Venus is so close, and yet so far in terms of our understanding of its history and geology. Early in its history it may have had an ocean just like Earth’s, and volcanoes may be erupting there today. The only way to find out more is to take the latest technology to Venus and take a closer look! NASA is sending two missions to Venus this decade and participating in a European Space Agency mission there, too. Lori Glaze, director of planetary science at NASA, discusses these missions and why she’s so excited about what we’re about to learn.

Jim Green:The bright morning star and evening star turns out to be the planet Venus. What is NASA doing about exploring that next?

Lori Glaze:There’s every indication that Venus started out very similar to Earth with lots of water, that it would have been a water planet in the past.

Jim Green:Hi, I’m Jim Green. And this is a new season of Gravity Assist. We’re going to explore the inside workings of NASA in making these fabulous missions happen.

Jim Green:I’m here with Dr. Lori Glaze. And Lori is the director of Planetary Science at NASA headquarters in Washington, DC. In fact, Lori got this fabulous job after I left to become the chief scientist. Welcome, Lori, to Gravity Assist.

Lori Glaze:Thanks, Jim. Great to be here.

Jim Green:Well, you know, before coming to NASA Headquarters, you were at Goddard Space Flight Center. What did you do there?

Lori Glaze:Oh, gosh, when I was at Goddard, I did a lot of different things. I was a scientist. So I did a lot of science where I did research on volcanoes across the solar system, including volcanoes on Mars; and volcanoes on Venu; and volcanoes on Io, the moon of Jupiter. And so that was my, my main science background. But I also got really interested in developing new mission concepts that could explore the solar system; in particular, exploring Venus.

Jim Green:Well, you know, we’ve got a lot of missions that have gone to Venus in the past. So we do know a few things about it. Can you tell me why the fascination with this beautiful planet? Where is it in our solar system?

Lori Glaze:So Venus is actually our closest neighbor in the solar system. It’s our closest neighbor. And it’s actually closer to the Sun than us as well. So Mercury, and then Venus and then Earth. And what’s so fascinating about Venus is that both Earth and Venus are about the same size. Venus is a little smaller, but not much. So they have similar gravity. They formed in the same part of the solar system, they probably formed at about the same time. And so we would assume that they were all made up of the same materials, they started in the same place. And you would think that they would have evolved very similarly. But they didn’t, they have, somewhere along the way, they took very, very different paths. Earth and Venus went very different directions.

Lori Glaze:Where Earth now has an oxygen rich atmosphere, we have liquid water on the surface, we have an environment that’s very comfortable for us as, as humans and for lots of different types of life. On Venus, the atmosphere is almost all carbon dioxide, about 95% carbon dioxide, and there’s so much of that carbon dioxide. It’s such a thick atmosphere that it has a really strong greenhouse effect, meaning that the solar radiance comes into the atmosphere, but the thermal energy can’t escape and it is incredibly hot at the surface.

Lori Glaze:So what we really want to understand is, as we’re discovering thousands of new exoplanets, it’s hard for us to tell when we look at them, are they going to be exo-Earth’s or exo-Venus’s? And so the more we understand about Venus, the more we’ll be able to understand exactly what makes an Earth? What makes a planet become Earth-like or makes a planet become Venus-like?

Jim Green:Well, you know, Venus’s atmosphere is so thick as you say, 90 times our atmosphere, that it almost acts like a fluid on the planet. And so the temperature and pressure is the pretty much the same anywhere you go on the day side and the night side. Pretty remarkable.

Lori Glaze:It is remarkable. I’ll tell you another fun fact about Venus. You’re absolutely right that the temperature doesn’t change with day to night, it changes from equator to pole, but Venus actually also rotates backwards from Earth, and it rotates on its axis so slowly that a day on Venus is longer than its year, meaning that it takes longer to rotate on its axis than it takes for it to make the entire trip all the way around the Sun. It’s a weird place, but definitely fascinating.

Jim Green: (laughs) But you love it.

Lori Glaze: I do.

Jim Green:The only blue planet on our solar system today is Earth. And there’s been a lot of discovery at Mars, indicating that Mars was a blue planet. Also, early on in its history. What about Venus?

Lori Glaze:Well, we have lots of indicators that make us think that yes, Venus once had a lot of water. We have measurements from the Pioneer Venus large probe mission in the 1970s, that had some measurements that made us think that yes, there was an enormous amount of water present in the past. We also know that the, the molecules that got delivered to Earth that would have been a source for water on Earth would have also come to Venus. And there’s every indication that Venus started out very similar to Earth with lots of water, that it would have been a water planet in the past. But we just know that somehow over time, that atmosphere heated up, and a lot of that water was lost to space.

Jim Green:Well, you recently announced two new missions, what we call Discovery missions, and they’re going to Venus, what are they all about? Tell us what are they gonna do?

Lori Glaze:I am really excited about both of these missions, two missions to Venus, one of them called VERITAS and the other one called DAVINCI.

Lori Glaze:And these two missions are really highly complementary. They’re both interested in helping us answer questions about how a rocky planet with an atmosphere, how that those planets form and how they evolve over time. But they go about the different observations in very, very different ways to help us answer some of those questions.

Lori Glaze:So the VERITAS mission is an orbiter, it’s going to go into orbit around Venus, and it’s going to carry with it an amazing synthetic aperture radar system that actually has two antennas and allows it to, in one orbit, collect topography and understand the the topography of the surface of Venus understand the elevations of the ground below. That’s a really challenging thing to do on Venus, because there’s such a thick atmosphere that you can’t see to the surface in the normal visible wavelengths. You have to use a radar system really to see through and measure this topography. Do they’re going to get the highest resolution topography we’ve ever seen for Venus globally, so that’ll be amazing.

Lori Glaze:They also are going to carry an infrared instrument that does allow them to kind of poke through and see through the clouds at certain wavelengths and measure how the surface reflects in those wavelengths, and how it emits energy and those wavelengths. And that’ll help tell us more about the crust and its properties.

Jim Green:In addition to that, isn’t it going to be looking for hotspots, perhaps volcanoes?

Lori Glaze:So VERITAS will be looking for potential hotspot. That infrared detector will be able to look for things that may be emitting energy at higher temperatures. And so perhaps there may be some indication of active volcanoes on Venus. An earlier instrument flown by European Space Agency thought that maybe they saw hints of that in these infrared wavelengths. And so we’ll see with VERITAS, you know, whether we can see similar signals on Venus.

Lori Glaze:Many of us are really intrigued by the idea that Venus could have active volcanoes today. And Venus being almost the same size as Earth, the interior should still be hot. And one of the main ways Earth loses its heat is through volcanoes. And so it seems like Venus should still have active volcanoes. We’ve actually seen some evidence of that, possibly some measurements, where we’ve seen sulfur dioxide, big spikes, where there’s a sudden increase in the amount of sulfur dioxide that we can see at the cloud tops of Venus. And we know on Earth, that volcanoes put out a lot of sulfur dioxide. So some people have suggested maybe the sulfur dioxide we see on Venus might be from volcanoes. We’ve also seen in infrared images, looking at the emissivity of the surface spots, that look like they may be warmer, and that may be active lava flows. So we don’t really have a smoking gun yet. But there’s, there’s a lot of good indicators. And certainly, it seems like a place where volcanoes should still be active.

Jim Green: The other discovery mission is DAVINCI+. So once again, a fabulous mission. What is it supposed to do?

Lori Glaze:So the DAVINCI mission is really a cool mission to fly a small probe, which is about a meter across, a big sphere. And that mission is going to send that probe down into the Venus atmosphere to measure the gases in the atmosphere. And there’s going to make the types of measurements that you can’t make from space, the only way you can make these measurements is to actually suck in the gas and sniff it and, and measure directly the chemicals that are contained in the gas.

Lori Glaze:So it’s going to measure gases like helium, neon, argon, krypton, xenon, all of these gases that are called noble gases because they don’t like to play nice with the other gases, they don’t like to combine with anything. And so those gases are really good indicators, kind of like little molecular fossils in the Venus atmosphere, to let us see back into what Venus’s atmosphere was like billions of years ago, and how it may have changed over time.

Lori Glaze:So very cool measurements, also going to measure water vapor in the atmosphere, and it’s going to measure two different kinds of water, the heavy water which is deuterium and the lighter water, which is hydrogen. And by measuring those two, it’ll help us understand the story of water in Venus’s past, because we think Venus had a lot more water way long ago and billions of years ago that has all escaped, and that deuterium and hydrogen, the hydrogen escapes more easily, we’ll be able to measure that ratio, and that will give us a sense of how much of that that water has actually been lost.

Lori Glaze:And then finally, it’s also going to measure the trace gas chemistry, all of the chemicals like sulfur dioxide, carbonyl sulfide, carbon monoxide in the lowest part of the atmosphere, it’s never been measured before. And then I guess I should say one more thing it’s going to do: Its carrying a camera, which is always awesome, because as it comes down at the very end of its descent, it’s going to take pictures that we can see for the first time what some of the really rugged terrain on Venus looks like up close. So that’ll be really cool as well.

Jim Green:Is it expected to survive all the way down to the surface?

Lori Glaze:Yeah, the DAVINCI probe is expected to survive all the way to the surface. Now that is a hard thing just by itself. It takes about an hour for that probe to descend all the way through the atmosphere. It’s not like Mars where you have seven minutes of terror. It’s more like an hour of, of extreme nervousness as it comes down. And the atmosphere of Venus of course is very, very hot. Very, very hot near the surface — 850, 900 degrees Fahrenheit — you’ve got incredible pressures, essentially, it’s about 100 times more atmospheric pressure than on Earth. And so it’s like if you were half a mile underwater, so really not, not a comfortable place for a spacecraft. But it should survive all the way to the surface. It doesn’t have to survive after landing. But, you know, we’ll see if perhaps it’s able to take one more picture once it once it lands.

Jim Green: So let me get this straight. We’re going to drop a probe off at Venus. It’s going to fly through sulfuric acid. It’s going to encounter enormous temperatures hot enough to melt lead and crushing depths. How do you build such a probe?

Lori Glaze:It’s not an easy thing. So I’ll tell you that the, the probe itself is actually made of titanium. And the titanium is very resistant to the sulfuric acid. It’s also, structurally, it’s one of the strongest, but lightest metals that we can use. So we’re we really want to keep our mass down as low as possible. So that titanium lets us be really strong, you know, resist the pressure of that really dense atmosphere, but also be lightweight.

Lori Glaze:Now, we have to stay cool and that is really hard. And so I will tell you that what we’re going to do with DAVINCI is it is going to carry something we call a phase change material. So think about ice cubes, right? That as the ice melts, it, it keeps your water at the same temperature doesn’t get warmer or, or colder, right until all of the ice is melted. On DAVINCI, they’re not going to carry ice cubes, of course, they carry some type of a salt material or a wax material and, you know, depending on what they’ve chosen. And that as it melts, helps keep the inside of that probe all at the same cool temperature, cool relative to the outside temperature, so that all the electronics and the instruments can operate at the same temperatures that they are comfortable operating at.

Lori Glaze:You know, that’ll melt pretty fast. And it, you’ve, you’ve only got an hour to get through. So they just have to carry enough to survive that hour. And I’ll tell you another fun fact about Venus, the world record for surviving on the surface of Venus is two hours by one of the Venera landers that was launched by the Soviet Union. So, you know, two hours is the is the best we’ve done so far, surviving in that high temperature environment.

Jim Green:Indeed, Venus is so hot, we don’t expect any liquid water on its surface. So as it has evaporated the water, there’s been chemical interactions in the upper atmosphere and it creates sulfuric acid. So is DAVINCI+ able to punch through the level of sulfuric acid in the clouds of Venus?

Lori Glaze:It will punch through the, the clouds. It’ll come right down through there. And that’s exactly where it’ll start making its measurements is when it’s in the clouds, in those sulfuric acid clouds. And I will just say one note, there was a mission that went to Venus, back in the 1970s, called Pioneer Venus. And they actually when they tried to measure the atmosphere, they actually sucked in one of those sulfuric acid droplets, and it clogged up their tubes. And so they weren’t able to make all the rest of the measurements that they wanted to make. So DAVINCI has lots of plans for not letting that happen to make sure that they are able to make all the gas measurements they want to make all the way down to the surface.

Jim Green:Well, you know, Venus doesn’t have a magnetic field and the solar wind continues to strip its atmosphere. But yet it seems to have such a thick atmosphere. How is that possible?

Lori Glaze:That’s always a great question because we think a lot about you know, that what we know about the Mars atmosphere, and we know that Mars has lost so much of its atmosphere. And a lot of times that is explained by the fact that Mars doesn’t have a magnetic field. And so it’s unable to protect itself from the solar wind. And then you go to the Venus case, and you say, “but how is that true at Venus because Venus also has no magnetic field to protect itself from the solar wind?”

Lori Glaze:But there are some other factors that are at play here. One is that Venus, of course, has much higher gravity than Mars does. And so losing your atmosphere from the solar wind is, is partly a balance between the gravitational pole that’s holding the atmosphere in and then that, that stripping from, from the solar wind, and there may also be other processes in play. We’re actually still trying to better understand how exactly the Venus atmosphere is lost.

Jim Green: Now in addition to our two discovery missions going to Venus, European Space Agency also announced their mission to Venus. Is NASA involved in that too?

Lori Glaze:We are absolutely involved in that mission. So the European Space Agency, they also selected a Venus mission. It’s called EnVision, and NASA is really proud to be participating with ESA on that mission. We’re actually going to be contributing a synthetic aperture radar. It’s similar, but actually quite different, from the radar that’s going to fly on VERITAS. And this radar system is going to be focused on taking very high spatial resolution images in targeted locations on Venus. So that will be awesome.

Lori Glaze:It also is going to carry a ground penetrating radar, and a spectrometer that looks across several different wavelength regions. And so that will really help us characterize the atmosphere, and also, in some cases, be able to penetrate down to the surface. So these missions are all really complementary and between VERITAS, DAVINCI and EnVision, it’s going to be a great resurgence of Venus science. And we’re looking forward to a coordinated effort across all of our international science community.

Jim Green:Well, what’s the order of launch between these three missions?

Lori Glaze:Right now, the scheduled plan is that VERITAS would be the first one to launch. At around the 2028, I believe is the, the schedule right now and then followed shortly by DAVINCI in 2029. Possibly 2030. But very close there together. And then the EnVision mission would follow after those two. Its baseline is to launch in 2032. But I know ESA is actually looking at trying to see if there’s a way to launch a little earlier. So they’re going to launch very close to each other. This will be a really synergistic exploration of Venus at the end of the 2020s.

Jim Green:Right, and so with VERITAS, first getting that broad picture, enabling then EnVision to really hone in on just the right places. That will be spectacular.

Lori Glaze:Absolutely, that’s exactly the way this should happen. That you know, VERITAS is going to do the global mapping, EnVision’s going to do the high-resolution imaging. And then you know, DAVINCI is going to add on top of this incredible in situ chemistry measurements.

Jim Green:Wow, can’t wait.

Jim Green:So you’re the director of planetary science at NASA. And I would say you have the job to be the top advocate in the federal government for planetary missions. Can you give us an overview of what your job is like?

Lori Glaze:Oh, my gosh, yeah. And you’re right. The main purpose of this job or the main responsibility is to be that advocate, and to really speak to the amazing science that we’re doing. And the planetary science portfolio right now is just chock full of incredible science missions. Last time, I counted, I think we have 39 missions in our portfolio that are including our participation on partner-led missions going to Mercury, we got now missions going to Venus, we have a whole slew of missions going to the Moon. We’ve got a bunch of things at Mars, we’ve got missions at Jupiter, we’re going to have a new mission going to Europa, the moon of Jupiter.

Lori Glaze:We’ve got missions all the way out into the Kuiper Belt. So it’s incredible science, you know, my day-to-day job is I get to learn about the incredible science going on on all of those missions. I get to talk with the scientists that are, you know, developing those missions, and then talk to the scientists, of course that are then using the data and making the fantastic new discoveries. It’s, it’s an amazing job, as you well know.

Jim Green:I do, I do, but I have to tell you, I do appreciate how hard it is. It’s, to me, it’s the toughest job I ever had. I greatly admire you and all the efforts that you’re doing to make this work and it’s just really spectacular. Well, what’s the next mission you’re going to launch?

Lori Glaze:So the next mission that we’re going to launch is called Lucy. And the Lucy mission is going to launch in October of this year. And Lucy is a really interesting mission that’s going to go study these unusual asteroids that are trapped in Jupiter’s orbit. These are unusual in their location, and also in the unique ability of this one mission, one spacecraft to actually visit seven different asteroids that are out there, a great alignment of orbital dynamics, and the physics of our solar system that allows this spacecraft to go visit multiple asteroids.

Lori Glaze:And these are amazing remnants of our early solar system and by visiting lots of different asteroids will help tell us that, that early story of how that, the, the solar system formed and where the larger planets migrated during that early formation time. So it’ll be a fantastic and exciting mission.

Jim Green:Well, Lori, I always like to ask my guests to tell me that event or person place or thing that got them so excited about being the scientists they are today. I call that event a gravity assist. So Lori, what was your gravity assist?

Lori Glaze:I would say that my gravity assist was an event that happened in May, actually on May 18, 1980, which was the day that Mount St. Helens erupted in, in Washington State. And at that time, I was in high school. And I was living in Bellevue, Washington just up, up the highway from, from where Mount St. Helens erupted. And there was just something about that whole time and the, the leading up to the eruption, when there was a lot of discussion about what was happening at the volcano that I just found absolutely fascinating.

Lori Glaze:And I didn’t directly go into studying volcanoes when I went to college. But I got my bachelor’s in physics. And I had an opportunity when I did my masters to apply my physics background to studying volcanoes and understanding how lava flows move and how the ash columns rise up into the atmosphere.

Lori Glaze:And I really attribute that event back at that time when I was in high school to what really got me excited about science and got me super excited about volcanoes, and then ultimately led to my real fascination with planetary science.

Jim Green:Well, Lori, thanks so much for joining me and discussing the fantastic things that you do to make NASA’s planetary missions happen.

Lori Glaze:Thank you.

Jim Green:Well join me next time as we continue our journey to look under the hood at NASA and see how we do what we do. I’m Jim Green, and this is your Gravity Assist.

Credits

Lead producer: Elizabeth Landau

Audio engineer: Manny Cooper