, check out the morning pre-dawn east. We have Jupiter, Mars, and Saturn doing a little dance. Jupiter is the brightest of the three. Mars is near Jupiter. Mars being reddish, Jupiter being really, really bright.

And then Mars is sliding down towards yellowish Saturn, and they're all very close together. Mars will be snuggling with Saturn. It's the technical term on the 31st of March. And if you got a clear view to the horizon, way down to the lower left is Mercury. In the evening, we of course have Venus dominating the western sky. It's moving up and will line up with Aldebaran and Taurus, and then farther to the upper left, Betelgeuse and Orion. And the crescent moon, the very fresh crescent moon, joins them between Venus and Aldebaran on March, well, it's March 27th and 28th it's near Venus. We move on to this week in space history. It's Soviet-Russian week, not officially.

1965, the very first spacewalk taken by Alexei Leonov. Tragedy in 1980, a rocket explosion on the pad killed 50 people. And then 2001, Mir space station reentered the Earth's atmosphere. That's such a great story about Alexei Leonov, who was just a heroic cosmonaut. How he could barely get back into the spaceship, into his capsule because his suit had expanded so much. It was some scary stuff. Scary stuff. A lot of brave people. We move on to Random Space Fit. You'll like this, Matt.

There's an asteroid named Bacon. Did you know this? No. Where is it and how do I get a piece of this? Well, first, before you get too excited, oddly enough, rather than being named after the meat product, it is named by English philosopher and statesman and father of the scientific method, Sir Francis Bacon. Who was named after bacon, of course. Yes. No, so it all ties back. I'm thrilled. Is this out in the main belt or does this have a chance of

striking our planet someday and there'll be a silver lining? Is it less terrifying if the asteroids named Bacon or made of Bacon? I don't know. I don't know. I honestly was so excited there was an asteroid named Bacon, I didn't check its orbital parameters. I apologize. You and me both, bro. All right. We move on to the trivia contest where i asked you where in the solar system where in the solar system is there a feature named bilbo turned out feature was a significant word

because in that list of crazy asteroids, there's a Bilbo. But I was looking for a feature on an object in the solar system. How'd we do, Matt? Well, many of you out there found that asteroid, didn't necessarily find the feature that Bruce had in mind. And that's good. You know, that's fine. Doesn't exactly fit the definition of a feature, but good on you.

Before we get into it, we had a request, literally, from Robert Johannesson in Norway. He wants to know if you or I can sing a short extract of Leonard Nimoy's Ballad of Bilbo Baggins before you announce the winner. Well, that's clearly you. Bilbo, Bilbo Baggins, the bravest little hobbit of them all. You know how I know that? This will cement. that's clearly you. Bill Bow, Bill Bow Baggins, the bravest little hobbit of them all. You know how I know that? This will cement, I think I may have mentioned this in the past,

but if you didn't know I was a nerd, I have not one, but two Leonard Nimoy LPs. Oh my gosh. There were two? That's what everyone else in the world is saying. Do you own Shatner as well? No, I don't have a Shatner. But you've got two Nemoids.

That's impressive. I do. I do. And the first one is he's in full Spock regalia too, holding a model of the Enterprise. It's fun. Here's our actual winner. And she is one of those who picked the feature on Titan. Here's her little poem to answer us.

On Titan, the sixth moon of Saturn, the names of the hills have a pattern. It's hobbits, not trolls, such as Bilbo Coles. Hence, to Tolkien, our praises must turn. The last line is a little bit free verse, but that's okay. She's a retired teacher, and her name is Maureen Benz in Washington state. She says that she found our recent Astronomers Without Borders episode, especially compelling. It's her first time entering the contest and she just wanted to give us that little limerick since St. Patrick's Day was around the corner when she sent it to us.

Here's to new frontiers. Well, here's to you, Maureen. You've won big time. You're going to be getting a Planetary Radio t-shirt from the Planetary Society store at chopshopstore.com and a Planetary Society rubber asteroid. So congratulations. Dave Fairchild, our poet laureate in Kansas, he came up with the asteroid, so it'll get equal time. Martin Watt, who works at Lowell Telescope, the skies, found a main belt asteroid about eight clicks in size, tagging it as Bilbo in the solar space frontier, matching one he'd labeled Tolkien earlier that year. Robert Klain in Arizona, Bilbo's highly eccentric orbit, it comes closer to Mars than most asteroids, made me think of you guys. Hey, wait, that was a compliment, right? Yeah, I think so.

Joseph Poutre, we hear from pretty frequently. He's in New Jersey. He said, yeah, he found the asteroid, but he also wanted to make sure we knew that there is Bilbo Mound in Savannah, Georgia, Bilbo Canal, also in Savannah, and restaurants, Bilbo Pizza, Kalamazoo, Michigan, Bilbo Pub in Bossier City, Louisiana, and my favorite, Bilbo Barbecue in Bremen, Georgia, where I'll have some bacon with that brisket, please. Actually, I'm avoiding beef, but I'm not off bacon. Also, two beetle and one wasp species, but they're mobile and so wouldn't count as features. So other than the wasps, should we try to visit all of those and maybe have Planetary Radio live at each of them? Road trip. The Bilbo tour. Did you want to say anything else about Titan? Because I guess we had a bunch of people who told us there were lots of features. There are lots of features on Titan named after Middle Earth denizens.

Yeah, the name Bilbo follows the convention that Titanian Kallis, Kalls, Kallis, I don't know, meaning hills or small knobs in geologic terms terms are named after characters in Tolkien's works. Well, we just have one more to share with you. It's Laura Weller in the UK. She says, Bilbo and Gandalf in space? I had a Lord of the Rings themed wedding. I can't believe I could have merged it with a space theme. What a missed opportunity.

Thank you, Laura. You've outner space theme. What a missed opportunity. Thank you, Laura. You've outnerded me. I don't know. Tolkien themed wedding or two Leonard Nimoy LPs? All right. All right. It's a close one. I won't call it. Maybe not. No, we'll give the nod to her. All right. You ready for more? Please. Going in a different non-Tolkien direction, into the land of stellar astrophysics, the Chandra-Sekhar limit is the maximum mass of a stable white dwarf star. Here's your question.

In solar masses, so that's the unit to use, solar masses, what is the approximate value of the Chandra Sekhar limit? Go to planetary.org slash radio contest. I used to know this limit. And so it's killing me that I can't think of it now. Because anything bigger, right, will collapse into a black hole? If you get above that mass, it'll collapse more. And it'll first would go to a neutron star.

But if you have more mass than the neutron star can handle, then it goes to a black hole. Okay. Well, regardless of what your favorite white dwarf may become someday, or whether it'll just hang around forever, you have until March 25th, probably won't collapse before then,

Wednesday, March 25th at 8 a.m. Pacific time to get in on this contest. And if you come up with the correct value for the Chandrasekhar limit, we've got a book for you, Spacefarers by Christopher Wanjic. Wanjic, I hope I have that right. Nice book recommended to me by a friend of ours at JAXA, the Japanese space agency. And we will throw in a Planetary Society rubber asteroid. And I'm afraid we're fresh out of the bacon ones. But we can just smear some on it for you.

That's a good idea. You can let us know if you win, if you want bacon grease smeared on your asteroid. Oh, God. Let's get out of here. I'm sorry. Enjoy yourself. You've broken me. All right, everybody, go out there,

look up at the night sky, and think about what else? Bacon. Thank you, and good night. He's Bruce Betts. He's bacon. No, I'm sorry. He's the chief scientist of the Planetary Bacon Society,

and he joins us every bacon here on Planetary Bacon. I mean, no, I'm sorry. He's the chief scientist of the Planetary Bacon Society, and he joins us every bacon here on Planetary Bacon. Planetary Radio is produced by the Planetary Society in Pasadena, California. It's made possible by its members who are helping to build our future in space. You don't need a hammer to help out. Join us by visiting planetary.org slash membership. Mark Hilverde is our associate producer. Josh Doyle composed our theme, which is arranged and performed by Peter Schlosser. Be safe, everyone.

Adios. Thank you.