Planetary Radio • Dec 16, 2020

What Do You Need to Make Martian Oxygen? MOXIE!

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Michael Hecht

MOXIE Principal Investigator and Associate Director of MIT’s Haystack Observatory

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Bruce Betts

Chief Scientist / LightSail Program Manager for The Planetary Society

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Mat Kaplan

Senior Communications Adviser and former Host of Planetary Radio for The Planetary Society

Mike Hecht is in charge of the MOXIE experiment on NASA’s Perseverance rover, arriving on Mars in February. The tiny device will test our ability to turn the Red Planet’s plentiful carbon dioxide into oxygen. Someday a scaled-up version may make the oxidizer that will get astronauts back to Earth. Mike also helps lead the groundbreaking Event Horizon Telescope Collaboration that captured the first image of a black hole. Want to win a Planetary Society baseball cap? Your opportunity arrives with What’s Up.

MOXIE Lowered into Rover
MOXIE Lowered into Rover Technicians in the clean room are carefully lowering the Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) instrument into the belly of the Perseverance rover.Image: NASA/JPL-Caltech
Mars Oxygen ISRU Experiment (MOXIE) components
Mars Oxygen ISRU Experiment (MOXIE) components Mars Oxygen ISRU Experiment (MOXIE) is an exploration technology investigation that will produce oxygen from Martian atmospheric carbon dioxide.Image: NASA
First Image of a Black Hole
First Image of a Black Hole The first image of a black hole using Event Horizon Telescope observations of the center of the galaxy M87. The image shows a bright ring formed as light bends in the intense gravity around a black hole that is 6.5 billion times more massive than the Sun.Image: Event Horizon Telescope Collaboration

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Mat Kaplan: It takes a lot of MOXIE to make oxygen on Mars as you'll hear this week on Planetary Radio. Welcome. I'm Mat Kaplan of The Planetary Society with more of the human adventure across our solar system and beyond.

Mat Kaplan: NASA's Perseverance Rover is closing in on the red planet. Inside the robotic explorer is an experiment that will move us farther down the road toward putting men and women on Mars. I think you'll enjoy my conversation with MOXIE principal investigator, Mike Hecht. Want to win a Planetary Society baseball cap? You'll get another opportunity when Bruce Betts visits with another What's Up report.

Mat Kaplan: The exploration of our solar system marches on. You can track it in our weekly newsletter, The Downlink. A couple of the stories have progressed even since the December 11 edition appeared. For example, Japan's Space Agency has just announced that the sample return capsule from the Hayabusa 2 probe does indeed contain material from asteroid Ryugu. The spacecraft snapped a beautiful shot of earth as it sped by our planet. We've got a link waiting for you at

Mat Kaplan: And as I record this, China's sample return spacecraft is nearing earth. Chang'e-5 is believed to be carrying about two kilograms of lunar material. NASA has selected 18 lucky astronauts for what it calls the Artemis Team. Some number of them may be the next humans to walk on the moon. We'll talk with one of them, veteran Stephanie Wilson, next week.

Mat Kaplan: MOXIE is The Mars Oxygen In-Situ Resource Utilization Experiment. If all goes well, it will soon demonstrate that one of the most important consumables for a human trip to Mars and back can be made right there, in-situ. Michael Hecht serves as principal investigator for MOXIE. He spent 30 years at JPL before moving across the United States to the Massachusetts Institute of Technology. Mike is also associate director of MIT's Haystack Observatory and deputy project director for The Event Horizon Telescope collaboration.

Mat Kaplan: Yes, a Mars pioneer also helps to lead that worldwide collaboration of radio telescopes that revealed a black hole for the first time in 2019. We get to that side of his life toward the end of the great conversation you're about to hear, but the main topic was making oxygen on Mars, something Mike hopes to attempt not long after Perseverance lands in February of 2021.

Mat Kaplan: Mike Hecht, thank you very much for joining us on Planetary Radio as we speak, not too many weeks ahead of MOXIE and the rest of Perseverance getting through those seven minutes of terror and down to the Martian surface. Is the excitement building?

Mike Hecht: Oh, it absolutely is. And one thing that reminds me every evening, and I encourage the audience here to follow up on, you walk out the door in the evening as the sun goes down and you see Mars in the Eastern sky glowing bright and red, almost even outshining Jupiter in the sky. And that's how you always know there's a mission on its way to Mars. That's how the orbital mechanics workout.

Mike Hecht: You launch before opposition when Mars is at that peak of brightness in the evening sky, and you land after opposition. So, every night when I go up and look in the sky, I know we're getting closer.

Mat Kaplan: It has been gorgeous lately. Hasn't it? I mean, I have the telescope out a couple of nights ago and we were looking at Mars, and some of its neighbors farther out. But it is spectacular to think that we are about to go there again, and that we'll be doing science and preparation for humans on Mars that has never been done before. Everybody talks about how important in-situ resource utilization will be for human exploration, but you and the MOXIE team seem to be among the first to actually hope to demonstrate it.

Mike Hecht: That's absolutely the case. Yes, certainly what we've done is a source of great satisfaction. But I always go back to the fact that NASA created this opportunity is the best proof that they're serious about this enterprise. When I first got involved in preparing for human exploration to Mars back in the nineties, Dan Goldin was saying, "We'll have astronauts on Mars as early as 2011. 15 years away," he was saying. And we're still talking about 15 years away. And why do I think this time is different? Well, that's one of the reasons. The fact that NASA was willing to invest $50 million in actually proving ISRU on Mars. That's a real commitment.

Mat Kaplan: That is such a good point. I mean, I know that you beat out a lot of other worthy projects. This space that MOXIE's taken up could have been another mass spectrometer or something like that. So, I guess it is pretty significant that NASA chose this way to demonstrate that we can make what humans are going to need on Mars when we get there.

Mike Hecht: Absolutely. It's the next great adventure after the other one that Perseverance is kicking off, which is Sample Return. And I find Perseverance such a wonderful, complex mission in that it's dealing with science today. It's investing in the future with preparing for sample returns, let's say tomorrow. And it's also preparing for the best science, in my opinion, which is when we have human scientists on the ground, let's call it the day after tomorrow.

Mat Kaplan: Ah, I love that. What inspired that great acronym, which I spelled out when I was introducing you?

Mike Hecht: The great acronym MOXIE.

Mat Kaplan: Yes, I'm sorry. Yes, MOXIE.

Mike Hecht: Because of course it has an embedded acronym in it. And even that is a story. MOXIE, of course, has the general connotation of audacity. So there are the literal interpretation of the fact that we were a long shot group when we proposed. And the fact that we proposed at all, and inspired by my JPL colleagues, was audacious, was evidence of MOXIE. Of course, the fact that we were selected even more so.

Mike Hecht: But it also had a real local resonance for me and for my institution, I'm working at Haystack Observatory up in Western Massachusetts, down the road from Lowell, Massachusetts. Growing up in this area, Moxie was a soft drink everybody knew. And in fact, it goes back to the late 1800s where it was the soft drink. The fact that we have this word MOXIE that means audacity comes from the advertisements for the soft drink in those days.

Mike Hecht: It was invented in Lowell, Massachusetts, just down the street from us. It is even now the state drink of the great State of Maine, just to our North. And embedded in the acronym is another acronym ISRU, In-situ Resource Utilization, which frankly, Mat, means living off the land. But as I like to say, they couldn't use the acronym LOL it's already been taken.

Mat Kaplan: Right. As I'm doing now.

Mike Hecht: Embedding an acronym is not normally something I like to do, but the first attempt to do this came on a mission that never was, the 2001 Surveyor Lander. It was in its final steps of development when we lost the Polar Lander in 2000, late 1999. It was put on hold and never really flown. Although it did have a resurrection with Phoenix, the Phoenix Mission. But on the 2001 Lander was an attempt to do a much smaller, more modern version of what MOXIE became. And that was called MIP, which was the Mars ISPP precursor. ISPP was what they used to call ISRU. It was In-Situ Propellant Production.

Mike Hecht: So, that had an embedded acronym in it. And I thought that's the one thing on Mars on the 2001 Lander that never found another ride to Mars. And so, it's a little bit of a very subtle homage to people on the inside to say, "We're going to embed that same acronym in the middle of MOXIE as a little bit of an homage to the folks who developed the MIP project. It's a long story.

Mat Kaplan: Yeah. But MOXIE is a little bit of a Phoenix in itself it sounds like.

Mike Hecht: Indeed. Indeed it is. And I've always been of the impression that if you propose and are selected to fly an experiment to Mars or elsewhere, NASA will eventually find a way to do it. And I don't know if it's a conscious policy or just the way it works out, but it seems that all the projects I've been involved in over the years, that for one reason or another, like the 2001 mission haven't made it, eventually find another one.

Mat Kaplan: All right. Well, let's talk about what it does. I think I've heard you say, and others say, and you can see pictures of it. We'll put up the link to the MOXIE website on this week's show page at with lots of other resources. It is only about the size of a car battery. How much O2 are you going to get out of this little bit?

Mike Hecht: That is the key question, Mat. And we're limited not by what we could build. We could build a full-size MOXIE unit today, probably as easy or easier than the effort to build this small one. But we have two serious constraints. One constraint is that we're on a Rover that's only so big. And we share it with seven other instruments.

Mike Hecht: The other constraint that's even more significant is this Rover, this big Rover, the size of a mini-cooper, right? Runs off of hundred Watts, 110 Watts. Back in the day when we had incandescent light bulbs, a light bulb on your desk lamp would have been brighter than, more power than that.

Mike Hecht: It's a very, very puny power system. To do what we want to do on Mars to support human exploration, we'll take 25, 30 kilowatts. So, just to run on the small power supply power system, we had to scale way, way back.

Mike Hecht: Nonetheless, we can demonstrate all the principles, all the technology, all the hardware on a small scale. And so, MOXIE will produce about 10 grams an hour of oxygen. Now, if you and I were sitting having this conversation on my, or in fact sitting and having this conversation today, we're probably consuming about 20 grams an hour, about twice what MOXIE will produce. It's about the amount that if I look out my window at the trees, that a modest size tree in my yard will also produce about 10 grams an hour of oxygen from the CO2 in our atmosphere.

Mat Kaplan: I thought that humans needed a lot more O2 per hour. And so, a couple of these little boxes would be able to keep me alive on Mars. Apparently, if it performs as well as you hope it will.

Mike Hecht: Well, absolutely. Keeping humans alive is easy. And that's really not the main purpose of the MOXIE technology. The common link though, to the main purpose is that we as human beings use fuel. Okay. We use fuel. We call it food. But if we weren't appreciating it aesthetically, we call it fuel. And to burn fuel requires oxygen or something like oxygen, whether you're a human being, whether you're a fireplace, whether you're an automobile, or in this case whether you're a rocket ship.

Mike Hecht: And the more fuel that something uses, the bigger it is, the more oxygen it needs. The thing that we do not appreciate on earth is that this oxygen that we are burning, that our car is burning when we drive, weighs much, much more than the fuel. Fuel is light. It's based on hydrogen. It's very light stuff.

Mike Hecht: And so, if we had to carry an oxygen tank in our cars, because we couldn't get oxygen for free in the air around us, it would weigh maybe four times what the gasoline weighs. So, if we're thinking what we need to bring to Mars and what it weighs, the single heaviest thing we would need to bring is a tank of oxygen, not for the astronauts, that would be a little tank, but for this rocket that is going to take our crew from the surface of Mars back up into space, lift it off the ground, climb out of the gravity well, of Mars, that uses a tremendous amount of fuel. And of course it needs to breathe a tremendous amount of oxygen.

Mike Hecht: So really, a customer from MOXIE is primarily that ascent vehicle, that Mars ascent vehicle, that rocket, that will return our crew to Mars orbit as the first leg and their return journey and which I think so many of us read about and saw in the movies in Andy Weir's, The Martian.

Mat Kaplan: You know, I was going to bring Andy up. I'll save that for a moment. But it sounds like, therefore making the stuff that we need to breathe may just be a side benefit of what will someday be a fairly big plan to create this oxygen that will be used as the oxidizer in those rockets when we want to come home.

Mike Hecht: Yeah. It will definitely be a side benefit. One reason why it's a side benefit is the astronauts can't wait until they get to Mars to have oxygen to breathe, right? They have to bring it with them just to get to Mars in one piece and healthy and hale and hearty while the ascent vehicle can wait. It doesn't need that oxygen until it's time to leave.

Mat Kaplan: Have you ever talked with Andy Weir, the author of The Martian?

Mike Hecht: Not substantively. I've emailed to him. I may have had one conversation verbally, but haven't gotten to know him. No.

Mat Kaplan: I was curious because when he first came on our show, he's been on a few times, he talked about that big oxygen generator inside the habitat that played a pretty major part in the book and the movie. I'm just wondering, when you saw the movie, you must have been intrigued. He told us that he had based it on the research he'd done at the time, but later learned it could have been a simpler and significantly safer device. Was that right?

Mike Hecht: Well, first of all, before I saw the movie, I had read the book about three times.

Mat Kaplan: Oh, yeah. Me too.

Mike Hecht: And I've always said I'm indebted to him for making it so easy to explain to people what MOXIE does. I just say the word oxygenator and they say, "Oh, I get it. I know how it works." As for safer, he didn't say a lot about the technology that the oxygenator was using. So that's not something I gave a lot of thought to. Of course, Mark Watney did some things it wasn't designed for that were a lot more dangerous. And he was dealing with hydrogen and explosive constituents.

Mike Hecht: There are different ways you could do the oxygen generation. There are some that are, I think, arguably much better and simpler than the way MOXIE is doing it, but just not ready to go, not ready for prime time. So, it may well be in the future that the solid oxide technology we're using for MOXIE is overtaken by, say, a what's called a proton exchange membrane technology, which is what's used mass produced for hydrogen fuel cells. Because basically the technology for MOXIE is the same as a fuel cell. We just run it in the other direction to make an electrolysis system.

Mat Kaplan: I'll be back with MOXIE principal investigator, Mike Hecht after a break. Still ahead is our discussion of the Event Horizon Telescope.

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Mat Kaplan: Can you say a little bit more about how MOXIE achieves this?

Mike Hecht: Absolutely. Absolutely. The trick of course, is that you have on Mars, very little atmosphere, but it's all CO2. So, when you total it all up, if you were to take a box full of air on Mars and a box full of air on earth of the same size, the box full of air in Mars would have 20 or 25 times as much CO2 in it, but very little else.

Mike Hecht: So, you've got a lot of CO2 to work with. And the question then is, how do you turn CO2 into O2? Well, you don't have to be a chemistry major to understand from that, that it's already in there. You have to separate some oxygen from the CO2 molecule, which has one carbon, that's the C, and two oxygen atoms, that's the O2.

Mike Hecht: There are two ways you could do this that you can imagine. One way is to just pull off the carbon and be left with the O2. And that's not the way we do it. The other way is to pull off one of the oxygen atoms and be left with oxygen and C-O, which is what we call carbon monoxide. And I think most people are familiar with that because you go and buy a little carbon monoxide detector to put next to your furnace in the basement.

Mike Hecht: It's nasty stuff if you breathe it, but it's also a gas. So, given those two choices of making carbon, which is candles that are making carbon monoxide, which is a gas as the by-product, carbon monoxide wins hands down. And so, a lot of the technical difficulty with MOXIE is just plucking off one oxygen atom without inadvertently plucking off two. Okay?

Mike Hecht: So, that's the chemistry of how it works. And why do I say it's like a fuel cell? Well, imagine the fuel cell reaction. What you do in a fuel cell, most people are familiar with hydrogen fuel cells where you put hydrogen in, you put oxygen in, you get out H2O, which is the stable molecule, the stable form, and you get out electricity.

Mike Hecht: If you did the same thing with a carbon-based system, you'd put in CO, carbon monoxide, you'd put in oxygen and you'd get out CO2, a nice, stable molecule and electricity. That would be the fuel cell. Now, if you say you're going to run that backwards, and literally that involves reversing the voltage, putting a negative instead of a positive voltage on. If you run it backwards, you start with electricity, you start with CO2 and you get out C-O and oxygen. That's how we do it. And that's, again, why you could convert it to a fuel cell easily or with the same technology.

Mike Hecht: And it does it by a combination of, well, a very subtle combination of techniques. The first of which actually pull off this oxygen ion since it's just one, then the real heart of it is the membrane that, under an applied voltage, pulls that oxygen ion into a separate channel, a separate compartment, without pulling anything else across. And that involves a very specialized ceramic heated to 800 degrees centigrade with a highly controlled voltage across it. And the current that flows in the circuit is identical to the oxygen current. Oxygen ions produce a current, their charge and oxygen current flowing the other way.

Mike Hecht: And that's the circuit you make. You have electrons flowing one way as electricity, oxygen ions flowing through the membrane in the other direction. That's the product that you're making. Then turn it around, you get a fuel cell.

Mat Kaplan: Fascinating technology. I mean, and when you talk about this needing to be heated to 800 degrees, you start to understand the energy consumption that you were talking about. I saw that MOXIE needs about 300 Watts to do its work. Is that correct? And where do you get that? I mean, that's a huge part of the Perseverance energy budget.

Mike Hecht: Yes, Mat, that's absolutely right. And this is why MOXIE will not run very often on Mars. The expectation, or the arrangement, if you will, with NASA is that we are scheduled in to run 10 times in the primary mission, which is one Martian year, so about two earth years. So, in other words, every couple of earth months that we'd be expected to run.

Mike Hecht: Now, in practice, when you plan these missions, of course, there are always opportunities that you take and you seize. And I'd be surprised if we didn't run more often than that, but that's the primary reason, when MOXIE runs, everybody else stands down and steps back and waits and gets out of the way, or are takes a rare vacation day. And an important thing to understand about how these Mars surface missions work is I have a wimpy power supply, whether it's solar or whether it's the radio isotope version that Perseverance uses, they're pretty wimpy.

Mike Hecht: And so, you never actually run off of the solar panels or run off of the radio isotopes source. You run off of a battery. And the battery charges up all night long. That's really why they don't like to run these things at night. That's the best time for charging a battery. And then when you're ready to go, you just drain the battery as fast as you need to. So, MOXIE is designed to use the whole day's worth of available energy. I say available because the Rover needs some, but everything else the Rover isn't using, MOXIE is using.

Mike Hecht: So, when we're all done, we leave the battery the same way we found it. We use a whole day's worth of charge. We bring the battery down to where it was when they started charging it up and you're ready to go the next day as if nothing happened. So, we're energy-neutral. The only thing we impose on our shipmates is a day off. Then we run.

Mat Kaplan: Probably a well-earned day off.

Mike Hecht: Oh, certainly a welcomed day off. I can tell you that.

Mat Kaplan: How will you know that it's working? That it's creating the oxygen you hope to create?

Mike Hecht: This was a source of, I'd say creative tension all during the development of MOXIE. The first sentence I believe, or the first paragraph in our proposal said, "We're not just flying MOXIE to Mars to see if it works. We're flying it to Mars to learn how it works." And we put all emphasis in the proposal on sensor systems on really transparent ways to diagnose everything that's going on.

Mike Hecht: Now, you get down to then reality, you get down to the pragmatics, the nuts and bolts of developing a system like this that is so, so immature when you start and you're quickly overtaken by just the need to make it work. Okay? So, the sensor systems are maybe not all we hoped for, but they're adequate, they're adequate. And we will learn, we'll be able to follow the gas as it flows through the system to know its pressure, to know its temperature, to know its composition, we'll know the temperature everywhere in the system. We'll measure these currents that are flowing through it. We'll measure the voltages flowing through it.

Mike Hecht: A big part of MOXIE that I did not describe, and a major consumer of power, that 300 Watts you mentioned is actually what we call the compressor. And it is, it's like any other compressor you might buy to pump up your tires. It's a scroll pump compressor. It uses a lot of energy, but the Martian atmosphere is very thin. And you can't just sit and wait for it to come to you, you have to pull it in. You have to suck it in and collect it. And we actually pressurize it as we do that. That's a key part of that energy equation as well.

Mat Kaplan: Fascinating again. This reminds me of something else I heard you say. When you were talking to the Mars Society Conference a few years ago, you said that vacuum is a scarce resource, which is a pretty entertaining statement in itself, but what did you mean by that?

Mike Hecht: I think the point I was making at the time was that the in-situ resource utilization is maybe not even the right word for what we're doing. And I was suggesting that we should be talking about in-situ resource transformation as the special thing that MOXIE and all the other ways of excavating and using resources accomplish. And whether it's making cement out of Martian soil or growing plants on Mars, that's all a transformation of resource. It's utilization.

Mike Hecht: We utilize resources, every time we use a parachute on Mars, right? We're utilizing the atmosphere. We're utilizing resources whenever we deploy a solar panel and collect sunlight. And the point was that on earth, I spent a good part of my career doing surface science, science of materials in vacuum systems and working very, very hard to find places in chambers on earth that didn't have any air in it. That's a very hard job, right?

Mike Hecht: So, one of the things that was done in The Space Shuttle program was to build a wake shield for the shuttlebay, because it turns out even on the shuttle generates so much outcasts that the vacuum around the shuttle by itself is actually fairly contaminated with molecules and atoms and particles coming from the shuttle itself.

Mike Hecht: So, they've developed a big umbrella that they drag behind them. So, the area behind the umbrella is really a good vacuum and that could be used for vacuum manufacturing. It's a scarce resource on earth, and to say it's plentiful in space is an understatement.

Mat Kaplan: Talk about getting something from nothing.

Mike Hecht: Absolutely.

Mat Kaplan: I did not know that about the shuttle. Here's something else that only just occurred to me. Where is the oxygen going to go of the stuff that you create? You just release it or what happens?

Mike Hecht: Yeah. So, unfortunately we just release it. One thing we had hoped to be able to do and NASA correctly said, "Don't try to do too much guys. This is going to be hard enough as it is." But we actually wanted to reuse it. As I mentioned earlier that MOXIE could be converted to a fuel cell. And the original plan was to store a certain amount of the oxygen, then turn MOXIE the other way and turn it back into CO2 and recapture some of the energy it had burned just to show that we could, in fact, use this stuff as a fuel and burn it. I'm using burn colloquially in this case, burn it in a fuel cell to make energy.

Mike Hecht: In the end we said, "All right, this is not what we're focusing on right now, where focusing on making it." So, we measure it and make sure it's pure. And it's a catch and release, if you will. Release it back into the atmosphere where it gets diluted. There is a tiny bit of oxygen in the Martian atmosphere as it is. A 10th of a percent. The oxygen we produce pretty quickly gets diluted back into that background.

Mike Hecht: The CEO we produce pretty quickly finds oxygen atoms to combine with and turns back into CO2. And so, we will not leave any footprint on Mars, but we're not utilizing it either.

Mat Kaplan: Like all good campers.

Mike Hecht: Like all good campers, that's right. Well, I wish we could say we're packing it in and packing it out, but that we'll have to wait.

Mat Kaplan: It sounds like there's plenty of room for MOXIE Mark II.

Mike Hecht: Oh, absolutely. So MOXIE Mark II the idea follows what's been written about how we should send people to Mars since back in the Wernher von Braun days in the early day of the Space Program. People thought about this really seriously. I mentioned earlier that we have an opportunity once every cycle of Mars orbit.

Mike Hecht: So, all the plans have been designed around that 26 month cycle, forever. And it's been a long time. I can't remember the last time that someone wasn't sending something to Mars and that opportunity. Boy, I mean, this year we've got United Arab Emirates going. There's been a lot of people taking advantage of that 26 month cycle.

Mike Hecht: The idea then is that before you send people, it would be really helpful to have everything in place that they need. I sometimes joke you want to have your Airbnb all set up and waiting for them so they just have to travel with a toothbrush. And so, that's the idea. Among these things you send early is you send an ISRU plant, you send a big MOXIE, right? That gets there in seven months or so, the crew doesn't take off for another 18 months or so, 18 or 19 months.

Mike Hecht: So you spend the next 12, 14 months filling up the oxygen tank for the ascent vehicle. And then you say, we're done. It's ready to go. And it's okay to launch the crew. That's the synopsis of the strategy of how you do this.

Mat Kaplan: I was in the room, I like to say, I've said to Bob Zubrin, when he first presented many years ago now the Mars Express concept and got a standing ovation after he had finished. And it has evolved over the years. And this kind of thinking, this approach that you've just described, this is something that Zubrin had in mind from the start. Isn't it?

Mike Hecht: Well, not just Zubrin. That goes all the way back to Wernher von Braun. It's a colleague of mine, Don Rapp, who's written a number of books on the subject, and he's a key member of the MOXIE team in his eighties. We should all have such a productive retirement as Don has had. I think he's published seven books since he retired.

Mike Hecht: Don actually started accumulating plans that people have put together for Mars, for how to send people to Mars. And he counts it to a thousand before he gave up. And he says the vast majority of them, the vast majority of them, not all of them, take this approach of saying, you spread it over two cycles.

Mike Hecht: Ideally you sustain it over many cycles. So, when you send the crew, as Andy Weir described, you also establish the infrastructure for the next crew. So, of course, the Mark Watney journey is to travel from his landing site to the site that was already being prepared for the next crew where there was an alternate ascent vehicle. That's what that's about.

Mat Kaplan: I think a lot of what you have talked about over the last few minutes demonstrates something else I've heard you say. But I wonder if you could maybe give us another example of what you're talking about. When you say that we need to think like Martians.

Mike Hecht: Yes. The hardest thing in the world to do is to think like a Martian. This is what fascinates me about the study of Mars, the planetary science part of it, because it makes you aware of just how much we take for granted. Just how much is wired in about the way we interact with the universe. And when you go to a place that's even subtly different, where a ground rules change, where you have blue clouds and a pink sky, you realize just how much of a foundation your world experience is imposed on what we see as objective science.

Mike Hecht: It causes you to rethink so many things. I love that experience. A simple example I love to give has to do with temperature. Of course, everyone talks about temperature. It's too cold in this room. It's too warm in this room. I feel a draft. And that is a deeply ingrained concept that is relevant only in places like earth that have an atmosphere that's so thick. To a Martian, we'd look like fish swimming in an ocean.

Mike Hecht: We are walking around in such a thick atmosphere, and it is so thick that, in fact, when the atmosphere is cold, we get cold. And when the atmosphere is warm, we get warm. And that is a unique characteristic of this kind of thick atmosphere. And even today, I constantly hear engineering saying, "Oh, we shouldn't send humans to the poles because it's too cold," or go to this other place where it's too warm.

Mike Hecht: And I have to stop them and say, "Now, wait a minute. Wait a minute." When you think about the atmosphere you're talking about, and talk to an astronaut, like my colleague, Jeff Hoffman who's the deputy PI for MOXIE and has flown in the shuttle five times. You get into space, you're hot. Now, is space hot? Is space cold? Well, neither.

Mike Hecht: And the reason that it's neither is because we use temperature as a proxy for heat, because on earth, in this thick suit you can use temperature as a proxy for heat. If you're in space, you're hot if the sun is shining on you, you're cold if you're in the shadow of the vehicle, and at the same time you're in this vacuum bottle and you're generating body heat. And that's going to make you hot most of the time.

Mike Hecht: So, temperature is not this characteristic of the environment, right? Temperature is a characteristic of you or of your instrument. And really the characteristic of the environment is all the heat that's flowing in and out and radiating, and convecting and conducting. That's what's characteristic of the environment.

Mike Hecht: So, when I say think like a Martian, and I wrote a little science fiction story about this a long time ago, when I say think like a Martian, what I mean is start off by imagine that you lived on Mars, and what would change, and what would be different about your experience of the world? And then ask how you apply that to the instruments or the systems or the processes you're building. And you'll encounter some surprises if you do that.

Mat Kaplan: That example you gave is exactly the one that I was hoping that you would, Mike. We have spent a lot of time now talking about the red planet. In our last few moments, I want to turn to what easily could be an entire different life for anybody working in the sciences. And that is this other title that you have, deputy project director for the Event Horizon Telescope, that made such big news when you and your team released that first ever image of a black hole, or at least what was happening, what was going on around that particular black hole.

Mat Kaplan: So, congratulations as well on that magnificent effort, that tremendous success. I really wonder if there has ever been any kind of collaborative achievement in science that equaled it?

Mike Hecht: I think you would have to look at, for example, the high energy physics world, and some of the particle physics discoveries, or in the astrophysics world, it's something like the LIGO and the extraordinary detections of black hole collisions by LIGO that was the result of years of effort of many, many people.

Mike Hecht: It's an extraordinary testimony for who we are as people. And honestly, the missions that we mount to Mars. If you think of the number of people involved that actually probably dwarfs the Event Horizon Telescope. I have been just extraordinarily fortunate, I don't know how else to describe that, to have opportunity on working on two such audacious projects in a short span of time. There's the Perseverance mission to Mars, talk about audacity and then The Event Horizon Telescope doing something that Einstein was sure was not possible. And many people have been sure is not possible. And being able to actually image something that is nearly inconceivable to our brains.

Mike Hecht: When I talk about thinking like a Martian, a picture of a black hole causes you to think like someone outside of our universe, I suppose. To some extent, I was given this opportunity because the two types of adventures have a lot in common, to try to achieve extraordinary scientific results that requires tremendous coordination of infrastructure.

Mike Hecht: In the space mission world, it's everything from the people who build the tanks for the rockets to the software people, the software experts programming the operations of the instrument. And then of course, to people like you, who are letting the world know what we're doing, it's an extraordinary communal exercise of hundreds of thousands of people.

Mike Hecht: And to do what the Event Horizon Telescope has done and to coordinate so many facilities and installations around the world to all look at the same thing with the same equipment at the same time synchronized to picoseconds is extraordinary. And the fact that I had been involved with the Mars Missions was my entree into becoming involved with the Event Horizon Telescope.

Mike Hecht: "Hey, you know how to organize this sort of big enterprise, come help us." And I was able to apply a lot of what I had learned about actually project management, as it turned out, for large scientific enterprises to the Event Horizon Telescope. And that was my entree as someone who had straddled three worlds, who had straddled the engineering world, the science world, and the project management world, which are three different disciplines. And they turn out to be an extraordinarily powerful combination in just this sort of enterprise.

Mat Kaplan: Yeah, I can sure see the connection. But it remains maybe the most interesting juxtaposition of professional duties of anybody that I've talked to perhaps on this show. And that's 18 years worth of guests. Let me leave you with this. What is the EHT up to now?

Mike Hecht: Well, the EHT is, first of all, has a big piece of unfinished business. Everybody expected back in April of 2019 to see a picture of Sagittarius A. And Sagittarius A is the black hole, the super massive black hole millions of solar masses in the middle of our galaxy of the Milky Way. That's what everyone expected to see.

Mike Hecht: What we showed them was not Sagittarius A* it was a black hole that should be called M87*. We just tend to call it M87. There was a Hawaiian name given to it a year ago Powehi. That is another galaxy, not terribly far away as galaxies go, but galaxies are pretty darn far apart. And it turns out, although that would be ordinarily a thousand times fainter, it's also a thousand times larger, so it's brighter to begin with.

Mike Hecht: And so, it's about as easy to see as Sagittarius A* from the earth in that respect. And it also, because it's so large, now and this is a relativistic issue, things can only change as fast as it takes in the amount of time it takes light to go across it. So when something is as large as billions of solar masses like M87, it changes slowly.

Mike Hecht: Where Sagittarius A*, being a smaller, only millions of solar masses, a smaller source, changes rapidly. And that makes it that much hard to get it to sit still for a picture. It's a squirmy toddler you're trying to take a picture of. And it's been hard. So we've been working on that and working on that and working on that. It's close. That's going to happen. I can't tell you when, I can't tell you exactly what will be in it.

Mike Hecht: So, that's one piece of unfinished business. And of course, we're still trying to take data every year and have new campaigns. One of the things that drives the schedule of the Event Horizon Telescope is there's really only one time a year in March, April, where you get the confluence of circumstances where the sources are visible in the sky, because they move around the sky like any other sky object. And the weather is acceptable at the different telescopes. There's only that one window every year that allows us to see.

Mike Hecht: This year, we couldn't observe because the critical telescopes were shut down because of the pandemic. Last year, there were other circumstances that kept us from observing that, a combination of weather and some telescope maintenance issues, and the year before, 2018, we were somewhat, I won't say crippled, but the observation was compromised by something as non-natural as gang activity around the large millimeter telescope in Mexico. There was armed gangs involved in piracy of gas mines, gas pipelines, and they couldn't get the crews to the telescope.

Mike Hecht: So, we have to fight everything from pandemics, to gangs, to bad weather, just to get an opportunity to observe each year. But we're at the same time building up capability. The next time we observe, we hope to observe in 2021 if all goes well. That we'll have more and more fidelity, more and more data. So, the next big thing I think will be movies of Sagittarius A* someday.

Mat Kaplan: Wow.

Mike Hecht: That's what we'd love to see.

Mat Kaplan: Oh, I can't wait to catch that film.

Mike Hecht: That will be extraordinary.

Mat Kaplan: Mike, you have given us at least two very good reasons to invite you back. Here's to a great, successful landing on Mars in February, and to clear skies, one might say, representative of all the other factors you have to deal with to make the EHT do what it's capable of doing. Sounds like we very much might have more to talk about. I hope you'll come back to the show.

Mike Hecht: Mat, I would really look forward to it. And I just want to say also, the U.S government, other governments, don't give us all this money. Don't give us, in the case of Mars, 2020, a billion and a half dollars, or a billion dollars just to do something that will impress our fellow geologists and planetary scientists at professional meetings. They do that because the entire world looks to what we do for inspiration, for illumination, for a sense that we are extending the human experience where it's never gone before.

Mike Hecht: And it's folks like you and shows like this that actually fulfill that mission. We're just the guys who do the work. You're the guys who actually deliver the work to the people who are paying for it and who are receiving it and who are gaining from it. So, thank you for that. Thank you and all your colleagues for doing what you do.

Mat Kaplan: You are very welcome, Mike. Thank you for those kind comments. And that's why we do the show because, it's certainly why I do it, because it is a thrill to be able to talk to folks like you, leading teams that are doing this work that is expanding what we know of life, the universe, and everything. Mike, keep up the great work. And I look forward to talking again.

Mike Hecht: Thanks so much, Mat. So do I.

Mat Kaplan: Mike Hecht of MIT is the MOXIE principal investigator and deputy project director for the Event Horizon Telescope collaboration. Mars ahead when we join Bruce Betts for What's Up?

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Mat Kaplan: Time for What's Up on Planetary Radio. So, we are joined by Bruce Betts, the chief scientist of the Planetary Society. Who's here with me every week to talk about what's up in the night sky and much, much more fun contest answers this time around. Hi, welcome.

Bruce Betts: Hello. I'm excited, Mat.

Mat Kaplan: Were you excited a couple of nights ago, as we speak to, did you get to see the Geminids?

Bruce Betts: I got to see some clouds. They were lovely.

Mat Kaplan: Me too.

Bruce Betts: I looked a little bit last night after the peak because it was clear. I didn't get to see that. How about you?

Mat Kaplan: No, no. I only checked, we were up in the mountains, nice, dark sky, new moon as you've told us there would be because that you know. And no, it was clouded over. It was overcast. So, no luck. I don't know. I didn't get up again at 2:00 AM to check either. So, all right, what else is up there that we may or may not be able to see?

Bruce Betts: Jupiter and Saturn, it's all about Jupiter and Saturn for the next couple of weeks. You can ignore the rest of the sky, it's not important right now. Well, I mean, it's still fun, but Jupiter and Saturn will be closer on December 21st than they have been in almost 400 years as they appear in our sky. There'll be about six or seven earth minutes. So, about a 10th of a degree apart. And that is the equivalent of being closer than a quarter of the moon's diameter.

Bruce Betts: You should be able to resolve them still separated with a decent eyesight. There'll be looking really cool. The challenge will be their low, as you pointed out on a previous show, Mat, they're already low in the West not long after sunset. So you'll want a pretty clear view to the West. And if you have clouds the night of the 21st, take heart, they're almost as close on the 20th and the 22nd. So look in the evening.

Bruce Betts: West Jupiter, of course, is the really bright object looking like a really bright star, Saturn looking like a yellow star. They should be in the same field of view for binoculars or most home telescopes, unless you get to a bigger telescope. So, it's going to be groovy watching them get closer together, coming up on the 21st and getting farther apart after that. We've got an article coming up on our website with more information at Did you have any further thoughts upon this, man?

Mat Kaplan: Well, you did get this text message came in moments ago from Mars, "Regarding comment, ignore rest of sky. What am I? Chopped regolith?"

Bruce Betts: Okay. Several questions come to mind. Strangely the first to pop into my head was not why Mars was contacting us, but how it got around the light speed limit on communication. And I didn't know Mars could listen to the show early when we're recording.

Mat Kaplan: [crosstalk 00:49:53] make it available.

Bruce Betts: Checkout bright Mars, still bright in the South when you're done looking at Jupiter and Saturn, or if you're an aerial file, just go ahead and check out Mars first and then Jupiter and Saturn. You know, Mars, you are far more than chopped regolith to me.

Mat Kaplan: Wait, there's another text coming in. Oh, it's a red smiley face. I think we're good.

Bruce Betts: Oh. And before anyone gets angry, Venus predawn is, sorry. And there's stars. There's so many stars. But Jupiter and Saturn doing something special. That's all I'm saying. Mars is of course always special and near and dear to my heart.

Mat Kaplan: I think we're good.

Bruce Betts: Onto this week in Space History, it was 1968 that Apollo 8 launched and sent the first humans around the moon.

Mat Kaplan: Yeah.

Bruce Betts: We move on to Random Space Fact.

Mat Kaplan: A little trill, I like it.

Bruce Betts: Almost all Mars landers, and perhaps somewhat coincidentally, all successful Mars landers have been targeted to land northwards of about 15 degrees South on Mars. That's because Mars has this general topographic dichotomy with Highlands in the South and lowlands in the North, at least on average.

Bruce Betts: With Mars's atmosphere already really thin, landers need to get all the atmosphere they can get to slow down and hence the targeting of lower elevations. We move on to the trivia contest and I asked you how many aluminum panels are or were in the Arecibo radio dish? How did we do?

Mat Kaplan: A great response to this. I don't know if it's because everybody wants to proudly wear that new planetary society cap, which we will once again be giving away this week or if they just, it was in honor of Arecibo. Here is the answer. Hidden away in this week's submission from our Poet Laureate, Dave Fairchild.

Mat Kaplan: Down in a sinkhole, they built Arecibo at 305 meters wide. Inverted dome in its green island home with thousands of pebbles inside made of aluminum, I'd say, by rule of thumb. Seven by three feet across. 38,7 and 7,8 rectangles make this great telescope boss. Easier to understand? How about from Matt Kotter in Missouri. 38,778 panels and one born villain. They got the number, right?

Bruce Betts: They did. They did indeed. That's a lot of panels.

Mat Kaplan: Chris Mills in Virginia. He had the same number. It took a while to count them though from the aerial photo. I hope I didn't miss one.

Bruce Betts: Wow. I mean, they were good on you.

Mat Kaplan: In Illinois is Henry Anderson who gave us the answer in Spanish, which I will not read because it would be an insult to all of our Spanish speaking listeners to hear me attempt that. We love it when we get unique units of measure. From John Burley, total square footage of 814,338 square feet, or big enough to fit 101.8 planetary society headquarters.

Bruce Betts: Wow.

Mat Kaplan: That's impressive. Isn't it?

Bruce Betts: It fit 101, but I didn't know about the extra 0.8. that's cool.

Mat Kaplan: That's what makes the difference, that 0.8. Here's our winner. Sorry to keep stringing you along, Corey Schmidt, first time winner in Missouri. They are (were) sigh 38,778 panels. They replaced the original wire mesh that was installed in 1963 when the dish opened. And then he added this. I luckily got a chance to visit the observatory a few years back while living in Puerto Rico and still have fond memories of my visit. I bought a commemorative pint glass as a souvenir. And from now on, every beer I drink from it will be bitter sweet. Corey, congratulations. Nice message. And we hope this sweetens the memory a little bit.

Mat Kaplan: Maya [Soukup 00:53:56] in Newfoundland, Canada, as a geo-scientist, learning from your podcast that the dish was built into an extended limestone valley, that's something that Bill Nye mentioned, and that the contents were then used to construct support materials was very interesting. I wonder if they'll need geologists to find the next site. Are you volunteering Maya?

Mat Kaplan: Just a couple more here. "Fingers crossed," says Darren Richie. For a good Starship test today. He wrote this a few days ago. With that kind of payload capacity, perhaps an Arecibo 2 on the lunar far side would become feasible, would be a worthy successor. I don't know. What do you think?

Bruce Betts: I think it would be incredibly challenging and expensive.

Mat Kaplan: It would be.

Bruce Betts: I mean, cool results, but economically and feasibility challenged.

Mat Kaplan: Probably not a lot of profit in it either for SpaceX. Finally this from Jean Lewin in Washington. A loss to all, though not all know the impact of this tragic blow. A limestone cradle, a karst was home to this Gregorian inverted dome. This void created by nature's wrath impedes our travel, but not our path. Rebuild this wonder. Return our site, reveal the mysteries of distant light. I'm going to send that one to a Francisco Cordova, I think, the director of Arecibo.

Bruce Betts: Yeah, that's nice.

Mat Kaplan: That's it. A lot of stuff there. So I guess we better move on.

Bruce Betts: Returning to Martian typography, in what feature is the lowest point on Mars? Go to

Mat Kaplan: Oh, wait. I got another text here. It's Mars again. All is forgiven.

Bruce Betts: Aww.

Mat Kaplan: You have this time until Wednesday, that'd be Wednesday, December 23rd at 8:00 AM Pacific Time. Your prize, should you get it right and be chosen is going to be that Planetary Society baseball cap, which is now being featured at or just go to And you can check out all our other merch as well. I think we're done.

Bruce Betts: All right, everybody. Go out there, look up the night sky and thinking about using light waves to look at ocean waves, making sound waves that you hear. Thank you. And goodnight.

Mat Kaplan: Okay. I got to ask. Is this happening?

Bruce Betts: Only in my mind?

Mat Kaplan: It sounds brilliant though. That maybe some new earth-observing satellite from NASA. All right. Well, they owe you if they turn this into music. That's Bruce Betts, the Chief Scientist of the Planetary Society who joins us every week here for What's Up.

Mat Kaplan: Planetary Radio is produced by the Planetary Society in Pasadena, California. And it's made possible by its oxygen-loving members. I promise you that joining them at will be a breath of fresh air. Mark Hilverda is our associate producer. Josh Doyle composed our theme, which is arranged and performed by Peter Schlosser. Ad astra.