Planetary Radio • Mar 10, 2021

InSight’s Mole: A Martian Science Odyssey

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Troy Hudson

Troy Hudson is a Planetary Geologist and Instrument Engineer for Jet Propulsion Laboratory

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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

Troy Hudson and a brilliant international team created a device that would hammer its way below the surface of Mars. Mars had other ideas. The Jet Propulsion Lab engineer and scientist returns to tell us the heroic tale of the InSight lander’s Heat Flow and Physical Properties Package, also known as the mole. Stay with us for a tour of the current night sky and a new space trivia contest from Bruce Betts.

Troy Hudson and InSight
Troy Hudson and InSight Painting by Matthew Cogswell of Troy Hudson celebrating the landing of InSight on Mars.Image: Matthew Cogswell
InSight self-portrait
InSight self-portrait InSight used its robotic arm to capture the images used for this panorama of its landing site on Dec. 7 and 11, 2018. You can explore the full-size image in virtual reality here.Image: NASA/JPL-Caltech/Andrew Bodrov
Top of the InSight Mole Exposed, Sol 209
Top of the InSight Mole Exposed, Sol 209 On sol 209 (29 June 2019), InSight used its grapple to pick up the heat probe instrument's housing, exposing the unburied "mole" inside a surprisingly large hole.Image: NASA / JPL-Caltech

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What was the original official name of the Mars InSight mission?

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Of the spacecraft which used Venus for a gravity assist maneuver, which went farthest out in the solar system?


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How many uncrewed spaceflights have there been to the International Space Station?


136 uncrewed spaceflights have launched toward the International Space Station, or at least to where it would be. 6 of them didn’t make it.


Mat Kaplan: The Tale of the Mole: A Martian Science Odyssey, 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. Today, a story that is heartbreaking, heroic and inspiring, brought to us by Troy Hudson of NASA's Jet Propulsion Lab. Troy was with us when the InSight Mars lander reached the red planet, and we had every reason to believe he'd return to celebrate the success of the Heat Flow and Physical Properties Package or HP cubed instrument, more fondly known as the mole.

Mat Kaplan: Space is hard and Mars is harder, but lessons have been learned. Troy will also tell us about the exciting projects keeping him busy since work with the mole ended. It wasn't designed to do this, but the Parker Solar Probe has somehow peered through the thick clouds surrounding Venus to reveal some murky surface features below. That's the space snapshot that leads this week's edition of the Downlink, the Planetary Society's free newsletter.

Mat Kaplan: Just below that image are these space headlines. October of this year will be a busy month for space exploration. The Lucy Mission will launch toward Jupiter and six Trojan asteroids that share the big world's orbit. And the James Webb Space Telescope has passed more tests on the way to its October departure. I bet a lot of you watched the triumphant March 3rd flight and vertical landing of yet another SpaceX spaceship. I bet you also saw the rocket blown right off the pad minutes later in an unplanned disassembly event, still pretty impressive.

Mat Kaplan: SpaceX has the next iteration almost ready for primetime. The Downlink Wow of the Week this week is a 1975 Kitt Peak image of the Pleiades, that most famous of star clusters. It's worth a look and you'll find it Dr. Troy Hudson got his PhD in geological and Planetary Sciences at Caltech, and it's Caltech that runs the nearby Jet Propulsion Laboratory for NASA, where Troy works as a technologist and instrument systems engineer.

Mat Kaplan: Born in Houston, Texas, Troy has spent the last few years working as a liaison and team member with scientists and engineers at the German Aerospace Center, developing HP cubed, also known as the mole. It's why he was on stage with us when this happened on the 26th of November, 2018.

Speaker 2: Touchdown confirmed.

Speaker 3: Wow. Yes.

Mat Kaplan: That was the celebration at Caltech's Beckman Auditorium of the InSight lander's successful touchdown on Mars. Then the work began, soon after, followed by the troubles. Troy and the HP cube team worked tirelessly and brilliantly for two years to get the mole on to the surface of Mars. Their effort did not end with success. Yet the story that you're about to hear from Troy demonstrates that their long endeavor was not in vain, not in the least. Troy, welcome back to Planetary Radio, I am very happy to have you back on as a guest, and to congratulate you on all the work that has taken place, even though it may not all have come out exactly as you and the rest of the HP three team might have wished, and we will get into that, of course. But most of all, welcome back.

Troy Hudson: Thank you so much, Mat. It's nice to speak with you again.

Mat Kaplan: I bet you remember where we were at the moment we learned InSight had successfully landed on Mars.

Troy Hudson: Oh, very much so. I have a painting of it on my wall in point of fact.

Mat Kaplan: Is that right? Oh my gosh.

Troy Hudson: My partner is an artist, he's incredibly skilled with watercolor and as a Christmas gift, the year that InSight landed he actually made a painting that is a composite of the lander just before the moment of touchdown, and my screaming with joy reaction on the stage at Caltech.

Mat Kaplan: I remember it so well. We shared that celebration with others on the stage, and there were over 1,000 screaming celebrating InSight fans at Caltech with us that day. It was a full house. It will always be one of my greatest Planetary Radio memories. I would love to see that painting.

Troy Hudson: I will be happy to send you a photo of it.

Mat Kaplan: Thank you. Ask your partner, hey, maybe we can put it on the show page, but that's entirely up to him, with proper attribution, of course. There were so much work that followed that great day. I don't think I can begin to imagine what you and the rest of the HP three team, the mole team went through as you worked so hard to achieve the instruments goals, but we did read about some of what you were up to over that period. How long did all of that work last, until you just recently, the team had to say we've done all we can?

Troy Hudson: Almost exactly two Earth years, which is to say just about one Mars year. We first attempted to deploy the mole to dig into the ground at the end of February 2019. Since the end of February 2019, until January 9th of 2021, that's about how long it took.

Mat Kaplan: I read about some of the extensive research that was done to ensure that the mole would do what it was designed to do. Even including high speed X ray photography in a Mars vacuum chamber. Really, it sure wasn't for lack of excellent work, designing this device that that was intended to do something that nobody had ever attempted before on Mars. Do I have that right?

Troy Hudson: Absolutely. The mole itself was a unique device in more ways than one. We've flown things like cameras and even robotic arms to other planets before and landed them on other planets, but the instrument complement of InSight with a planetary seismometer and this heat flow probe that was so tiny, but so powerful and designed to dig so deep, no one had ever attempted something like that without human intervention before.

Mat Kaplan: It was audacious. What were you shooting for? I forget, how many meters would have been ideal?

Troy Hudson: Three meters was our target, but we had a goal of five meters, so that's about 16 feet. The mole itself is about the length of an adult's forearm, it's about 40 centimeters long.

Mat Kaplan: Talk about what you went through. I hate to bring up any painful memories, but I hope that you can take us through the process, from the time when the mole was put in place, and you first started this attempt to drill down below the surface.

Troy Hudson: We'd been on the surface of Mars for a few months at that point, and a lot of things have been going very well. The seismometer was deployed and it was taking data, the rest of the instrument packages on the lander were all working properly. We deployed the support structure to a beautiful site that looked very much like everywhere else that we could reach with the arm, it was ideal in every way we could determine. There was a day when we had sent the commands, the lander had executed them, and we were waiting to get that data back. We were all sitting in the room at JPL. This was of course, well before COVID, so we were all clustered. The team from DLR, and members of the JPL team clustered in our little room, looking at the computers as the data feeds came back through the Deep Space Network.

Troy Hudson: We knew what we wanted to see, and we saw some information, we saw that the mole had indeed turned on and hammered, but the indications we were hoping for that it had made that initial penetration, and we were initially, on that first day targeting 70 centimeters. About little more than two feet, and we didn't get that data.

Troy Hudson: The energy in the room just slowly deflated as we realized, there's something going not how we expected, we're going to have to look into this problem. That was the first indication that something was amiss. As the liaison, and the technical liaison between JPL and DLR, it kicked me into high gear of, okay, let's gather all the data we have, and there was quite a bit of it, from the mole, from the hammer strokes and the tilt sensor. Let's try to interpret this. Let's try to figure out what do we do next?

Troy Hudson: As the days turned into weeks, we kept trying to understand the problem, and we drew out, brainstormed all the possible things that could be causing us problems. Then over a period of months and even ultimately, years, we ticked off those things. That's not the problem. That's not the problem. There was nothing wrong with the mole, there was nothing wrong with the support structure or the tether and even now, today, the device itself is working exactly as it was built to work. The mole is tough and robust, and it's doing great, it's just not quite compatible with the soil we encountered on Mars.

Mat Kaplan: Yet, I'm sure that there were endless attempts to simulate Martian soil with Martian regolith, before InSight ever left for the red planet.

Troy Hudson: Yes, we had a number of test beds, both at JPL and at DLR in Germany, where we tested the mole digging under either ambient Earth conditions or close to vacuum Mars conditions, and a variety of different soil types from what might to you look like loose sandbox sand, to a much more difficult soil that was harder for the mole to penetrate through. We tested it in a number of different materials.

Troy Hudson: We identified there were some cases where the mole's progress wasn't as predictable as others. But everything we expected about the InSight landing area, we thought that it was going to have an easy time with the initial penetration and that the hard part would come when it got deeper and the soil was harder to move. Turns out, that wasn't the case.

Mat Kaplan: What conclusions have been reached about the soil and why it prevented the mole from doing what you wanted it to? I say this to you, knowing that you are a geologist, a planetary scientist with PhDs from Caltech, in addition to your work as an engineer, do we have guesses at what happened?

Troy Hudson: We do. The main culprit appears to be a lack of friction. The mole works very much like a nail. When you nail into a piece of wood, you don't pull the wood out of the hole, like you would with a normal drill, you push it out of the way. That nail stays in place because of the friction of the material around it. The mole, in order to make progress, hammers forward very strongly, but rebounds just a little bit. That rebound has to be absorbed or reacted by something on the outside.

Troy Hudson: When we first put the mole on the surface, it was in this big support structure that had some springs that provided friction to the side of the mole to let it make progress downwards. But once it got out of the support structure, we expected, we had designed it for the soil to provide that friction. But it wasn't doing that, the soil was sticking to itself more than it was sticking to the mole.

Mat Kaplan: You have heard the saying, space is hard. I often add to that, space is hard, Mars is harder. You seem to have had good evidence of that. As the the team came to realize that you were facing this challenge, some of the very innovative work that took place, particularly with that arm that I don't think was it planned that you might be able to use the arm to help the mole Get a grip, so to speak?

Troy Hudson: It was never intended for the arm to interact with the mole directly in any way. The arm had a grapple hook attached to it, which we used to deploy the instruments, and a camera that we use to survey the site and confirm that our instrument placement was as expected. But we did have to invent new processes, new procedures for that arm, and test those. At the same testbed at JPL that we use to practice the deployment, we reconfigured that platform in many significant ways to allow us to practice the lift and removal of the support structure, and then going in with the arm and very delicately, very precisely touching the mole without risking the science tether that came out of it, which is a soft plastic piece with electrical lines in it, we wanted to avoid damaging that.

Troy Hudson: The arm itself is quite limited in where it can move and how precisely it can move. It was never designed for this sort of precision fiddling with the devices. Everything we did on Mars, we practiced extensively. There's a lot of things we practiced in the testbed that we decided were either ineffective or too risky to attempt on Mars.

Mat Kaplan: Some of this work is stretched over... Just even what otherwise might have been thought of as simple operations on Earth, stretched out by necessity for days or weeks, didn't it?

Troy Hudson: It did. When we first arrived on Mars, we had a very rapid cadence, we would send up commands and get the data back and send up the next set of commands every other day. So, three times a week, we were interacting with the lander to survey the site and deposit the instruments. But InSight was always designed to be an observatory. The seismometer would be placed, the mole would get to depth, and then we would just listen, listen for marsquakes and measure temperature.

Troy Hudson: The team that's involved in operating the spacecraft and programming the arm, that team, it decreased over time, the amount of personnel we had available faded out. So, we had to be conscious of the human factors, we didn't want to overwork the team that we still had working InSight. So, things got slower, we ended up interacting with the lander only twice a week, then once a week, then once every two weeks. Over the course of the two year effort to help the mole, we went from rapid fire every other day commanding and data analysis to barely once every two weeks being able to do one thing with the mole. The process, it really did start to stretch out and drag on.

Mat Kaplan: I have to think that as the pandemic hit a year ago, and changed all our lives, it didn't help this any.

Troy Hudson: It certainly made things more challenging for the team. Myself, even prior to COVID, I had suffered an injury, and was recovering from surgery at home when the lockdown came around in March. I was was stuck at home already. But I know the team that has been doing the actual programming of the lander, the commanding, they had to learn to work remotely, which wasn't an entirely unfamiliar thing to us, we have our international partners with the seismometer and HP cubed. We've been doing remote work with teleconferences and email exchanges for a decade, working on InSight.

Troy Hudson: Perhaps for us the transition to a fully remote style of operation was less painful than it is for some other teams that are more used to working physically in the same space.

Mat Kaplan: Well, that's good, I suppose. I apologize, I forgot that it's commonly called HP cubed, not HP three, when people aren't calling it the mole or the Heat Flow and Physical Properties Package.

Troy Hudson: As it happens, the mole story is not over, it may not be able to dig any deeper, but the mole itself, the body of the mole is constructed to also be a temperature probe, a probe of thermal properties. Now that it's fully buried, we can use the mole to measure the thermal conductivity of the soil. It turns out on Mars, that thermal conductivity is very strongly controlled by the amount of pressure, air pressure, gas pressure in the pores.

Troy Hudson: On Mars, from winter to summer, as the ice caps form and disappear, the pressure changes, and we want to measure that change in the soil over the Martian seasons. Now that HP cubed is fully buried and not exposed to the sun or the sky, we can still use the mole as a probe of thermal conductivity for as long as the InSight mission lasts.

Mat Kaplan: What a wonderful surprise, at least for me, and I'm so glad that you've added that, Troy.

Troy Hudson: The main part of HP cubed is the mole, and the science tether it carries with it. But there's another instrument that's part of the physical properties package, which is a radiometer, a device that remotely measures the temperature of the surface of Mars. That, as a separate scientific instrument has been performing excellently since HP cubed was turned on shortly after landing. From that data, we've learned a number of different things related to Mars weather, the influence of Mars's moons on the local environment when they eclipse the sun. A lot of interesting science is being done with that part of HP cubed.

Mat Kaplan: That's excellent news. Of course, we have talked with people like Bruce [inaudible 00:19:38] about the success of that other part of the InSight payload, the seismograph, which has just been spectacular, hasn't it?

Troy Hudson: It has and it's taught us a lot about Mars. It's an exquisitely sensitive device, as you know, and Mars is a much quieter place than Earth seismically speaking. It doesn't have oceans sloshing around. It doesn't have plate tectonics grinding against one another. It doesn't have human activity shaking the surface. Mars is seismically a very quiet place.

Troy Hudson: Since we deployed it on Mars, we've detected almost 500 marsquakes, but they're all less than a Richter magnitude four, they're all very weak and very quiet. Maybe we haven't been there long enough to really hear one of the rarer bigger events, but Mars has surprised us again in that, it's quite quiet.

Mat Kaplan: I think I said this to Bruce on a previous Planetary Radio episode, "Boy, I bet you would have liked to have two more InSight spacecraft sisters at other places on the red planet so that you could have triangulated on some of those earthquake, or marsquake sources?

Troy Hudson: Well, the seismometer itself actually consists of six smaller instruments, three broad baseline instruments, and three short period instruments. These are designed and actually physically positioned in such a way that they can detect arrival directions of signals. With modern computing technology and modern geophysical understanding of wave propagation, there's a lot of information you can glean from a single, well-instrumented, seismometer, like the size.

Troy Hudson: Some of the quakes that we have observed have been localized to a particular region on Mars about 1,600 kilometers away from our landing site that seems to be a hotspot for quake activity.

Mat Kaplan: That's fascinating. Okay, so Mars is not quite as dead as we were led to believe.

Troy Hudson: It seems to be more seismically active than the moon, which I think we expected. But we're still surprised about how quiet it is. But no, there is still seismic activity on Mars, both from Mars itself and then meteor impacts. We believe we have detected a few of those, but the signals haven't been particularly strong. The seismometer, despite its lovely dome, the wind and thermal shield that's placed over it, it's still subject to the local wind environment that sometimes makes it too noisy to hear those very quiet marsquakes.

Mat Kaplan: Fascinating in itself considering how little air there is powering that wind on Mars. Another testament to how sensitive this device is.

Troy Hudson: Well, I mentioned before about the radiometer being used to observe eclipses when the moons of Mars, the tiny asteroid potato shaped moons, Phobos and Deimos, when their shadow passes over InSight, we can see that signal in the power from the solar panels, the temperature measured by the radiometer, and the seismometer itself can sense the deflection of the ground. The ground moves up and down by the smallest perceptible amount, but we can still see that flexion as the shadow passes over us.

Mat Kaplan: Simply amazing. Eventually, that day came when you and the team had to tell the world, "We've done everything we can." Can you take us to that day and your sense of it?

Troy Hudson: Well, what happened was prior to Christmas 2020, things were getting rather difficult on Mars. Dust continues to accumulate on the solar panels. We were in the depths of Martian winter. Upcoming is a conjunction event where Mars will be on the far side of the sun, and we won't be able to talk to it for a while. For all of these reasons, and the fact that there wasn't much more we could do with the arm to help the mole. It was now almost out of reach, we came to the decision that this is one last chance to see if the mole can make progress on its own.

Troy Hudson: Every time we'd help the mole with the arm, either pushing on it from the side or from the back with the scoop, and we hammered, it made progress, it dug down into the soil. It was only when we didn't have the arm quite helping it that we had those horrific back out events that occurred in October of 2019. Fast forward again to Christmas of 2020, we were all in position to do the hammering and then we had our Christmas holiday break. I was able to not think about Mars for a few weeks, which was a blessed vacation. Then we came back, and we were ready to do this final test to see if the mole, we've gotten it deep enough, got enough friction, got enough soil behind it, can it dig on its own?

Troy Hudson: When that data came down, and it showed that it couldn't, it was an odd, weird mix of emotions for me. For two years, I'd been, and we all had been hoping and believed that there was a chance that the mole could get to a place where it could dig on its own. Mars kept teasing us, it kept showing us well, yes, look, you can dig, there's not a rock blocking you, you can go deeper. Oh, but you really have to be touching it with the arm otherwise, it backs out.

Troy Hudson: This roller coaster of emotions of yes, it works. No, it's not working. Yes, this could work. No, that didn't work. Just up and down and up and down. When that final test showed us that it did not go and that the line that we had drawn for ourselves had passed, I was sad, I was relieved, I was in this unusual place of finally being able to start processing the emotions that I had been holding in check for two years. Because the whole process with the mole, for me, being emotionally invested in it was being in the midst of a crisis, a crisis that has not yet resolved.

Troy Hudson: I knew that if we ultimately succeeded with the mole, or ultimately were unable to penetrate, that would affect how I processed the whole experience. But until we got to that point, I couldn't process it, I couldn't really deal with it because I didn't know the outcome. I think everybody in the world now identifies with the feeling of being in the midst of a crisis that goes on for longer than anyone should have to endure. It's a completely different thing with COVID, but the sense of, I'm in the middle of a crisis, and it's still happening, and it's still happening, and it's still happening. That was finally over.

Troy Hudson: Since then, I've spent a lot of time thinking about the good things that came out of this. Despite the fact we didn't ultimately succeed, it was a success, because we got to try, we got to do everything possible with the arm, with the mole, everything we could have done to make this work, we got to try. Even though it ultimately didn't succeed, darn it, we were able to do everything we could.

Mat Kaplan: I'm so glad that you have been left with that conclusion. I hope you know that there were a lot of us out here, around the world, certainly I was one of them, who was following the progress and then the reversals for the mole. The rise in hope and hopes that were then dashed, there were a lot of us pulling for you. I do think that looking at this as a success is exactly right.

Mat Kaplan: More from Troy Hudson is moments away, including the exciting new work he has taken on, and a personal reflection that you won't forget. This is Planetary Radio.

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Mat Kaplan: I want to follow that thread for a bit. I saw on ResearchGate that you have co-authored a lot of papers, many of them documenting development and performance of the mole. How important is it that you have shared, you and the team have shared what you've learned?

Troy Hudson: I think it's very important for anyone intending to attempt a measurement like this in the future, directly applicable to someone who wants to, in the future send a mission to Mars to measure planetary heat flow. Because the same requirements that we tried to meet with the mole will exist for them. You have to dig, you have to get beneath the surface, you have to have temperature sensors that are precise and uninfluenced by the instrument you use to put them there.

Troy Hudson: How you get down to depth, so far, there have been two ways that have been tried; the mole on Mars and the Apollo astronauts with their hand tools and drills in placing thermal sensors on the moon. We've learned again, or it's been reinforced in us that Mars is always a source of surprise. Doing remote geology on another world is challenging and you can't predict what the subsurface is going to be like. Future moles, future attempts to do this sort of measurement, they will keep in mind what we learned about the soil at InSight and make sure that, that at least is a material that their device is suitable for.

Mat Kaplan: Are you familiar with any of the folks over at Honeybee Robotics? They have a-

Troy Hudson: Absolutely, yeah. Oh, yes, Kris Zacny and I are friends and colleagues. I actually took the mole to one of their Mars pressure chambers, because it's an unusual thing. A lot of places have chambers that can go to Mars pressure. But you say I want to put dirt in this chamber and people go crazy. They're like, "No, no, no, no, no, you don't get to put dust in my nice, clean vacuum chamber." But Honeybee Robotics, designing as they do for planetary drilling and sample acquisition activities, they have chambers set up for that.

Troy Hudson: We did some early high speed photography in one of their vacuum chambers as we were troubleshooting some earlier design iterations of the mole.

Mat Kaplan: That is a much better response than I was expecting. Let me tell you what's just happened. Just a couple of hours before we had scheduled this interview at the beginning of this interview, it occurred to me to write to Kris, Kris Zacny, Vice President at Honeybee Robotics, and ask him, what have you learned because of the experience of the mole?

Mat Kaplan: Here's the response that he just sent, I've been keeping an eye on my inbox. "Hi, Mat, I would say one thing we learned is that Mars keeps surprising us every time. Going below the ground is going into uncharted territory with no cameras to tell us what's ahead. Rovers can see obstacles and make a course correction to avoid them, moles, drills, et cetera, can't do that, they need to power through. What InSight did well was using available hardware, robotic arm, to help the mole. They figured out many ways to use what they have to help the mole. A big lesson forward is to think about these sorts of contingencies, how other hardware that's also flying to Mars can help the drill or the mole, or whatever is on board if things don't go smoothly." That's from your friend, Kris Zacny.

Troy Hudson: He said it very well, and it's exactly right. When we were designing the mole on Earth, we were always concerned about would it be powerful enough to get from three meters to three and a half meters, to four meters, to four and a half meters, the deep progress.

Troy Hudson: In all of the tests, or I should say nearly all of the tests we ran on Earth, the initial penetration, getting it buried under the soil was like a knife through butter, it always went so smoothly. But that's the place where we ran into trouble on Mars. Being able to think about what could go wrong, and if that did go wrong, what could we do to help.

Troy Hudson: There had been some discussion very earlier on in the InSight mission, because the robotic arm that we used is a spare from a previous flight mission, and it had the scoop attached to the end of the arm. There was a lot of discussion early on, should be remove the scoop? Should we just get rid of it. We don't need it for anything. It's extra mass, use that mass for something else. Ultimately, we decided to keep the scoop, and I'm glad we did because without it, there would have been even less we could have done to help the mole.

Mat Kaplan: Fascinating.

Troy Hudson: It's also interesting to point out that I am part of a team with Kris at Honeybee Robotics as a collaborator for a different architecture of heat flow probe that has been selected by NASA to go to the moon on one of the upcoming CLPS payloads, the Commercial Lunar Payload System. I'll be working with Kris to do some more attempts at measuring heat flow on the moon in the near future.

Mat Kaplan: Well, congratulations on that. I knew about that work, that particular project by Honeybee, didn't know that you were involved. You have taken us in exactly the direction I was hoping, because I want to talk a little bit more about what you're up to now. You had let me know that you were a deputy lead for something called Team X at the Jet Propulsion Lab. I had never heard of Team X.

Troy Hudson: JPL has an even larger organization within it called the Foundry. The foundry is a place where we help develop mission concepts, and mature them to a place where they're ready to be presented and proposed to NASA. You start out at one end with a scientist has a really cool idea of a measurement that they want to make, and they sketch it out on a cocktail napkin.

Troy Hudson: Well, there's a lot of steps that go from that initial back of the envelope, cocktail napkin sketch, to a multi 100 page document full of engineering analysis and scientific theory and cost numbers and all of the pieces that go into presenting NASA with a proposal for a new mission. The foundry is part of the team that helps that happen.

Troy Hudson: Team X is a concurrent, collaborative engineering team. Proposal teams come to us with a mission concept, a set of instruments, a spacecraft, or an idea of a spacecraft that they want to use to do a mission to look at the Earth or look at another planet or look out into the universe. We bring a team of subject matter experts, experts in power and propulsion, in thermal and communications, all of these people together working in a collaborative environment with interconnected computers, sending data and variables back and forth to one another.

Troy Hudson: As you change one thing, oh, we need a little bit more power in the transmitter. Ah, well, that means the battery needs to be bigger and the solar array needs to be bigger. Well, that takes the mass up, so we have to make the structure bigger. All of these interrelated things that you change one thing and it propagates and ripples throughout the system, Team X is a group of highly skilled engineers that work in real time to make sure all of the pieces are being considered, and see how they flow together. So, at the end, we can provide the team with, this is your mission concept, this is how much we actually think it will weigh, whether it will fit on a particular launch vehicle, how much it might cost, so they can assess where their weak spots are, what areas they need to focus on to improve the design.

Troy Hudson: It's a service we provide both to people within JPL and other investigators from outside who come to JPL to take advantage of that expertise.

Mat Kaplan: In a sense, there are a lot of other missions where you and other members of the Team X team may not be listed as team members, but which you have played an important role on, providing these system engineering skills and expertise. You do consider yourself a systems engineer, don't you?

Troy Hudson: I do. A systems engineer. As such, I get to see lots of really exciting and amazing mission concepts come across my "desk", all of which are addressing different scientific questions that NASA is interested in. Having been solely focused on InSight for such a long time, it's nice now for me, to get to think about all the rest of the discovery and exploration that is happening and will happen in the future.

Mat Kaplan: Let's talk about another mission that is still in the proposal stage, which you are more intrinsically involved with. I know there isn't a whole lot you can say about it, because it is still in competition. But that's VERITAS, which we have mentioned before on Planetary Radio, a discovery mission proposal for a Venus orbiter. What can you tell us about the progress on the planning for this probe?

Troy Hudson: VERITAS is something that I'm very happy to be involved with. The Principal Investigator for VERITAS, Dr. Suzanne Smrekar is a friend and colleague who was the Deputy Principal Investigator for InSight. The VERITAS mission is also a planetary geophysical mission, much like InSight, but a completely different architecture. It's an orbiter that will use radar and specialized optical devices to pierce the clouds and measure in finer detail than ever before the surface of Venus; its composition, its structure, and even its motion.

Troy Hudson: The last time NASA sent a spacecraft to Venus was Magellan in '92, and we've learned a great deal about Venus itself and planets and we've discovered planets around other stars. We have this lovely laboratory right next door of a planet that in many ways is very similar to Earth in size and bulk composition, but evolved along a completely different path.

Troy Hudson: With these refined and improved questions, Sue and her colleagues and us at JPL and our other partners have designed a mission to hone in on the biggest questions that we have about, is there volcanism still happening on Venus today? Was there once plate tectonics and the evolution of continental versus oceanic crust? Something that you can tell by looking at the minerals. No one's been able to do this on Venus before but part of the VERITAS mission is a technique that we have where we believe we can make those measurements for the first time.

Mat Kaplan: I wish you and Sue and the rest of the VERITAS team the best of success as you reach a moment of truth regarding NASA funding. I hope that your analogy that so many people draw between Venus and Earth will not include the runaway greenhouse effect, which has turned that planet into an oven. Let me turn to some other topics, more personally, can I tell you something I love about your email signature block? It's your pronoun preference statement rendered as a rainbow.

Troy Hudson: Yes. It's one of the small ways that I help improve visibility for people of the LGBTQ community. I'm gay myself, and has been a personal policy of mine for almost two decades now that whenever I represent myself publicly, like at a conference, or a news interview, or I'm representing JPL outside, I always wear a small pride pin at my neck or on my lapel, just as a way to let people know whether they're LGBTQ themselves or not, that I am an ally, and a member and a safe space for them.

Troy Hudson: I think representation of people's sexuality is often an invisible thing. It's more invisible than race or gender, even though those are incredibly important, and topical identities of people. The way I look and the way I act, I could pass for straight, that's invisibility, and I want to ensure that that's not what I am, that I am proud and visible in my place as a gay engineer and scientist in this field.

Mat Kaplan: Why it makes that pretty little signature block so important as well. Do you have advice for young LGBTQ individuals who want to follow their dreams of working in space science and exploration? I wonder if this advice will be... How it will differ from the advice you would offer to any young people with these interests?

Troy Hudson: Well, since I became somewhat of a public figure, after the InSight landed, I've spoken to a great many people in the STEM fields who are lesbian, or gay or transgender, and they all have very different experiences. Some of them are fortunate, like I have been, it's never been an obstacle for me, it's something I've always been upfront about. I don't necessarily lead with it when I meet someone in a professional setting. But if I work with them for long enough, it becomes known.

Troy Hudson: I've never experienced any negativity or marginality because of that. Other people haven't been so lucky. The experience of, in one particular lab or at one particular university can be incredibly different for someone because of their sexuality or their gender. My advice to young people looking to go into this field is absolutely pursue your passion, but have a close look at the people you might be working with. When you're trying to choose a school, or a lab or a job that you want to be part of, ensure that you can be yourself there and that you're comfortable in that space. Some spaces are more welcoming than others, and there's many opportunities for you to do the thing that you love in an environment that loves you back.

Mat Kaplan: Great advice, Troy. Just one more. When and how did you fall in love with space exploration and space science?

Troy Hudson: It has been part of my identity since I can remember. Some of my earliest memories are looking through my parents National Geographic magazines, and watching-

Mat Kaplan: Me too.

Troy Hudson: ... the original... Yeah, and watching... I even have a few of them, the one from 1980, with Voyager's picture of Saturn on the cover, the first launch of the space shuttle, I still have those documents. I remember watching Carl Sagan's original Cosmos with my mother. It came out in 1982, and I was barely four years old at the time. But it was fascinating and explained in a way that was understandable, yet still made it seem... Not seem, it's still revealed its beauty of the universe and the wonder, and the fact that we could understand that wonder.

Troy Hudson: That sparked my love of science, in general, and space in particular. I have a tattoo of the solar system on my arms. My bedroom has planetary looking things, and laser lights and all kinds of things. It's my little space cave, and it's also been my office for the last year. It's delightful, and it's just space and planets and geology, rocks, it's always been part of me. I'm glad that I've been able to make that passion, a career, and a place where I can work with other people who have the same passion. Whether they're a scientist, or an engineer, or a manager, or someone who works in any of the other roles that support what we do at JPL and NASA, all of these people are passionate in one way or another. It's great to be in that environment where I'm surrounded by people who want to cooperate, to explore the world and explore the universe.

Mat Kaplan: Thank you, Troy. This has been yet another delightful conversation. I am extremely grateful to you for returning to the show, and sharing everything that we've just talked about. I look forward to another conversation. Please convey the gratitude of all of us at the Planetary Society, to the entire InSight team, and our best wishes for continued success. I do include the mole in that statement, as we explore our solar system and beyond.

Troy Hudson: Thank you so much, Mat, and I will pass on your thoughts to the team. Because the InSight team, it's a small mission compared to something like curiosity. The team is quite close knit and have become so over the last 10 years, and especially dealing with the COVID crisis. We check in on each other and have regular email exchanges talking about what's going on in our lives, because the InSight team really has formed a family and it's been a very pleasurable experience working with all of these people. It's just a good energy in the InSight team. It's exciting to be part of something like that, and I'm sure they will appreciate what you said.

Mat Kaplan: We should all be that fortunate. I am, at the Planetary Society. Keep up the great work and thanks again, Troy.

Troy Hudson: My pleasure.

Mat Kaplan: Bruce Betts on this week's What's Up are next. Time yet again for What's Up on Planetary Radio. We have the Chief Scientist of the Planetary Society, Bruce Betts is here to tell us about the night sky and solve yet another mystery as he provides the answer to the space trivia contest question he posed two weeks ago and it's another one with a pretty good fun twist. Welcome.

Bruce Betts: Thank you, Mat. It's tricky to not come up with tricky questions. We'll get back to that. Let's stick with something less tricky, which is the night sky. Mars and Aldebaran are looking like lovely twins in the evening south, both looking like reddish, fairly bright, but not extremely bright stars. They're really fun to check out. They're very similar in brightness right now. Although Mars is now a little bit dimmer.

Bruce Betts: The 19th of March, they will be hanging out near a crescent moon, making for a more lovely situation. Mars is also passing by the Pleiades and is in between Aldebaran and the Pleiades. So, check out red looking stars in the south, southwest in the early evening. In the pre-dawn, Jupiter, Saturn still low to the horizon in the east. But coming up higher Jupiter is super bright, Saturn up above it looking yellowish.

Bruce Betts: On to this week in space history, it was 240 years ago, Mat, you know what I'm talking about. That's right, William Herschel discovered Uranus 240 years ago. I'm impressed if you know that, or at least that was the official discovery.

Mat Kaplan: I forgot. But yeah. The official, right? Because didn't somebody else find it but not realize it was a planet or was that Neptune?

Bruce Betts: No, Uranus as well. In fact, Uranus from a dark sky is visible, barely, with good eyesight. Conceptually, it is been seen many a time and been observed in older data. But Herschel was first to connect the dots to, hey, it's a new planet, new, so to speak.

Mat Kaplan: Nice work, Will.

Bruce Betts: Very, very good job, William. 15 years ago, a little bit closer back in time, Mars Reconnaissance Orbiter arrived at Mars, it's still taking amazing images, including an image of Perseverance on a parachute just a little bit ago.

Mat Kaplan: Just amazing to see. Of course, people can find a lot of this stuff at

Bruce Betts: On to, Random Space Fact. Probably wondered about Perseverance relative to Curiosity, and how about their relative masses? Well, Perseverance, with larger instruments, new sampling and caching system and modified wheels, makes Perseverance more massive by about 14% at 1025 kilograms, compared to Curiosity at 899 kilograms.

Mat Kaplan: You know, my grandson believes that Perseverance and Curiosity will eventually meet and shake hands and work together on Mars. I have not disabused him of that nice image.

Bruce Betts: Well, that would be unexpected. On to the confusing trivia question, I asked you, how many uncrewed space flights have there been to the International Space Station? There are a few ways to answer this. What did people tell us, Mat?

Mat Kaplan: Apparently, it wasn't too difficult to find the basic answer in the Wikipedia. Damn that Wikipedia. But here is an answer that incorporates some of the confusion that people had from our Poet Laureate Dave Fairchild. "Bruce has asked another of his tricky questions, yes, wandering on uncrewed missions to the ISS. The answer is 135, because the first in air reach the proper orbit, but no ISS was there. This Russian Zarya spacecraft brought up module one, that's all there was for 18 months, the job was nowhere done. Another section came up then on 26th. July, and that's the start of uncrewed flights to castles in the sky." Good work, Dave.

Mat Kaplan: "136, if you include that first flight." A lot of people pointed out that six of them did not make it, there were six failures apparently. I think I know about one or two of those, didn't know there were six. But is that an adequate answer?

Bruce Betts: That is definitely an adequate answer. Sorry about the trickiness. I should have thought this one through. Anything from 129, 130 to 136. What did happen to find us?

Mat Kaplan: found us a brand new first time winner, Matthew [Easson 00:52:51] in Virginia. Man, Virginia has been overrepresented among winners lately. There's something going on here. He said there have been 136 attempts at uncrewed space flights to the ISS, five of which failed to reach orbit and or the ISS, that left 131 successful uncrewed space flights, including modules. He even incorporated that extra little twist there.

Mat Kaplan: He says, "I hope no one edited the Wikipedia." No, apparently not before you got to it, anyway, Matthew. Congratulations, we're going to send you a Planetary Society rubber asteroids, specifically, a kick asteroid, rubber asteroid. Congratulations.

Bruce Betts: I think we've all learned a few things from this special question of trickiness that I may or may not have planned.

Mat Kaplan: Just one other that I'll mention from Darren Ritchie in Washington who sent along a picture, an artist's concept of the SpaceX Starship docked at the ISS. Darren says, "The big question in a few years, does starship dock with station, or does station dock with starship? It's a big rocket. ISS still has it beat.

Bruce Betts: Yeah.

Mat Kaplan: Yeah, let's go on.

Bruce Betts: What was the original name of the Mars InSight mission? Got a It had an official name before InSight.

Mat Kaplan: I have to admit, I don't know this one. But I bet you do, or you will, if you enter and win yourself... We'll do it one more time, and maybe not for a long time after this. If you want your shot at one of those rubber asteroids, here you go. You got until Wednesday, March 17th at 8:00 AM Pacific Time to get in on this contest.

Bruce Betts: All right, everybody. Go out there, look up at the night sky and think about helicopters. Thank you, and good night.

Mat Kaplan: Bruce knows we're under the Navy flight path here from Coronado from the Navy base there and it gets a little noisy sometimes. He's Bruce Betts the Chief of... That's Bruce Betts, the Chief Scientist for the Planetary Society who joins us every week here for What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by its persevering members, Mark Hilverda is our Associate Producer, Josh Doyle composed our theme, which is arranged and performed by Peter Schlosser, Ad Astra.