EPISODE 76: DAVINCI

Transcript

Mike Sekerak: DAVINCI’s not only going to another planet but it’s going to smell and taste the Venus atmosphere while collecting more images of the Venus surface than all other missions combined.

Deana Nunley (Host): Welcome back to Small Steps, Giant Leaps, a NASA APPEL Knowledge Services podcast where we tap into project experiences to share best practices, lessons learned and novel ideas.

I’m Deana Nunley.

NASA has selected two new missions to Venus, Earth’s nearest planetary neighbor. We’re kicking off our podcast for 2022 with a two-part series on the Venus missions — DAVINCI and VERITAS — starting with a conversation with DAVINCI Lead Project Systems Engineer Mike Sekerak. You may remember Mike from our Lucy episode a few months ago. Mike, it’s great to have you back on the podcast.

Sekerak: Deana, so happy to be back.

Host: It’s been over 30 years since NASA has visited Venus. What do we know about the planet?

Sekerak: You’re right. It has been a while since NASA sent a mission to Venus. We had the Pioneer Venus probes in 1978, then had an atmospheric probe and Magellan was a radar mapper in 1989. And that was the last NASA-led mission, but it hasn’t been completely ignored. ESA’s had Venus Express and JAXA Akatsuki, but Mars really has dominated planetary exploration in the late 90s. But Venus is so much more similar to Earth with its comparable size and mass, but our planets took two very different planetary evolution paths. And that’s something that we really want to try to understand.

You think about it, the Venus surface conditions are 95 atmospheres of pressure. It’s almost a hundred times the pressure of Earth. There’s thick carbon dioxide atmosphere with sulfuric acid clouds and the surface temperature is about 480 degrees C or about 900 degrees Fahrenheit, hot enough to melt lead. That’ll both crush you, melt you and burn you with acid, which is a great place to spend a vacation. (laughter)

So, how did our twin planet go down such a different path than Earth? And those are the types of things that we do already know from the missions that have gone there from all over the world, including the former Soviet Union had a lot of missions. But there’s still so much more that we need to learn about Venus. And so, what we want to try to understand with these missions is how it evolved. There’s a lot of volcanic activity on Venus. There’s these large plateaus called tesserae that are about the size of large states in the United States. Can you imagine a plateau the size of Texas or Alaska? How did they form? And what are they made out of? And did early Venus have oceans? Was it more hospitable early on? Which a lot of scientists think that it was wet and different environment than it is today. That’s what we want to try and avoid is how Venus went down that path and hopefully how we can make sure Earth doesn’t go down that same path.

Host: What are some of the unknowns or the mysteries about Venus that could prompt discoveries by the DAVINCI mission?

Sekerak: Well Venus, it’s shrouded in cloud. It’s shrouded in mystery, literally with this thick atmosphere that it has — again, this very thick carbon dioxide atmosphere. One of the things that DAVINCI’s going to do with this atmospheric probe is that we’re going to drop a probe down into the deep atmosphere of Venus. And DAVINCI’s an acronym. It stands for the Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging. And as the name implies, we are going to actually drop a probe down through the atmosphere and sample the atmosphere all the way down to the surface and especially the deep atmosphere around less than 16 kilometers. And that’s where 66 percent of the atmospheric mass is. And to date with all the missions that have been there, we don’t have any definitive in situ data from that region, but it holds a lot of the information about the atmosphere and orbital sensing just can’t get it because it’s too thick. They’re mostly blind to what’s going on in that region. We’ll actually sample that with our descent probe.

And so, we’ll help answer some of the questions about how the atmosphere formed and how it evolved. And that has a lot of implications for other planets outside of our solar system, that it could be in the habitable zone. We’ll look at some of the history of the water abundance on Venus and did it have oceans? Our measurements will be able help answer some of those critical questions.

And of course, those who follow the Venus news, phosphine was quite a bit in the news in 2021 and its potential implications for what it can mean about conditions on Venus and in potentially life and we’re not going to go there, but we will make some measurements that will help with the phosphine discussion within the atmosphere.

And we’ll be taking images, far more images than have ever been taken with all the other missions combined of the actual surface itself. Again, because of cloud cover, you can’t take images from orbit of the actual surface. And we’ll be able to help constrain some of the geologic history and the weathering with those images that we take during our descent, as we descend upon Alpha Regio, which is a large tessera about the size of Alaska. It’s about 1,500 kilometers across and about a kilometer higher than the surrounding terrain.

And the last thing, and this is the thing that actually really excites me the most is its implications to exoplanets. Some of the scientists call Venus ‘the exoplanet next door’ because as we’re discovering more exoplanets with all these different exploration platforms, a lot of them are closer into their stars and could be very, very similar to Venus. Understanding Venus will help us with that exoplanet exploration especially with the exciting launch and deployment with James Webb, and the data that’s going to bring will be very complementary to that.

Host: Let’s dig into DAVINCI details.

Sekerak: The DAVINCI flight system is a really, really exciting engineering endeavor. We call it the flight system, which is the part that goes into space but it’s actually two separate components. The flight part of it, the flight system, is composed of the Carrier Relay Imaging Spacecraft, or CRIS — that’s the spacecraft that takes the part that goes into the atmosphere. The part that goes into the atmosphere is called the Pro Flight System. And that Pro Flight System itself has two other components, which is the entry system to get the probe through the atmosphere and then the descent sphere itself, which is about a one-meter diameter titanium sphere that’s packed full of sensors that descends through the atmosphere and it takes all these really critical measurements of the Venus atmosphere.

Inside that one-meter diameter titanium sphere, we’ve got the Venus Mass Spectrometer, that’ll be looking at noble gases, as well as isotopes. We have the Venus Tunable Laser Spectrometer, which will be measuring water and oxygen and sulfur and phosphine. We have the Venus Atmosphere Structure Investigation. That’s going to be looking at the pressure and temperatures and the wind structure. It’ll help us understand what’s going on in the atmosphere physically. And then we have the Venus Descent Imager, and that’s going to be taking images below the clouds all the way down to the surface. And then finally on the descent sphere, we have the Venus Oxygen Fugacity, which is a student collaboration experiment to actually measure the partial pressure of oxygen. Within that, packed within that one-meter diameter sphere, we have these five instrument packages that’ll be collecting critical data that all get beamed up to the CRIS, the Carrier Relay Imaging Spacecraft that’s flying by Venus that’ll then beam that data back to Earth.

But oh wait, there’s more, because on CRIS, there’s also two instruments, which is the Venus Imaging System for Observational Reconnaissance that’ll be measuring ultraviolet and near infrared as well as CUVIS, which is a Compact Ultraviolet and Visible Imaging Spectrometer. So count them, seven payloads on a discovery class mission. Five going into the atmosphere and two onboard the spacecraft that’ll be taking images during our Venus gravity assists throughout the mission. There’s a lot of science that we’re going to be gathering both in situ chemistry, as well as remote sensing, all packed into the DAVINCI mission.

Host: Oh, wow. You can see why the science community is so excited about this mission. What’s the mission timeline?

Sekerak: We were selected in June of 2021 and our launch date is June 2, 2029. That’s eight years from selection to launch, a little bit longer than we prefer but with NASA budgeting at Headquarters they asked us to push off our launch date a little bit. We launch June 2, 2029, and our first Venus gravity assist is on January 17, 2030. And during that Venus gravity assist, we’ll be doing near infrared imaging of Alpha Regio. We’ll be getting some imaging of the target that we’ll be dropping the descent sphere off on a later flyby. We’ll also be getting some dayside ultraviolet imaging with VISOR and CUVIS. And so, we’ll be getting a lot of data shortly after launch, which is very unusual for a planetary science mission. Within six months, we’ll be getting level one science being beamed back to Earth.

On Venus gravity assist number two, flyby number two, on November 15, 2030, we’re going to do near infrared imaging of four other tesserae as well as more ultraviolet dayside imaging. And then finally on June 22, 2031, during the Venus gravity assist number three, during that flyby, is when we’ll drop off the pro flight system, which will then go into the atmosphere and then release that descent sphere, that’ll continue all the way down to the surface of Venus.

Host: At this stage in development of the mission, what are you focused on?

Sekerak: After selection, we’re formally in Phase B, and in NASA parlance, Phase B is part of the preliminary design phase, the formulation phase. And so, we’re doing all of our preliminary design work leading up to a preliminary design review in 2025. And so, the way NASA does their missions, we have two different rounds of design reviews before we actually go into build and fabricate, assemble and test the flight hardware and launch it. We’re doing a preliminary design review in 2025.

A lot of the time we’re focusing on right now is we’re building up our team. As I mentioned, we have seven different payloads on board the spacecraft. We have a large number of partners that we are teaming up with for this mission all across the country. We’re putting the leaders in place and putting the leadership structure in place for how we’re going to do this development.

We’re also doing a lot of requirements development right now. We’re solidifying what we call the level one requirements. And what those are is the primary science requirements of we’re signing an agreement essentially with NASA Headquarters of these are the science that we will deliver. We formalize that, what’s called the program level requirements appendix and that basically tells Science Headquarters, these are the science measurements that we are going to get and how we’ll advance the planetary science. And so, we’re developing those right now.

And just to kind of give you an example for how that process works, let’s say we want to understand those atmospheric sources and losses and that atmospheric formation evolution process. Well, to do that, we need to take atmospheric samples and measure isotopic ratios of noble gases to a certain level of precision. And from that, we then determine that we need the Venus Mass Spectrometer. And that’s how we derive a lot of the lower-level requirements and lower-level design details. That’s how we build requirements flow-down, so we know what to build at the lowest level. And so that’s what we’re working on right now as well as we’re doing some risk reduction by looking at what we think are the biggest technical challenges that may pose schedule or cost risks and putting upfront resources there to try to buy those down is what we’re working at this point in the mission.

Host: What do you see as the major engineering challenges?

Sekerak: Well, one of the major engineering challenges that we have is that the descent sequence is a one-time-only event and the data collected by the descent sphere has to be successfully transmitted to the spacecraft and relayed to Earth for us to get this exciting in situ data that the DAVINCI descent sphere is going to acquire. And so that descent sequence is very carefully designed and will be a thoroughly tested series of events for the descent sphere. It’ll be approximately one-hour descent through the Venusian atmosphere.

First, the Pro Flight System separates from CRIS, which is that carrier relay spacecraft, about two days before the descent in the atmosphere. And CRIS is constantly tracking it with the two-meter high gain antenna using a two-way S-band link. And then entry begins at about 145 kilometers, which is what we call the atmospheric entry interface, where there’s a blackout period due to the plasma. And then the pilot chute deploys, pulls off the back shell and pulls the descent sphere out of the thermal protection system, which is the protective shield that gets it through the atmosphere, and the main chute is deployed. At that point, the descent sphere is descending through the atmosphere on the main parachute. And there we open up ingestion ports that allows descent sphere to actually bring in some of the Venus atmosphere inside the instruments, inside VTLS and VMS in the atmosphere that allows them to take those critical spectrometer measurements. And it does continue to take those throughout the entire descent.

About 32 minutes after atmospheric entry at about 38 kilometers above the surface is when the main chute separates and we start our terminal descent down to the Venus surface. At that point, VenDI camera is acquiring images below the clouds all the way down to touchdown. Now you may think that we’re just falling, but don’t think of it the same way as on Earth. Because of the thickness of the atmosphere, the descent sphere going through that thick atmosphere, well, it’s more like a pebble falling down through a pond than it is what you would picture on Earth. And then we go down and touch the Venus surface.

Now we don’t have a requirement to survive on the surface after touchdown but there’s nothing that says that we won’t. And if we do, we can continue transmitting data for some short period of time afterwards until the spacecraft is over the horizon. So, those are some of the major engineering challenges that we’re facing with that the descent , but our team I know is up to the task for us to design and test and execute this complex mission.

Host: And we had a privilege of chatting with you back in October about the Lucy mission — and congratulations on the successful launch of that mission.

Sekerak: Thank you very much. The launch on October 16 of 2021, it was an amazing experience and we are so excited that Lucy is on her way and all the instruments have checked out. Fantastic. And we’re looking forward to a lot of those asteroid encounters. What’s interesting is Lucy from launch to when we do the first Trojan encounters is about six years, but with DAVINCI, from launch to the first science from Venus flyby, it’s only six months. Very different time scales for missions.

Host: Oh, for sure. Are there lessons learned from your recent involvement with Lucy or other NASA missions that are coming into play with the DAVINCI mission?

Sekerak: Oh, definitely. One of the things that’s already helped us in the planning process in a lot of the Lucy team members who will also be moving over to DAVINCI is that the Trojan asteroid flybys, they’re also single opportunity events. Even though we are for Lucy are flying by multiple Trojan asteroids, each one we only get one chance at it so we have to get that right for that encounter sequence to actually get the proper images of the asteroid. And it’s a similar type of philosophy that I was describing with the descent sphere that we only have one chance. With Lucy, we created special tests and we developed certain development products and other documentation to make sure that we were successful since we don’t get a second chance. And that mentality and those processes and the idea of those special tests and special personnel designed to lead those special unique events will help us as we go forward in planning DAVINCI and its one-time-only events as well.

Host: Well Mike, with NASA gearing up for a pair of Venus missions, does the DAVINCI team coordinate or work with the VERITAS team?

Sekerak: Oh, certainly. We were really excited that in that announcement in June, that the VERITAS mission led by JPL was also selected. There’s a lot of complementary science that we’re going to get from what they’re doing for their mapping, as well as our in situ measurements. We are already starting to work with them and setting up special meetings where we look at synergy, both from the science standpoint as well as the engineering standpoint. So, we’ll definitely be working together and excited to be teaming up with them.

But also, NASA’s collaborating on the ESA mission EnVision that was also selected. And now while both VERITAS and EnVision are orders with radar payloads, DAVINCI is the only one that will enter the atmosphere, but all three of missions will provide a lot of great new data on Venus. And I think we’re really entering an exciting age of Venus exploration with all three of these missions going off at approximately the same time. And so, the Venus science community’s been asking for this for years. And their patience is definitely going to pay off with what all three of these missions working together are going to bring.

Host: And the DAVINCI mission also includes technology demonstration. Could you fill us in?

Sekerak: Yeah, it’s actually two different unique payloads of those seven that I think are worth discussing for its uniqueness. And that is the Compact Ultraviolet to Visible Image Spectrometer, or CUVIS, is a spectrometer, which are typically large and very expensive and complicated instruments. But with CUVIS, we’re going to use freeform optics as well as artificial intelligence for onboard data reduction that really should allow simplification and shrinking of the spectrometers to be used on possibly smaller spacecraft. This really is a groundbreaking spectrometer, a technology demonstration for what it could mean for spectrometers on future missions.

But we also have a student collaboration experiment, which is the Venus Oxygen Fugacity and that’s going to be a sensor that’s designed and built by college students that’s going to be on the exterior surface of the descent sphere that’ll measure the partial pressure of oxygen during descent, which is going to be a great opportunity for outreach and to help build the next round of planetary scientists, as well as planetary engineers.

Host: What attracted you to the DAVINCI mission?

Sekerak: Well, planetary missions are my passion, which is why I sought out the Lucy mission as well as set out the DAVINCI mission when those engineering opportunities came up. And DAVINCI’s not only going to another planet but it’s going to smell and taste the Venus atmosphere while collecting more images of the Venus surface than all other missions combined. And so, if that doesn’t get you excited as a planetary mission designer, nothing will. But also, the technical challenges, operating in that harsh Venus environment that I described with the pressure, the temperature and the sulfuric acid clouds is an engineering challenge that’s really exciting to jump into. As well as the ability to look up in the night sky and say, ‘That’s where we’re going next.’ Since Venus is the brightest obvious and night sky after the Moon, you look at it, point at it and say, ‘We’re going there.’

But really most of these missions are about the team and the opportunity to work with so many partners that we have worked with before, including Lockheed Martin, JPL, APL, NASA Langley, NASA Ames, Kinetics, Malin Space Science Systems and University of Michigan, which is where I did my Ph.D. Really excited to have all these members on one team together. And it’s the passionate and the talented team of people that we’re putting together to make these amazing missions happen. And I’m really proud being the engineering lead of this group.

Host: Getting to be part of this team and passion that you have for these kinds of missions, did you get to be part of selecting the name for the mission?

Sekerak: Well, so DAVINCI actually went through two different rounds. The first round of the discovery, the competed discovery missions, DAVINCI narrowly lost out to Lucy in the 2017 selection from the 2014 discovery round that were selected in 2017. And so that’s when the name was originated and then it was so close to being selected that we then resubmitted it for this discovery round and it was ultimately selected with VERITAS. I didn’t get to select it. But our Principal Investigator, Jim Garvin, who is well known within the planetary science community — one of his idols is Leonardo da Vinci. And so, he had a hand in naming that for that famous Renaissance artist.

Host: Oh, that’s fun. This has been enjoyable talking with you today. I really do appreciate you being on the show, Mike. Thank you so much.

Sekerak: Happy to be here and looking forward to being able to provide updates as we develop this exciting mission to Venus.

Host: Are there any closing thoughts?

Sekerak: Just look up in the night sky and say, ‘Venus, we’re coming for you.’

Host: And you can learn more about the Venus missions via links on our website at APPEL.NASA.gov/podcast. Mike’s bio and a show transcript are also available.

In the second part of our Venus series, we’ll shift our attention to the VERITAS mission and chat with Project Systems Engineer John Brophy. That episode is set to drop Wednesday, February 9, and we’ll look forward to connecting with you then. In the meantime, if you have ideas for future guests and topics, please let us know on Twitter at NASA _APPEL – that’s APP-EL – and use the hashtag Small Steps Giant Leaps.

As always, thanks for listening.