Planetary Radio • Jul 14, 2021

We’re Going Back to Venus

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20180516 jim garvin

Jim Garvin

Chief Scientist for NASA Goddard Space Flight Center

20180815 sue smrekar

Sue Smrekar

Principal Scientist for Jet Propulsion Lab

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Bruce Betts

Chief Scientist / LightSail Program Manager for The Planetary Society

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Mat Kaplan

Planetary Radio Host and Producer for The Planetary Society

Sue Smrekar and Jim Garvin woke up in June to some of the best news a planetary scientist can receive. Their complementary missions to Venus had just been given the green light by NASA. The VERITAS and DAVINCI principal investigators return to Planetary Radio for a celebration of this announcement and a deep dive into their spacecraft and the mysteries of Earth’s broiling-hot sister world. Bruce Betts adds yet another Venusian mystery when he offers this week’s What’s Up space trivia contest.

Artist's conception of DAVINCI+ probe descent stages
Artist's conception of DAVINCI+ probe descent stages Image: NASA / GSFC
VERITAS
VERITAS The VERITAS mission would map Venus with radar and infrared spectroscopy.Image: NASA / JPL-Caltech

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        Trivia Contest

        This Week’s Question:

        What was the first successful Venus orbiter?

        This Week’s Prize:

        The new paperback edition of The Sirens of Mars: Searching for life on Another World by Sarah Stewart Johnson.

        To submit your answer:

        Complete the contest entry form at https://www.planetary.org/radiocontest or write to us at [email protected] no later than Wednesday, July 21 at 8am Pacific Time. Be sure to include your name and mailing address.

        Answer to the June 23, 2021 space trivia contest question:

        The first and only married couple to fly in space together (that we know of) was Mark Lee and Jan Davis.

        Transcript

        Mat Kaplan:

        The long Venus drought ends now, 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. On June 2nd, Jim Garvin and Sue Smrekar received what had to be among the most welcome phone calls ever. The principal investigators of the DAVINCI and VERITAS missions were greeted by NASA Science Mission Directorate, Associate Administrator, Thomas Zurbuchen with this simple message, "You're going to Venus." Which means of course that we are all going back to Venus, and the European Space Agency made it a hat trick one week later, with word that it will send a spacecraft called EnVision to our sister world.

        Mat Kaplan:

        We are moments away from congratulating Jim and Sue and hearing about their complimentary missions. Bruce Betts will follow up with the Venusian space trivia contest when he joins me for What's Up. It's not in the July 9 edition of the [Downlink 00:01:06], but you know I have to salute Virgin Galactic SpaceShipTwo Unity, the same rocket plane I stuck my head into a few years ago on this show, took its two pilots and four passengers on the ride of their lives, July 11th. It has been a long hard climb, but it looks like the era of sub orbital human spaceflight for all has finally arrived.

        Mat Kaplan:

        I have to qualify for all, of course, since a ticket will set you back hundreds of thousands of dollars. But this is the direct and continuing consequence of ever cheaper access to space. I'm ready to go, soon as the price comes down by an order of magnitude or two. Congrats to Richard Branson and the entire VG team. I look forward to extending the same congratulations to Jeff Bezos and Blue Origin when the first New Shepard flight to carry humans lifts off on July 20th, which is a pretty good day to make a little more history. Just a little bit farther into space is mighty Jupiter, The Planetary Society's new album with our favorite Jovian pictures leads at planetary.org/downlink.

        Mat Kaplan:

        Astronauts made the first spacewalk outside China's new station on July 4th, the work included installation of a robotic arm. And Ingenuity, the Mars helicopter, completed a ninth flight, breaking its own records for Martian flying machines. The little whirly bird is beginning to do its own genuine Mars exploration. I contacted Sue Smrekar and Jim Garvin within hours of hearing that their many years of proposing missions to Venus had finally paid off. Sue is a senior research scientist at NASA's Jet Propulsion Lab in California and still serves as the deputy principal investigator for the ongoing InSight mission on Mars. She also served as deputy project scientist for the Mars Reconnaissance Orbiter.

        Mat Kaplan:

        Jim Garvin is chief scientist at NASA's Goddard Space Flight Center in Maryland. He had that title some years ago at NASA headquarters, and also served as chief scientists for Mars exploration. Some of you may, like me, remember his appearance on the David Letterman show. Sue and Jim join me for an online conversation a few days ago. Jim, Sue at the risk of ruining what's left of my reputation for journalistic impartiality, I want to say, woohoo, this is fantastic. Congratulations to both of you and your teams.

        Jim Garvin:

        Thanks, Mat.

        Sue Smrekar:

        Thank you so much.

        Jim Garvin:

        Hey, we're over the Venus.

        Mat Kaplan:

        It doesn't have any moon, so I guess you can't be over its moons. This is just amazing news. As you know, we were all thrilled at The Planetary Society. We're going to get to that third mission, which has also been approved for second rock, for Venus. But we'll wait a few minutes before we do that. Let me ask both of you, first of all, how you found out that you had made it through the Discovery Program to be selected, green lighted, by NASA? Sue, why don't you go first?

        Sue Smrekar:

        I got the call. I've gotten both kinds of calls at this point, and let me say that this one was vastly better. So yeah, you find out 12, 24 hours in advance that you're going to get a call from Zurbuchen in a time slot, and I feel like I always have to wait at least it's in the second half of that hour. So it's always like, "Can he call? I have to know." So it's nerve wracking. But this time, the wait was worth it, so it was the fantastic call I've been hoping for for a long time now.

        Mat Kaplan:

        We'll have to tell Thomas that was just cruel making you wait till the second half hour. So at that point, you didn't know whether the answer was going to be yes or no, red light or green light?

        Sue Smrekar:

        Correct. You're just standing by the phone, pacing.

        Mat Kaplan:

        Wow. Jim, was that your experience?

        Jim Garvin:

        Let's put it this way, Mat, nerve racking is not the term. I'm a goal-tender in hockey, so I used to get nervous before games, little black discs. This was worse than that. And at 8:04, when the window of time for calling from Dr. Zurbuchen was around 8:00 to 9:00, Eastern, I got a call, and I thought, "Well, this is going to be glum news, as always." This is our fourth time trying to send In Situ mission to Venus. So we thought, "Well, maybe not." And when he said, "Well, you're going to Venus," I almost tripped over my dog who sits under foot of me, her name is Glenda, she likes... the good Venus. And I was literally shocked. I started whipping it up, people were texting me left and right, because we never dared hope, it's one of those things. So for me, I started to play some music in the background to get me psyched. It was a U2 song I like, and I think we found what we're looking for, we're going back to Venus.

        Mat Kaplan:

        Oh, man.

        Jim Garvin:

        So it's great.

        Sue Smrekar:

        Yeah, Jim, you reminded me that the call came at 5:30 in the morning for me, and yeah, I'd woken up at 3:00, I just couldn't sleep anymore, the anticipation was too much.

        Mat Kaplan:

        This is like the stories you hear about the people who get the Nobel Prize call at 2:00 in the morning, depending on their timezone. I suppose in some ways this may be better, this is... You'll be able to enjoy this for so many years to come, and work toward it for so many years to come. What stage are we at now? We had a long ways to go before we see science from these missions coming back from Venus, right Sue?

        Sue Smrekar:

        Yeah, we were selected, but to launch two years later. That means we need to go back to the drawing board with our mission planning. And at this point, we're investigating all of the launch opportunities that fall within that slot that NASA headquarters is looking for. Basically, they pushed this out because of their funding profile, and the desire to have many missions going to Venus, which is worth the weight. But we're starting from scratch, so we don't know exactly when we're going to launch, other than around 2028, so we're working on our funding profile. So basically, we're getting off to a lot slower start than we would have had we gone for the '26 launch.

        Mat Kaplan:

        Jim, you're in the same timeframe, aren't you?

        Jim Garvin:

        We are, and there will be a sequence that NASA headquarters will decide. But we had planned for every possible launch to Venus that we could imagine that woman or man would want, because we knew there could be uncertainty. So right now, we've literally studied every launch from '26 to '33 for DAVINCI because we didn't know. So right now we're looking at an option that we had studied in earnest, as has Sue, that would get us an entry and descent in science and imaging and touchdown in early '31, which is consistent with the NASA headquarters guidelines. And we're getting ready for our big, we call it our science optimization, risk reduction program, we call it SORR. And that's going to give us the ability to buy down the risk as we test the first extremely highly instrumented probe to go to Venus in 50 years. We've already done testing to Venus temperatures, it's interesting how titanium gets charred at that temperature. But we're going to do a lot more now with the funding that NASA's giving us, so we just can't wait to get started. We're literally buzzing, because eight or nine years goes by pretty fast when you're thinking about Venus.

        Mat Kaplan:

        So I've heard from many other PIs. I do want to talk about your spacecraft themselves, and we'll get into a little bit of the detail of that in a moment or two. But I'm just wondering, at this point, have the science packages, have the instruments been locked down? I mean, that's obviously what NASA approved. Is there room still for iterations of improvement on what you'll be taking to Venus?

        Sue Smrekar:

        Well, our instruments are definitely locked down. We have two instruments in a gravity science investigation, but we do a ton of different measurements with those two instruments. At this stage, we're not anticipating adding additional instrumentation, we still have the same funding profile, so that gives us limited ability to do things like that. One of the trades that NASA will have to weigh in on for our upcoming possible launch opportunities is how much excess launch mass we have, and so that is something that allows for secondary payloads to come along. There's been a lot of work through simplex to have small payloads and the options there have really just exploded both for useful and interesting science that can be done at Venus as well as other planets. So personally, I'm hoping that NASA decides to go for one of our opportunities that has a lot more launch mass that could enable additional things to come along. We'll see what NASA has up their sleeve. If they want to give us more money, we can always carry more things, but within our scope, we can't do that.

        Mat Kaplan:

        Jim, I saw your thumbs up to having the ability to bring more mass along. Would you both like to bring along some, well, I don't know, CubeSats, other nano sats, micro sats?

        Jim Garvin:

        Well, Mat, first, I mean, our payload is locked down like Sue's and we have two analytical instruments very similar to those on Curiosity rover, actually going to go on a flying rover to Venus, is the way we look at our mission. And those instruments are both from the Goddard Space Flight Center and JPL, they're the centerpiece of our mission as we transect that atmosphere, so those are locked down. We also have a new class of imaging system, we call it our eyes wide open, which will allow us to see Venus below the clouds at scales that will compliment, we hope, very helpfully Sue's mission. So we'll see things that scales down to sub meters as we come in optically. So those things, the optimization there will be more tailoring our entry profile.

        Jim Garvin:

        But we do have two remote sensing payloads that will fly on two high-visibility flybys of Venus that will give us very unique day-side Venus atmosphere views. We expect to do the first ultraviolet hyperspectral imaging to look for mystery absorbers that are really been confounding Venus scientists with one of them, and the other experiment will allow us to was to make little movies, kind of like Star Trek approaches the Venus in the ultraviolet as we can be watching the clouds and the absorbers move.

        Jim Garvin:

        Now our spacecraft, built by Lockheed Martin will carry us, release our probe due to a descent telecommunications to get our data set back from the probe entry mission. But then the spacecraft's still alive, we'll have assets on that spacecraft that NASA can choose to use, we can go back to Venus and go into orbit, it could carry simplex payloads, we could do other kinds of experiments with the payloads we have that would extend beyond what we've been doing. So like Sue, we would love to carry other payloads, but they're not ours. We also have a student collaboration experiment that we're very excited to have over hundreds of students involved that will allow us to make measurements down near the surface of Venus, never before made by a woman or man. So we're trying to do our best to open that Venus frontier for everyone.

        Mat Kaplan:

        I see that both of you are in tight with Lockheed Martin and a lot of other agencies, in your case, Jim, a number of the other NASA centers. Sue, your mission has a particularly international flavor where you're working with, what, three other space agencies?

        Sue Smrekar:

        Yeah, one of our instruments is provided by the German Space Agency, our spectrometer, Venus Emissivity Mapper, so that's the instrument that is going to allow us to, for the first time, get global measurements of surface composition, particularly around the iron type of mineralogy that we have on the surface, and look for volcanism, recent volcanism, active volcanism, just ton of exciting measurements. So we have that coming from the German Space Agency, and we're collaborating with their radar group, it's actually a terrestrial radar group, there have been a lot of collaborations between JPL and this group outside of Munich. We're going to have them help us out with the software, the processing radar, processing software, following on for the many interferometric SAR missions that have been flown around the Earth.

        Sue Smrekar:

        From the Italian Space Agency, they're a very big partner, they are providing a piece of our VISAR instrument, our X-band radar instrument. In terms of electronics, they are also providing much of our telecom system, they're providing our high gain antenna, and the integrated deep space transponder. So they're very big partner. And then we have a contribution from the French Space Agency, they are providing part of our telecom system as well. So we have an international science team as well. And we actually have participation from a couple of other NASA centers as well on our science team. We have someone from Marshall and some are from Goddard.

        Mat Kaplan:

        Yeah, I did see that there was some crossover between your two centers, JPL and Goddard on both of these missions. Jim, I also want to note, because I love to mention them, that those four cameras that will comprise the instrument left on your orbiter, the orbiter portion of your spacecraft, are going to be for provided by Malin Space Science Systems, those people who have done such an amazing job of revealing a lot of our solar system.

        Jim Garvin:

        It's very exciting for me because in graduate school, one of my best friends is Mike Irvine, who is the lead engineer on all of our cameras. And we actually have five cameras, one will be our descent camera, and [crosstalk 00:15:12] camera that will actually make 3D machine vision views of the surface to complement Sue's global views as we measure and infer composition. But also, the four cameras on our flyby spacecraft are also developed by Mike and he and I've worked together most of our lives. So it's nice to be going to Venus together, and really in that partnership that we've been trying to do since 2008, so it's been a while.

        Jim Garvin:

        But we also are very excited, Mat, because we have partnerships that are essential to our mission at multiple centers, a key instrument from JPL, our tunable laser spectrometer from Chris Webster is part of a centerpiece, our own mass spectrometer build at Goddard, but also we have strong partnerships with Langley and NASA's Ames, and a strong partnership with the University of Michigan as part of some of our [inaudible 00:16:00] development, as well as other universities that are really integral to our overall team. And of course, Lockheed Martin provides our critical aeroshell system that'll allow us to get into the atmosphere of Venus, and release our probe, our flying chemistry lab rover, if you will, as we descend through that atmosphere with eyes wide open.

        Mat Kaplan:

        I'm going to follow up on your probe a little bit here, before we come back to, Sue, your VERITAS spacecraft, and talk about that probe. You see pictures of it, artist renderings of it already descending down to the surface. The thing looks like a little pressure cooker to me, for good reason, right?

        Jim Garvin:

        Well, our probe, which we call our descent sphere, because it's inside of an aeroshell and gets all packaged up, is about a meter in diameter, so she's about the same size as the spherical belly of the Venera landers that went to Venus so successfully in the '80s and '70s, from the Soviet Union, or the then Soviet Union. And she's a titanium pressure vessel, aero-fairing system with spin veins around her mid drift to stabilize us so we can do the high resolution, high sensitivity imaging. She also has a bunch of different inlets, they're kind of the sniffer system that allows us to sample the atmosphere. We'll make hundreds of measurements and scans of the chemistry of the atmosphere in ways that have never been done before for any planetary atmosphere.

        Jim Garvin:

        The other thing is, we've tested a flight test unit of our probe, which we're very proud to have shown some VIP visitors just a couple of weeks ago, to full Venus conditions. So when you see this thing up close, and you realize how kind of big it is... I mean, she's a beast with four primary instruments, a student payload, all this pressure and temperature accelerometers, the telecommunication system, which is a two way system that we're working on with the Applied Physics Lab. So we'll be up regulating and down regulating our data rates as we descend, so we can get the most data back from our chemistry and our imaging experiments. So this probe is the essence of our mission, I like to say it uses natural vertical mobility. [inaudible 00:18:06] fly on Mars, we'll be descending on Venus, thanks to the way Venus works.

        Jim Garvin:

        One of the things we'll probably do, Mat, which I think will be exciting for the people of Earth, is we'll experience the change as we hit the super critical co2 fluid down nearest the surface. Sue's mission will sense with radar, we'll sense that with our probe, and for the first time trying to understand that because that's something about the Venus atmosphere that's really weird to think about how that gas behaves in a non ideal way.

        Mat Kaplan:

        Obviously, you're going to descend under parachute, but then that parachute is released, and the last, what, kilometer or so, you're just in free fall. Why is that?

        Jim Garvin:

        The last 40 kilometers we're in free fall. So we will release our parachutes after we ingest the gas samples from the middle atmosphere that will represent the bulk atmosphere, when we'll actually ingest and process those gas samples to look at the noble gases. Who doesn't love the noble gases? But we especially do, and don't forget xenon. I always like to tell kids that. But anyway, after we do that, we'll release the parachute, and we will free fall, changing velocity from about several 10s of meters a second to a final terminal velocity down around 10 or 12 meters per second. That's about as fast as a boat hitting a dock at a speed you'd rather not like, but still survivable.

        Jim Garvin:

        So literally, our final five kilometers we'll be fluttering down, twisting a little bit in the low Venus winds, collecting images and chemistry samples that will tell us about the water history of Venus, the unique surface atmosphere interactions, the surface landscape at scales of sub meters, we'll make topography maps that we hope will be useful to Sue's mission for calibrating the backscatter from their X-band radar, which could be sort of a ground control point. We may even have a radar cross section that could be seen by Sue's radar, so-

        Mat Kaplan:

        Oh, wouldn't that be something?

        Jim Garvin:

        It's be really cool.

        Sue Smrekar:

        Can we add a corner reflector, Jim?

        Jim Garvin:

        I know, Sue, that's what people ask me. A spherical probe [inaudible 00:20:04] that would scare a dog is not the ideal corner reflector for radar, unfortunately. But-

        Mat Kaplan:

        I'm just going to throw in that anybody who has seen a lot of sailing ships with funny little objects up high on the mast somewhere, that may have been a corner reflector, so that it just make them a little more radar visible. Listen, you said it, it has been 43 years since those pioneer probes descended down through the atmosphere, thick atmosphere. Nearly as long since the last of the successful of those Soviet Union missions, those remarkable balloons and landers, those still stunning images that Venera landers were able to pick up from down on the surface. It really does seem like we're long overdue, doesn't it? I mean, the advances in instrumentation must be tremendous.

        Jim Garvin:

        Well, Mat, for me, I mean, I was first introduced to that question by [Tim Much 00:21:05], and Jim had in the late 1970s, right after Pioneer Venus did its first probe mission, and they said, "We're going to go with a Venus mapper," that was then called VOIR, who doesn't like VOIR, it turned into Magellan later, but no matter, both great names, and I wrote my thesis on that, those data sets from the Soviets. So we never imagined going back, really, until the community started thinking post Magellan, what can we do? We've been trying ever since, so it's like building a castle in a swamp, it sinks, and eventually you get one.

        Jim Garvin:

        But now we have the kind of vision systems, the kind of spectrometers, the kind of things to do from orbit, that Sue will be doing, that are literally... they were unimagined back at that time. So the Venus we saw in the late '70s and '80s, that then Magellan mapped, is going to just pop. And I promise you, I like to tell the kids, there's a pony in there, trust me, this will be spectacular for all of us.

        Mat Kaplan:

        And thank you, your holy grail reference was not lost on me. Sue, speaking of improvements in technology, I mean, I think back to the Magellan orbiter, it had that giant radar dish. I don't see one on VERITAS. Is that a sign of how far things have come?

        Sue Smrekar:

        Yeah, well, in the 30 years since Magellan, yes, things have come a long way. Yeah, we have just our two parallel radar transmitters and receivers, they both transmit and receive. So yeah, they're just over three meters long, we have a separate antenna that does the communications, and then our radar antenna. So yeah, things have changed just tremendously, the technology is completely different than it was back when Magellan flew. Yeah, we don't need this enormous antenna in order to get super high resolution data. So many things have enabled that, including our onboard processing, for the majority of our data, we get thousandfold reduction in the volume of data before we send it down.

        Mat Kaplan:

        Wow, that's amazing.

        Sue Smrekar:

        Yeah, we can send raw data, but mostly we send back data that's been compressed by a thousandfold without loss. This is part of the technology that's been developed to support just this suite of radar investigations for the Earth that are doing everything from mapping topography, but also mapping the ocean surface and so many climate change related investigations. So we've really just advanced, not only in the hardware, but also in the software that we'll use to create this just tremendous global data set. When Magellan flew, the topography that we got back was better than we had for most of the Earth, so it was just advanced then, and now, we're going to get a similar huge leap forward.

        Mat Kaplan:

        That's exactly where I was hoping to go. I'm also thinking, of all the people listening to this as an MP3, which is nowhere near the thousandfold compression that you're going to be achieving with data coming back from Venus, is there more you can say about how big a jump this is over what Magellan was able to deliver? Because, of course, I still look at a lot of those Magellan images and they're pretty amazing, still.

        Sue Smrekar:

        Sure, sure. So for our topography, we're having a [inaudible 00:24:26] magnitude, a factor of 100 better resolution. So if you looked at the island of Hawaii, you would have about 25 pixels for Magellan there, they range from about 12 to 25 kilometers in size. So if you looked at Hawaii, you could get the idea that maybe there's a couple peaks there, so you'd have some sense that there's a volcano there. But with the data that we'll get from VERITAS, we'll see the calderas, we'll see the fault scarps, we'll see individual flows. The surface, vertical resolution is six meters. So many of the flows on Hawaii, you can actually see in that scale of topography.

        Sue Smrekar:

        We really focused on optimizing our typography, because radar is fabulous, we've learned so much from those images of Magellan, but it's an imperfect way to view the surface, and Jim has referenced this, you need to have a so-called dielectric contrast in order to pick out things on the surface. So you can have adjacent flows, lava flows, that you couldn't distinguish one from another, because if they have basically the same surface roughness, you can't see them, or you can't see their boundaries in the radar.

        Sue Smrekar:

        Our image data will also be an order of magnitude better, a factor of 10 better than Magellan data and have really good signal to noise, we expect to see things that we never imagined. We've gone back to Mars many times with an order of magnitude increase in resolution, similar to moon. And every time we've done that, we see things we never imagined were on the surface. There are so many questions that we of course, want to answer right now, but it's always the discoveries that we just haven't anticipated that will completely revolutionize our thinking about our sister planet.

        Mat Kaplan:

        Maybe this is a good time to bring up how your missions will complement each other. You've already hinted at that, but it sure does seem like the sum is going to be greater than the parts, Jim?

        Jim Garvin:

        Exactly. In fact, this is a dream come true, I think for all of us, I mean, certainly for Sue and I and our teams. I mean, the [inaudible 00:26:46] is going to Venus. And a probe mission can measure chemistry, like a rover mission on Mars can measure chemistry and rocks, we'll be doing it through the atmosphere, and inferring composition of rocks, but we're only one dimension of the problem, and it has to be integrated into the global perspective. In fact, we hope our probe descent data sets, the imaging ones, composition at meter scale, typography at meter scale, from our camera systems we'll produce kind of trading sites that can be fed into Sue's global modeling of the whole planet for one particular region on Venus. So we'll sort of produce the airborne ground truth, kind of like a drone's eye view, so Sue can then extrapolate that over the whole planet. And her typography, I just have to say, exactly as she said, is going to be so important.

        Jim Garvin:

        When we went to Mars, dare we did so with a laser altimeter in the '90s, and saw the Mars at that scale that Sue will be getting for Venus, it changed everything, literally everything. And people said, "Oh, we don't really need that." Well, we did, and now we're going to get it for Venus. Just imagine, there's 450 million square kilometers of real estate to map on Venus. That's a lot of ground to cover, and so we're going to be seeing that third dimension, and integrating that story, topographically, to what we see locally to the chemistry story about the history of water, and the bulk inventory versus the inventory that was lost, and the sources of that, will couple together to give us this more holistic view of the planet, which is really the way to explore.

        Jim Garvin:

        We've done that before, Cassini at Saturn, some of the Mars program, Mars Reconnaissance Orbiter at Mars, for example. But now we're going to do it at Venus with two missions that will look at the planet and it will provide some of the atmospheric boundary conditions and the lapse rate, that temperature variation from the clouds down to the surface, every 10 meters we will have that measurement for the first time that will help calibrate some of the emissivity data that Sue will be mapping the whole planet with. I think there's a lot of incredible natural synergisms that... And we share teammates too, so that will be even more exciting to work together.

        Mat Kaplan:

        More from Sue's Smrekar and Jim Garvin about their upcoming Venus missions will arrive after this very short break.

        Sarah:

        There's so much going on in the world of space science and exploration, and we're here to share it with you. Hi, I'm Sarah, digital community manager for The Planetary Society. Are you looking for a place to get more space? Catch the latest space exploration news, pretty planetary pictures, and Planetary Society publications on our social media channels. You can find the Planetary Society at Instagram, Twitter, YouTube, and Facebook. Make sure you like and subscribe so you never miss the next exciting update from the world of planetary science.

        Mat Kaplan:

        Let's talk about some of the other questions, the mysteries that remain about this very strange world and how you hope to illuminate them, in some cases literally with radar. Sue, volcanoes, you talked about viewing those calderas? Do we have a shot at finding out, finally, if there is active volcanism on Venus?

        Sue Smrekar:

        Absolutely. Yeah, we have many different ways to detect change on the surface. In terms of our spectrometer, we do a number of different things, we look for the chemical variations that are a signature of recent volcanism. And that approach was pioneered, shall we say, by the Venus Express mission. So we get some hints of that, and we'll get... With our spectrometer, it's designed to observe the surface of Venus, the spectrometer that was flown on Venus Express was designed to look at comets for the Rosetta mission. So it was just incredibly awesome that they were actually able to see the surface of Venus with that instrument. So we're going to have vastly better signal to noise and six channels versus one.

        Sue Smrekar:

        So with that, we can look for the chemical evidence of recent volcanism, basically, volcanism that's been erupted on the surface, but hasn't fully chemically interacted with the atmosphere. We can look for active volcanism, although even if we were flying around the Earth, we'd have to be very lucky to see that, because when flows erupt on the surface, they immediately start crusting over, the thermal signature goes away rapidly because of the crust that forms on the surface. Now, if there's a lava lake, or some crazy thing going on, we can certainly see that. But you just have to get very lucky to see recent or active volcanism.

        Sue Smrekar:

        We will also look for water coming out of volcanoes, so near surface water vapor. Again, we would have to be lucky, but if we see that, that's just a fundamental observation and answers a really big question about Venus, is there still a lot of water in the interior of Venus? So to actually see that coming out of the planet today, would say that it has at least as much water in the interior as the Earth, because you need several weight percent of water in the magma to escape that huge density in the Venus atmosphere. And we see lavas like that, see outgassing like that for certain lavas on the Earth. So to actually get that signature, yes, we'd have to be lucky, but it would be a game changer that says, "Yes, interior Venus is still spewing water today."

        Sue Smrekar:

        Then our radar instrument has a number of ways to look for activity too. We will also be comparing our data sets to what Magellan took, we translate from one frequency to the other, there are algorithms to do that, and they've been used effectively on the Earth. So we'll look for changes between Magellan, we'll look for changes between our cycles, and perhaps most excitingly, we will do repeat pass interferometry. So if you've seen an image, those very colorful images of [inaudible 00:32:36] motion on the San Andreas Fault, where they have the kind of rainbow diagram showing the levels of deformation on the surface, that's what we're going to do for Venus.

        Sue Smrekar:

        Now, that takes a ton of data. So we can only do them in limited locations. But we have lots of data sets that suggest activity like the Venus Express, and we'll be acquiring our own data sets, and the community has lots of ideas of things that may be active on the surface. And we're definitely going to be getting community input to target this very high value resource. I mean, to see something actively [inaudible 00:33:09] on the surface, that would be just incredibly valuable, scientifically, and of course, exciting.

        Mat Kaplan:

        This all seems to be evidence for something that I've heard you've said, Sue, which is that if we're going to answer a lot of the questions we have about Venus, we have to look to the interior, which makes me also think of Mars InSight, a mission that you still have a lot to do with.

        Sue Smrekar:

        Yeah, and that's another mission that was a long time coming. Very soon, later this month, we're going to get the first really precise measurements of the interior from InSight are going to be published in science. So look for those later this month, it'll be just really exciting to get the core size, the thickness of the crust, information about the mantle. So yeah, we've tried to be very, very careful in analyzing our data because it is noisy and when you do seismology on another planet, you really have to train yourself to very carefully discriminate noise from signal. So we've taken our time and we feel very excited and confident about the results that will be coming out later this month.

        Mat Kaplan:

        That's exciting. That's something to look forward to. And we follow the InSight mission pretty closely on Planetary Radio and throughout all of The Planetary Society's channels.

        Sue Smrekar:

        In addition to our two instruments, we have a gravity science investigation. We're going to be measuring the gravity field of Venus much more precisely than we have been able to do in the past by using two way K-band data, which is more precise than the X-band and S-band that's been used in the past.

        Mat Kaplan:

        Let me stop you for a second. This is using the Doppler changes that have been so useful on a lot of other missions, including by Cassini at Saturn.

        Sue Smrekar:

        Absolutely, yes. It's almost for free, not quite, but almost for free, and we anticipate getting the first useful measurements of core size to within about plus or minus, say 75 kilometers, which allows us to get an idea about the chemistry of the core, and determine whether it is fully liquid or solid and liquid. And that's just the first order information that you need to be able to say, "Why the heck doesn't Venus have a dynamo?" It should have a dynamo, right? It should have a dynamo, just like the Earth, it's crazy that it doesn't, we see them on icy moons, we see them at Mercury, why not at Venus? That's a really exciting thing that we are anticipating is being able to better understand the interior structure and refine our measurements of estimates of thickness of the crust and so forth.

        Mat Kaplan:

        Jim, I can tell you're in complete agreement, because I've seen a lot more thumbs up and a lot of head nodding. We have so much more to learn about this world. For example, might we find out if plate tectonics are at work on Venus, as we know they have been on Earth for billions of years?

        Jim Garvin:

        Well, that's actually the job of the VERITAS mission with the elegant correlations of gravity and topography, and I suspect Sue's mission will resolve that or at least the onset of that. Our job with DAVINCI is to look through the chemical lenses of the story, which are analytical and often definitive. And that's how we've resolved issues about origin of water on Earth, evolution of the water cycle on Mars, we have the tools on DAVINCI to look for the isotopic ratio signatures of recent volcanism through isotopes of helium, for example. We also, using our ultraviolet instrument, our technology demonstration experiment, will be able to look for trace gases in the upper clouds involving sulfur and oxygen and other species that could be indicators of volcanism, as was suggested decades ago. So we'll be able to look for the other side of the chemical puzzle that Sue will look for up close.

        Jim Garvin:

        For me, I mean, the plate tectonic question couples to the role of water in the crust, in the interior as Sue was getting at. And right now, the Venus atmosphere is relatively water rich, shockingly, but it's that interplay with the surface. So the one measurement we have from Pioneer Venus, Tom Donohue, and people and Dave Grinspoon have been working for decades, showed us the possibility that Venus was possibly a water-rich planet. And so we're going to resolve that by making 10 times better and 10 times the number of measurements to see that story as we translate the atmosphere. And so putting Venus into the question of it being a habitable world for billions of years like Earth is a big part of that agenda that will then link it to the history of plate tectonics, or mobile lid tectonics, perhaps a better term for Venus, whatever the right term is, Wagnerian or not.

        Jim Garvin:

        So these are all parts of the puzzle pieces that, in some sense, we named our mission DAVINCI because Leonardo put together puzzle pieces in science, art, technology and engineering. And we think these missions together, our mission, just because we named it that, are going to do that for Venus, she is a masterpiece, and we haven't seen anything yet, Mat, seriously.

        Mat Kaplan:

        Sue? Plate tectonics. I mean, something's going on up there, right? Don't we see some evidence of subduction?

        Sue Smrekar:

        I believe we absolutely do see subduction, and it's such an important process to understand because plate tectonics started on the Earth billions of years ago, and we have very little evidence, very little rock evidence from that time period. There's a lot of theories about how plate tectonics started, there's a lot of theories about how subduction starts. But we just don't have the definitive data to answer that question for the Earth. So for Venus, not only is it Earth's twin, with respect to its size, its bulk density, we think it has... Because of its climate change, because of its incredibly hot surface temperature, the lithosphere, the outer strong part is hot today, and that's what was going on in early Earth. So we have this ability to go back in time to conditions that were likely present on early Earth. So we can investigate this question, "Is there subduction on Venus today? Could it be active? What are the conditions that are allowing that to form?" That could be an avenue to understanding how Earth might have started out with subduction, how plate tectonics could evolve.

        Sue Smrekar:

        It's these really important questions like, what's the role of temperature, what's the role of water, that we need to understand to begin to really know, how can plate tectonics start someplace else? We learned so much about its links to habitability on the Earth. As we go to look at exoplanets, we really want to know, are they likely to have plate tectonics or not? So we have this real opportunity to be able to understand, to look for that first phase, developing plate tectonics. And yeah, in the topography, if the San Andreas Fault were there on the surface of Venus, we wouldn't see it in the [inaudible 00:39:58] data we have now. But with VERITAS, we can really begin to map out the subtle variations in typography that will tell us so much about the tectonic evolution.

        Mat Kaplan:

        I latched on to, in particular, one thing you said there, which is about learning about exoplanets. And it just seems like, boy, we've got so much more to learn about our own neighborhood, if we want to understand what's going on across the galaxy, right, Jim?

        Jim Garvin:

        Well, exactly. In fact, that's one of the emphases of DAVINCI and several of our teammates are deputy PI, Giada Arney, Steven Kane in the University of California. One of the things we want to do is turn Venus into the exoplanet next door as basically a ground control point or a planet control point for looking beyond, and in the era of James Webb Space Telescope that will be launching this year. We have the tools to see exo-Venuses spectroscopically using transmitted exoplanetary spectroscopy. A lot of words, but the ability to actually tease out chemistry of atmospheres of planets in the Earth/Venus size range, and start to explore the evolution of a habitable zone.

        Jim Garvin:

        DAVINCI will provide the measurements from the top of the clouds, ultraviolet spectroscopy, all the way through the atmosphere to look at what an exoplanet next door really looks like, compositionally, spectroscopically, and in terms of its evolutionary history. We may be able to tell the difference between our Venus, this hot, climate-change run amok world that Sue was just talking about that we're going to get to know so well with VERITAS and DAVINCI, and others, compare it to a former state of Venus, like some of the modelers are predicting, that might have been a much more climate habitable time with long-lived surface bodies of water. Think of this Mat, if Venus harbored surface oceans of liquid water for billions of years, why might it not have generated those onset conditions for the chemistry of what we call life?

        Jim Garvin:

        And whether agnostically we explore that or through other techniques, that is a vital question as we look beyond, and to tell that there are other Venuses around stars that we can sense with astrophysical observatories that are in the habitable state, not in the current Venus state, would be a breakthrough. So our team, together with the astrophysics community, of course, are dying to attack that problem, and make Venus the exoplanet next door.

        Mat Kaplan:

        I'm going to throw out a plug here for last week's Planetary Radio when we visited the James Webb Space Telescope and talked to people like Bill Oakes, the project manager for that, that grand instrument that's going to reveal so much. Jim, you have to think after talking about the possibility of past biology on Venus, I'm sure you were expecting this question, I can sum it up in one word, phosphine.

        Jim Garvin:

        Well, Mat, who doesn't love swamp gas? I mean, anyone who's been to a Halloween show and has probably thought about phosphine, but phosphine, which is a phosphorus hydrogen compound, is just one of many of the exotic compounds that could exist in the Venus atmosphere in different amounts, different mixing ratios. The tentative detection or not, of that species from elegant Earth-based spectroscopy done by many investigators, is a reminder to us of how much we don't know. We don't even know the chemical context of the atmosphere in which that phosphine could or could not exist.

        Jim Garvin:

        So one of our jobs for the community on DAVINCI is to actually produce measurements about the chemical context, and the chemical cycles of all the carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur gases throughout the atmosphere. That context is the context that any chemistry lab experiment would take place first, before you leap to the question, "Well, is that phosphine a bio signature? Is it a natural consequence?" Many scientists on our team believe there's other phosphorus bearing gases would be more likely, more abundant, more detectable, and more important. Likewise, those involving sulfur, and the sulfur in the Venus atmosphere, of course, is a very important component constituent in that atmosphere.

        Jim Garvin:

        Our job is to fill in those chemistry gaps, so we can ask questions about the cycles, the timing, connections to volcanism, connections to erosion, connections to change and styles of tectonics, global resurfacing, history of climate states in a climate atmosphere system. All those are big questions. Without the chemical boundary conditions, as with geo-physical ones, you can't go anywhere. You can speculate and say, "Well, if it's like Earth, it's this. If it's not, it's this." We're not going to be speculating after these two missions fly. And we'll be able to ask, "Is there phosphine? How much? If it's not there, what else is there? What other exotic molecule that we haven't discovered is there that we need to pay stock to?" Phosphine is detectable in astrophysical observatories, why it's interesting, but there's others too. So our job is to fill in all of those.

        Mat Kaplan:

        Sue, you've called Venus, "A cosmic gift of an accident." What do you mean by that?

        Sue Smrekar:

        Well, there's a great cartoon, XKCD, I don't know if you've seen that site-

        Mat Kaplan:

        Oh, God. My hero, yeah.

        Sue Smrekar:

        ... but they have this cartoon, space without the space. Venus is actually 41% of the rocky material in our solar system. Earth is 43%, 45%. So these two planets are the vast majority of the rocky material in our solar system. And really no two bodies, maybe other than asteroids, are more similar. They are just this incredible control case of ability to take one hypothesis and apply it somewhere else. And the 30 years since Magellan has gone by, I've never lost interest in Venus, because we continually learn new things about the Earth. My view is always, well, okay, so that works on the Earth, should it work on Venus? And if not, why?

        Sue Smrekar:

        It gives us the ability to both explore the early evolution of the Earth through its hot lithosphere today, it gives us the ability to study the climate, it's a place... Runaway greenhouse was discovered, people have continued to do things like suggest, "Oh, we should put sulfur particles in the upper atmosphere to slow down climate change." Venus scientists have come back and said, "Yeah, that's not going to work, because we see that same chemical breaking down in the atmosphere of Venus." So there's just so many synergies, both for understanding the atmosphere, understanding tectonic evolution, and, yeah, there really aren't any two planets more similar, and no place is more similar to the Earth.

        Sue Smrekar:

        As we see all these crazy exoplanets being discovered, there's still one, it still is not an exoplanet, that is more similar in size and illumination to the Earth than Venus. So it's absolutely the place that we need to go to understand, are we unique, we're still the only place that has life, right, that we know of, and what got us to this point? Venus is the place to go and understand what makes planets habitable. And to model the kind of processes that we'll never be able to observe on an exoplanet. We have to get these models of how rocky planets evolve right, by going to Venus and understanding how these two twin planets evolve down different paths.

        Mat Kaplan:

        An Earth-sized laboratory, and we're finally going back. I have to think that our co-founder, Carl Sagan, would be very, very proud. I promised we would get to that third mission that we learned barely a week after NASA announced the green lighting of your missions. The European Space Agency's also going back to Venus with EnVision. Sue, I saw that your JPL colleague Scott Hensley is a project scientist for its radar system, and Scott is working with you on VERITAS too, isn't he?

        Sue Smrekar:

        He's a double project scientist.

        Mat Kaplan:

        What's it going to mean to have yet another... I mean, a third member of this armada, Jim, that you were talking about?

        Jim Garvin:

        Well, for me, it's even more spectacular because the complementarity of vantage points taken by EnVision with a different type of radar, a polarimetric radar that can see scattering properties that are uniquely related to history of erosion, possibly sedimentary processes on Venus, coupled to the scales of observation that will take Sue's and magnify them down through the capacity of the JPL provided [inaudible 00:48:29] radar will be spectacular. Every time we've done that, as Sue mentioned, for Mars, we took the challenge of going from the Mars Global Surveyor Odyssey to Mars Reconnaissance Orbiter, people said, "You shouldn't do that." Well, we're still doing that, and it's still showing us benefits.

        Jim Garvin:

        EnVision will do that. But add to that, even more spectroscopy of the atmosphere and the surface and putting those things together with an additional radar experiment that will do [Nadir 00:48:54] base sounding. It's a magical mystery to our... And so my suspicion is by putting together the medley of all three of these data sets, plus others that may come from other nations, Mat, that are being discussed, that I suspect will happen, we will see this brilliant star next door, the terms Sue used was really so elegant, Venus is the sister we didn't know we lost or had, that we better get to know because God only knows, as you can imagine.

        Jim Garvin:

        So I think the interplay and relationships between these missions, the synergies, I mean, DAVINCI will fly by Venus and look for atmospheric phenomena that will be tested in time by VERITAS, and tested again in time by EnVision, starting to connect the time series back to Pioneer Venus orbiter, and of course, Magellan, and then Venus Express, and Akatsuki. I mean, this is the way planetary programs are developed, and that builds better understanding. It's not just the sum of the parts, it's much bigger. And when you get all the science communities together, thinking of Venus, that has been difficult without missions, at least in the United States, I just think the prospects for learning will be so great. We'll see the history of habitability in a world next door that can tell us about those things that Sue was mentioning about early histories of plate tectonics and other crustal things.

        Jim Garvin:

        And let's not forget, Mat, the other distinguishing thing of Venus, [inaudible 00:50:17] of the rock record, it also has this massive atmosphere. For a rocky planet to have an atmosphere like Venus takes a lot of work, Mother Nature doesn't favor that. We need to understand that. And so EnVision plus VERITAS plus DAVINCI will give us that depth of understanding. So all the kids out there today, those young girls and boys will have a Venus to study. That's our job, really, to me.

        Mat Kaplan:

        Sue, I'm going to give you a chance to get the last word here as you think about what's ahead of us over the next, let's say, 15 years, because that'll get us out there with all three of these spacecraft and probably terrific science being returned?

        Sue Smrekar:

        An absolute revolution in our understanding of rocky planets.

        Mat Kaplan:

        Well said. Thank you both, congratulations again. As you can expect, The Planetary Society, this show, I hope, will be carefully following the progress of both of your efforts. And I look forward to checking in periodically to see how things are coming along. And then of course, to the arrival of Venus of your spacecraft. Thank you so much, folks.

        Jim Garvin:

        Thanks, Mat. We're delighted to be here and what a ride it's going to be.

        Sue Smrekar:

        Absolutely, it's been fabulous.

        Mat Kaplan:

        DAVINCI, principal investigator, Jim Garvin, and VERITAS, principal investigator, Sue Smrekar. Time for What's Up on planetary radio. Here is the chief scientist of The Planetary Society, that is the astronomer and scientist and project manager, Bruce Betts. Welcome back. I saw Venus, you couldn't miss it. I think I had a Venus shadow, man, it was bright.

        Bruce Betts:

        Yeah, it's impressive. Brightest natural object in the sky besides that pesky moon and sun.

        Mat Kaplan:

        So what else is going on up there?

        Bruce Betts:

        Well, let's start with Venus. Everyone can participate in seeing Venus, but you need to look in the early evening, over in the west, fairly low to the horizon. But as Mat just said, he was surprised by how high up it was. Is that right?

        Mat Kaplan:

        Yes, absolutely.

        Bruce Betts:

        But still, look in the early evening, fairly low in the west. Mars is still very close to Venus, a little bit below it and much dimmer, over 100 times dimmer, looking reddish, tough to see and it's going to drop away within days basically. Venus will drop away but it'll take weeks and it's really easy to see, as you saw. As you see a saw, seesaw.

        Mat Kaplan:

        I love seesaws.

        Bruce Betts:

        We should do a show about that. We should record What's Up while on a seesaw.

        Mat Kaplan:

        On a seesaw. Yeah, all right. Make a note of that.

        Bruce Betts:

        Okay, coming up now in just the mid evening, the 9:10 pm kind of range over in the east, you got really bright Jupiter, and to its upper right, yellowish Saturn, and the moon will be hanging out between them, roughly, on July 24th. Good evening, start with Venus in the early evening, catch Jupiter and Saturn in the mid evening. We move on to this week in space history which, oh, everything happened this week in space history. That is not true. But it's funny how there's some weeks that are a little thin, this week I'm going to do five things in a row quickly and I'll still miss some. So we got 1965, Mariner 4 does the first ever successful flyby of Mars. There's that... What is it, Apollo-

        Mat Kaplan:

        Oh, yeah. The one with two ones, yeah, 11.

        Bruce Betts:

        Yeah, they did something in 1969. Oh right, first humans to walk on the moon 1969. 1975, Apollo-Soyuz launched and connected in space. 1976 Viking 1, first really successful Mars lander. Oh, and I'm just going to do one more, 2015, first Pluto flyby by New Horizons.

        Mat Kaplan:

        And he could go on.

        Bruce Betts:

        I could, but I'm not going to because we also need to get to random space fact.

        Mat Kaplan:

        Oh, I like that. I like that. The range of your vocal talent there is fantastic.

        Bruce Betts:

        Oh, thank you. So it's well known, in other words Mat knows it, that the Soviets had several successful Venus landers. But did you know the US has had a Venus lander?

        Mat Kaplan:

        What?

        Bruce Betts:

        Although, somewhat unplanned as such. Pioneer Venus Multiprobe, which has two other names, Pioneer Venus 2, or even Pioneer 13, was launched in 1978, it had four probes that were atmospheric probes designed to study the atmosphere, but two of them actually survived landing, one of them transmitted data for over an hour.

        Mat Kaplan:

        I think I read that somewhere, but I forgot, otherwise, I'd have mentioned it to Jim Garvin, because we talked about the Pioneer Multiprobe, but... Wow, that's just incredible. I mean, they weren't designed to do that, were they?

        Bruce Betts:

        No, they were designed as atmospheric probes and they actually hit pretty hard, pretty darn hard. So it's even more amazing. It was one of the small ones that survived for a while. So there you go.

        Mat Kaplan:

        On to the contest, and we have some fun stuff that some of you folks submitted.

        Bruce Betts:

        I thought we might. I asked you, who was the first, and I think only, married couple to fly together in space? How did we do?

        Mat Kaplan:

        I begin with this from [Rod Sandry 00:55:49] in Australia who chastises you somewhat, Bruce. He says, "Bruce, the Google Gods had this one figured out 248 million times in six tenths of a second. I am not going to earn a degree in space trivia contest when you make it easy for us."

        Bruce Betts:

        Oh, wow.

        Mat Kaplan:

        I think it's just fine that you made this fairly easy, I think it's great.

        Bruce Betts:

        Try to mix it up. I get in trouble when they're too easy with some listeners and trouble when they're too hard with others. So I'll just keep asking them and hopefully most of you will be sort of happy.

        Mat Kaplan:

        I think you're in the sweet spot. And I know, [Lewis Igo 00:56:27] was in the sweet spot. This is going to make those of you out there who keep entering every week and have not yet been chosen by random.org, it's going to make you a little crazy. his first time entering from Minnesota, and he got it right, I believe. He says that that married couple, Mark Lee and Jan Davis?

        Bruce Betts:

        That is correct, on shuttle flight STS-47.

        Mat Kaplan:

        Which was quite a flight as we will learn in moments if you don't already know. Congratulations, Lewis, you are going to get that stunning Planetary Radio T-shirt. And we will get that into the mail to you from chopshopstore.com real soon. A lot of people mentioned the Russian who... It was sort of a half marriage that took place in space because he was the commander of Expedition 7 on the ISS when he married his wife Ekaterina Dmitrieva via video link. [Edwin King 00:57:32] was one of those who submitted that, Edwin in the UK. Here is a portion of a poem submitted by [Jean Luhan 00:57:40] in Washington, "And then there's Yuri Malenchenko, while during his Expedition 7 shot married his love back here on Earth and literally tied the cosmo-knot." I thought you'd like that.

        Bruce Betts:

        Well played. Cosmonaut.

        Mat Kaplan:

        All right. [Nade Heathcock 00:58:03] in Florida, he says it was Barney and Betty Hill. Do those names mean anything to you?

        Bruce Betts:

        Lost in Space?

        Mat Kaplan:

        You're close. You're very close. I remembered this but I had to check it just to make sure my memory was correct. He says, "I couldn't resist one with the 60th anniversary coming up on September 19th," loves the podcast, "Barney and Betty Hill were the first two people, married couple, who claimed to be abducted by aliens." So yeah, kind of lost in space.

        Bruce Betts:

        Okay, kind of glad I didn't know that. But now I do.

        Mat Kaplan:

        So like you said, STS-47, big deal. Mae Jemison was on board, also the first Japanese astronaut, Mamoru Mohri, who was commanded by Hoot Gibson, who also married an astronaut, Dr. Rhea Seddon, that came from Martin [Hodgoski 00:58:59] in Texas. Mark [Littell 00:59:02] in Northern Ireland says, "There are or were seven US married astronaut couples." He adds, "Cupid's arrow can achieve orbital velocity it seems." Joseph [Purtray 00:59:15] in New Jersey, "Did Flash Gordon ever married Dale Arden?" He's thinking the first married couple depicted in space were the Jetsons.

        Bruce Betts:

        Okay, we need to really work on separating reality from fiction.

        Mat Kaplan:

        Finally, this contribution from our poet, [Laureate Dave Fairchild 00:59:35] in Kansas, "Davis and Lee were the first married couple to fly into space as a pair. NASA found out they were secretly married a few weeks before they went there, but NASA, however, up there on Endeavour placed one on a red team, one blue. You may try to prank us, but you don't outrank us. So we're going to chaperone you."

        Bruce Betts:

        Yeah, so what I thought was interesting was they apparently were secretly married weeks before, which NASA had a rule against flying married couples together. But they were allowed to fly together because it was so close to the mission at that point that they flew and were put on different shifts.

        Mat Kaplan:

        Well played, you too.

        Bruce Betts:

        Did they tie the astro-knot? Sorry, I can't get enough of that.

        Mat Kaplan:

        That's derivative, that's... Jean, you get double. We'll give you double royalties this week, Jean, okay? For those two naughty jokes. We're ready to go on.

        Bruce Betts:

        Talking Venus. You like talking Venus, you just talked Venus. What was the first successful Venus orbiter, go to planetary.org/radiocontest, first successful Venus orbiter.

        Mat Kaplan:

        You have until Wednesday, July 21st at 8:00 am Pacific Time to get us the answer. And here's a nice prize for somebody out there. Sarah Stewart Johnson, remember her, the great conversation we had with her about her new book, The Sirens of Mars? The paperback version is about to come out, it's about a week away as we record this, from Crown, Crown publishing, and you're going to get a copy of The Sirens of Mars if you get away with being the winner of this week's brand new contest from Bruce. That's it. We're done.

        Bruce Betts:

        All right, everybody, go out there, look at the night sky and think about cheese. Thank you and good night.

        Mat Kaplan:

        Just last night, there were people eating pie, we were watching the show Atypical and they were constantly eating pie in that show, and now, ever since then, I really have wanted apple pie with a slab of cheddar cheese. Doesn't that sound good? I don't know. Are you a cheese and pie guy or are you an à la Mode person?

        Bruce Betts:

        I'm an à la Mode person. When the option of ice cream presents itself, always take it. Otherwise cheese is good.

        Mat Kaplan:

        That's Bruce Betts, nothing cheesy about him. He's the chief scientist of The Planetary Society. He joins us every week here for What's Up, and I must acknowledge the wonderful pun that you made last week which I let slip by, his locks that he would give up for rocks. Planetary Radio is produced by The Planetary Society in Pasadena, California, and is made possible by its hotter than molten lead members. Join at planetary.org/join, and please for me, leave us a rating or review in Apple podcasts. Marc Hilverda and Jason Davis are our associate producers. Josh Doyle composed our theme which is arranged and performed by Peter [Schlosser 01:02:39] at [Astro 01:02:40].