Transcript: Space4U podcast, Sarah Noble

Written by: Space Foundation Editorial Team

Hello, this is Andrew de Naray with the Space Foundation. And you’re listening to the Space4U podcast. Space4U is designed to tell the stories of the amazing people who make today’s space exploration possible. Our guest today is Dr. Sarah Noble. Sarah is a planetary geologist at NASA headquarters in Washington, DC, and she is currently the program scientist for the Psyche mission, which is what we’ll be talking about today.


Sarah earned her Bachelor of Science in geology from the University of Minnesota, and then her Master of Science and PhD in geological sciences from Brown University. After graduating, she worked as a congressional staffer with the United States House Committee on Science Space and Technology, and then went on to serve as a NASA postdoctoral fellow at the agency’s Johnson Space Center.


In 2008, she became a post-doctoral management fellow at NASA HQ. And later took a position as a research scientist at the University of Alabama in Huntsville and NASA’s Marshall Space Flight Center. From 2010 to 2014, Sarah split her time between NASA Goddard and NASA HQ, working on various research and program activities until 2014, when she began working at HQ full-time, she was the program scientist for NASA Lunar Atmosphere and Dust Environment Explorer spacecraft known by the acronym LADEE.


And from 2014 to 2017, she was the deputy program scientist for Mars 2020, since 2017, Sarah has been working on the Psyche mission and she is also currently the program scientists for the Volatiles Investigating Polar Exploration Rover acronym VIPER, and the Lunar Reconnaissance Orbiter also known by the acronym LRO.


Sarah sounds like you are a very busy person right now. Thank you so much for taking the time to join us today. I’m happy to be here. Before we get into questions. I’d just like to give a brief background on Psyche the asteroid for our listeners who may be unfamiliar 16 Psyche, the official name of the asteroid was discovered by Italian astronomer Annabale de Gasparis in 1852, and as indicated by the number and the name, it was only the 16th asteroid discovered.


Named after the Greek goddess of the soul, it measures about 140 miles in diameter. It resides in the solar system’s main asteroid belt between Mars and Jupiter. And it’s one of the most massive asteroids containing about 1% of the mass of the entire asteroid belt and having a surface area of more than 246,000 square miles.


Psyche is the only known object of its kind in the solar system. And it’s thought to be the exposed remnant core of a protoplanet meaning that it was likely a planet that began to form, but then lost its outer layers due to violent collisions that occurred billions of years ago. Unlike most asteroids that are rocky or icy bodies, it is believed that Psyche is composed mostly of iron and nickel, similar to the Earth’s core.


It’s been reported that Psyche is valued at 10,000 quadrillion dollars because of all that metal. That’s a lot of zeros. In fact, it’s more than the entire economy of our planet. The asteroid is located more than 300 million miles from Earth. So ironically, we’ll be traveling all that distance to learn more about the core of our very own planet.


And you’re the expert. Sarah did I, uh, Did I miss anything up there? Do you want to correct me on anything? No, that sounds, that sounds that’s pretty close. Um, yeah, it’s a, it’s a, it’s a cool, weird little place. Um, strangely, you know, metal, a metal world that we’ve never been to a metal world. We’ve been to worlds of rock.


We’ve been to worlds of ice, but we’ve never been to one that’s made out of metal, which is weird and cool. And, and it’s going to be exciting. So could you tell us how you first got involved with the project and why you’re passionate about it? So I’m the program scientist for Psyche, which means that I’m the headquarters person.


My role at headquarters is sort of to be the champion for the mission at headquarters, to make sure that it has, uh, has a voice there. Um, and also to make sure that the mission is, is doing all the things that they said they were going to do when, when NASA gave them the money to do it. And so, so I sort of sit at both sides of that.


I am there to, to make sure that. But the mission has everything they need, but also that they’re doing what they suppose they’re supposed to do, which is a, it’s a fun place to be, you know, let’s me to sort of see, see everything that’s going on from sort of a high level, uh, and make sure that that everything works out.


What phase is the mission currently in? Can you kind of describe what aspects are being focused on right now? So they just passed in May. They passed their KDPC, which is. Spacecraft language right there, there are different stages of a, of a mission. A phase a is, you know, we wrote a proposal and here’s an idea.


Um, phase B is the sort of mission. Design phase where they, you know, work through the, the complications and make sure everything is actually gonna work the way that they thought it did. And a, and then C is, is the building phase, right? We’ve got the designs solidified. Now we know how everything works.


And then C is the phase where you’re actually building hardware. And so they’re working really hard right now to actually build the hardware. And then D and D is, is the actual flying of the mission so that they’re getting there. Um, you know, this is the part where the rubber really hits the road and the, and they have to like buckle down and get all the pieces to fit together.


And so, uh, it is challenging. It’s extra challenging right now doing it in the middle of a pandemic. They’re having their meetings from Zoom and, you know, trying to, trying to get into the lab, uh, get exceptions so they can get into lab and, and, and build things and do their tests. And, and it’s. Uh, it’s a challenge, but they are, they are meeting it.


Uh, it’s an amazing, it’s an amazing team. And it’s sounds like there are people working both at NASA HQ, such as yourself and JPL. And then there’s also a team at ASU, Arizona State University. Uh, how large is the total team working on the mission? Ah, oh, it’s hundreds of people. So, this is a, this is in, in the planetary science world.


We have different kinds of missions. This is actually a PI led mission. A principal investigator led mission. And so the person who proposed it Lindy Elkins-Tanton, who is the PI of this mission, uh, is in Arizona. So she proposed this mission to NASA and said, you know, I want to, I want to do this mission along with lots of other people.


Uh, was a big competition and those proposals were reviewed by peer scientists and engineers. Uh, and she won. Um, so she gets to do her mission. Uh, and so she’s the leader of the mission at out of ASU in the mission is being built largely, um, at JPL. As well as the Jet Propulsion Lab in California, as well as a Maxar, which is, uh, which is a company that builds a lot of satellites.


They’ve got, you know, they’ve got like an assembly line of satellites. It’s an incredible place to go visit, um, mostly commercial, like, you know, XM Radio, whatever, those, those sorts of satellites. This is the first time they’re building a spacecraft for us, for NASA. And it’s kind of a great, wonderful little partnership for them to do this like deep space mission.


They’ve never left Earth orbit before. So, uh, so they’re excited. We’re excited to work with them. And then we’ve got a lot of, you know, besides the engineers, we’ve got a lot of scientists, uh, you know, the folks at ASU, but also we have scientists, uh, in many other institutions. Building the various instruments that are, that are going on the spacecraft as well.


And so we’re sort of spread out all over the, all over the country and even the world, our magnetometer is actually coming from Denmark. So well. Yeah. So the original launch date was set for 2023, but it’s been moved up to summer 2022 last I’d heard. Why did that happen? And is that creating any challenges for you guys?


So the launch date is actually a really interesting story. Uh, it was originally proposed to launch, I think in ‘21 when the, in the original proposal when they proposed. Uh, but we selected two missions in that round of selections, uh, Psyche, but also Lucy, uh, and Lucy is also launching. In 2021 and we couldn’t fit both of them together.


So we asked the team to move their launch date to ‘23 and they had, but they did some work on that and found actually a launch date in ‘22 that gets them to Psyche faster than the launch date. And because orbital mechanics are fun, you know, so it was a much more favorable launch in 2022. And so we’ve decided to go into that instead.


And, uh, yeah, I, orbital mechanics are amazing. I don’t really understand it’s all black box to me, but like it’s, it’s so cool. Like the ‘23 launch, I think they had to sort of hang out around Earth for awhile before they headed out into the asteroid belt, and this is a more direct path. And so it actually actually ends up getting them there slightly faster.


So the spacecraft is not going to land on the asteroid, correct? No. Okay. You’re going to, why do we suspect we already know the composition of the asteroid? Like how did we detect that from 311 million miles away? Yes. So we have data from ground-based telescopes. That’s can look at it’s it’s, reflectance how, how it reflects light.


And it’s, it’s pretty bright. We can get estimates of its density, but it’s, it’s hard to do these things. And so our estimates have been changing actually of what we think it’s made out of when they proposed this mission. You know, years ago we thought it was probably 90% metal, and now we think it’s more like 30 to 60% metal.


So, you know, we’re, we’re continuing and, and now, you know, once the mission was selected, a lot more people have been looking at it, tell us topically and trying to understand more about it. And so we’ve gotten a lot more data. Uh, and so our, our understanding of it is evolving. But there’s only so much you can do from that distance and where we are going to have to get there before we can really understand what’s going on.


You know, there are tradeoffs in between, you know, metal is heavy, it’s dense, right. But we don’t know how much porosity there is, how many cracks and how, how far apart, different particles, parts of the thing are. And so, so you can have a lot of empty space, uh, in amongst the metal, right. Which would make it look lighter, or you could have.


You know, a lot of lighter materials, right? And so understanding that from a distance is a real challenge. And so a lot of that is going to have to wait until we get there. But the good news is we’re going and we are going to be able to, to have answers to these things in a few years. And I understand there are very few pictures of the asteroid, like maybe a low-res picture from Hubble, but I’ve seen some artists rendered pictures of it though.


So how do we know about its appearance? Yeah. Most of our imagery of it is actually radar imagery. So Arecibo has looked at it. I think maybe another radar anyway, and see, you get very sort of pixelated and you get these sort of reflections and you have to interpret them. And, you know, two people can look at the same radar image and come up with a sort of different interpretations, but we have a general idea of its shape.


And we think we see, uh, you know, if you see the renderings of it, there’s always these two big craters, uh, in the, in all the renderings. We think those are probably real. They’re hinted at, in the, in the radar data. And so, and so we have some vague understanding of the general shape from radar, but the rest of it is, is all sort of artists, uh, imagination, you know, and I guarantee it won’t look like that when we get there, but it’s fun to think about it.


Like what will it look like? Um, and we’re actually we’re planning, um, like a big worldwide art contest to get kids or adults or whoever to paint or sculpt or draw or make it out of Legos or whatever, however you want to do it. So what you think Psyche is going to look like when we get there. Uh, we’ll give an award, I don’t know, probably not prizes, but, you know, at least kudos to whoever gets closest when we actually get there. Well, that’s really cool. Yeah. Get people involved. So I’m going to show my own ignorance here, but since we can’t get down there, how do we actually know what the Earth’s core is composed of? So we have a lot of size monitors on Earth, right?


So that we can get the sort of structure of what we think things are. And that will tell us some things about density. And, and then we can make assumptions about what, you know, what we think the composition of the Earth is made out of and what that has to be. So we understand the physics of how, when you have a, you know, a molten body like the Earth, the iron is heavy and it will sink down to the middle.


So we have a sort of understanding, and we know what comes along with that. And we know that oftentimes nickel and sulfur and these things will come along with those elements. And so we have a general idea and then we can get some specifics based on. Seismic networks and what the structure of the internal of the Earth does when, when seismic waves go through it.


I’m not a seismologist but, but, uh, but you can learn a lot from the interior that you can’t see based on that. So, uh, I guess it follows then just with planetary formation, that, that then Psyche would have the same composition as the Earth’s core. If it is in fact a core. Yes, that that is what we think that is our sort of going in hypothesis for what Psyche is, is that it was part of a, you know, a larger proto-planetary body and that the rock parts got sort of stripped off in, in a number of impacts and what’s left is mostly the core.


And so that is the main thing that we’re going to go and test. So we’ve got a magnetometer which will tell us if it has a magnetic field and our planet, right. Generates a magnetic field because of its core. And if Psyche at one time had a magnetic field that would be trapped in the rocks and we’ll be able to measure it with the magnetometer.


But even if it doesn’t, that doesn’t necessarily mean it isn’t a core. It just means that, you know, maybe it didn’t generate a field or that field has been disrupted. So that’s not definitive. If we find a magnetic field that is definitive, but if we don’t, that’s not, that doesn’t necessarily mean it wasn’t a core.


So we’re also measuring, uh, we’ve got a neutron and gamma ray spectrometer that will measure the elements. So it we’ll be able to see how much iron, how much nickel, sulphur, you know, and silica and calcium and aluminum and all the major elements and see how much is there. And then we’ve also got, um, spectrometer, uh, we got, uh, imagers that have that look at different wavelengths so we can get spectrum.


Right. Well, tell us about the mineralogy, not just the chemistry, but also the mineralogy. And so, uh, so we’ve got this suite of instruments that is going to give us a sort of picture of what is there from that we can figure out mostly by comparing to, uh, meteorites that we have here on Earth. What kind of asteroid we think it is.


And then let’s shift to the spacecraft. They’ll be going there. How large is it? Like what’s the size comparable to, uh, with its solar panels. It’s like the size of a tennis court. Cool. Talking a little bit about the instruments on there. If we want to elaborate on that, like, well, there’ll be, we’ll be providing like images, photos, or video.


Yes, it’s got, it’s got actually two cameras. They’re both the same, but we like to have redundant systems just in case one doesn’t work, whatever. So we’ve got two cameras that will look in different wavelengths of light so we can get a picture and we will take pictures. Well, we have several different sort of orbits plan.


The first one is pretty high out and then they sort of go in and we get, so we’ll get different levels of detail as we get in closer and closer. And in any video or just still photos, just stuff about us. Okay. And then, uh, what route will the spacecraft retake in to reach Psyche? And how long will it take to get there?


I said flies by Mars. Got a little flyby Mars to get a little boost from, from Mars. Uh, it has ion engines which are very efficient, but not super-fast. So it takes a little time to build up the momentum, to get them, to get them going. Um, and so it takes about four years for us to get there, which is, you know, in, in planetary business, you have to have patience.


Yeah. It’s not instantaneous to get there. So yeah, we asked her, we’re going to take about four years. I did get to editing it, but takes about a year to get to Mars and then another three, uh, to get out to the asteroid. And then we’ll orbit the asteroid for two-ish years. I think. Is it going to have any objectives when it does the flyby of Mars?


Well, we will use it. Yeah. They’re not objectives to really study Mars, but it was a great opportunity to test out all the instruments and like actually take pictures of something, right. And not just empty space, whatever. And so, so all the instruments will, it will have an opportunity to start test themselves, make sure all of their systems are running, make sure that we understand how to get the data, how to calibrate the data, how to get the data into our data systems.


And so it’ll be a great sort of test run for, for all that. As they are on their way out. The, uh, the other thing that it has on it is a technology demonstration called do you space optical communications, which is testing out optical communications, right? So instead of, instead of using radio bands or, you know, expands in the other frequencies that we normally communicate with, you can use optical, just like we use optical fibers here, here on Earth, and it’s super blazing fast.


Right? You can, you can do that from space too. And so this is the first. So deep space, we have done this. We actually did this on LADEE. The other, the mission that I was on a few years ago, we tested out optical communications between the Earth and Moon. Uh, this is the first time we’re going to test it out in deep space.


And so on our way out to Mars, uh, we will be testing out this deep space communications to try and figure out how, how fast it is. You know, it’s like, hundreds of times faster than the normal communications. And so if we can get that to work, we can get, you know, much bigger and better data sets back from the Moon, from Mars.


So we’re, we’re testing out this technology and Psyche has been generous enough to, to let us test out this technology on their mission. So it has nothing, you know, it’s not, it’s not sending data from Psyche. It’s not connected to the mission itself, but we are, we are using it to test it out for future missions so that we can, we can get back all the data.


Well, that’s awesome that it’s for other missions too. That’s great. And you touched a little bit on the propulsion. Is there kind of a low-level way of explaining how exactly that works? Yeah, so basically IM Propulsion it’s, um, ejects, Xenon, so we’ve got Xenon gas and ejects, the Xenon gas. And it creates just a tiny amount of impulse that over and over again.


Right. It’s like the, it’s the amount of impulsive, like the weight of a piece of paper, right? Like, it’s just nothing. But if you keep doing that over and over again, you build up speed. And so if you’re going a long way, All right. And the engines are really efficient. It takes very little Xenon. Doesn’t weigh very much.


Uh, it takes very, very fuel efficient, and you can eventually build those speed. It just takes a while. Right. And so it starts out slow, but if you pick up the pace and, and so that’s a cool little way to, to get places. I don’t know me. And so reaching the asteroid in 2026. So, and then how long will it be actually analyzing Psyche?


So I think it’s about two years is our, our sort of nominal mission. Uh, and like I said, there’ll be the different orbits, different, different instruments want to be at different distances above the surface. So, you know, the higher orbit is actually better for the imager that can get better imagery. Uh, but they’ll particularly the neutron and gamma ray spectrometer is want to be absolutely as close to the surface as possible, um, so that they can pick up those neutrons and gamma rays coming off the surface.


And so we sort of choose these different levels to optimize for each of the different instruments. So it’ll be different phases kind of for each part of that. Yeah. Cool. So I, I understand that your personal area of expertise is space weathering processes. Yeah. So that’s not my job. Yeah. Um, and from a science perspective, I, you know, I, I’m sort of an observer on this mission.


I’m not one of the science team members, but I am. I, you know, I bring with it, my, my science background and I am very excited. Um, just to understand how face weathering works on a metal body. Again, we’d have no idea. We’ve never really seen what these metal bodies do. So you know what a craters look like on a, on a body made of metal, um, you know, how does the iron …  what happens to the iron when you hit it with micrometeorites and you hit it with solar wind?


We don’t have a clue. And so I, I’m personally very excited about, about the science that Psyche is going to do, even in my little niche field. Um, let alone what, what the team is excited about, about it too. But yeah, it’s cool. I, you know, like I said, we’ve never been to a metal body before and you know, we’re, we’re doing our best.


We we’ve done some practice things in the lab. We’ve actually, we have, um, these guns. Literally guns that you can fire projectiles. And so we have like, you know, fired projectiles into metal meteroites and, and, you know, pieces of metal to try and understand what you know, but that’s a very small scale, you know, we’re, we’re making things that are, you know, maybe an inch across and…


Yeah. You know, those giant craters on Psyche or, you know, dozens of miles at least. And so, you know that you can’t really scale from one to the other. Um, so we’re doing our best to try to understand, but until we get there, I think we’re just not gonna, we’re not going to know. So you’re actually shooting projectiles at it to see like how it reacts the surface reacts.


Yeah. Yeah. We’re making little, we’re making little tiny craters, a little, you know, like, like an inch or two inches across, right? Yeah. Um, it’s really cool. They don’t, you know, it doesn’t look like craters into, into a rock or craters into soil sand. Um, they’re, they’re very different. They’re very different and very cool.


It sort of freezes in place. The, the metal sort of melts and then freezes and place in you. You get these little shapes and yeah. But does that happen when it’s, you know, 50 miles across instead of an inch find out, I guess we’re going to find out. So, so being that the spacecraft’s going to be in the asteroid belt, are there any threats to the spacecraft while it’s there?


Despite what you see in the movies, the asteroid belt… I mean, there’s a lot of stuff there, but there’s a lot of space, so, no, I mean, we’re not going to see another asteroid probably on our, on our way out. Uh, just like things were pretty. Pretty far apart, not that densely populated out there. There was, you know, recently the very publicized the Cyrus Rex landing, and a sampling of the Bennu asteroid.


With Psyche, why are we not trying to land and collect samples? Um, I mean, that’s a whole, that’s a whole different mission, right? Uh, so again, this is a, this is a PI-led mission. So, you know, Lindy wrote a proposal and this is what her proposal was to do. Right? The mission category discovery mission that she is in has a cost cap.


You can only spend so much, right. And so you try and maximize the amount of science that you can get within that cost cap and, and actually landing on a surface. Would probably blow that cost cap way on the out of the water. The Osiris-Rex mission, uh, is not a discovery mission. It’s, it’s a bigger category.


It’s a New Frontiers class mission, which is the next category up. And so I’d more expensive, still, totally worth doing. It’s an, that’s an amazing, cool mission, but we think that we can learn what we want to learn about Psyche without sampling it. And so we, you know, we’re doing the right mission for this asteroid.


Cool. I guess if it’s super interesting you can go back. Yeah. Right. So will the spacecraft returned to Earth after it’s done collecting data? There was no, there was no reason to, right. We’re not, we’re not bringing sample back. So I’m just thinking about it. We just want the data.


So how daunting is this mission? Would you say? How confident is the team? Are there any concerns or anything? The team is amazing and the engineers are incredibly competent. I, I have no concerns about them achieving their mission, but it is weird and scary to go to a place that you don’t know. You don’t know what it is.


You don’t know what it’s going to look like. You don’t know what hazards you might find. You know, the Osiris-Rex mission. For example, right. Was expecting to find a place that was covered in soil, in, you know, fine grain material. And instead they wound up at a place that was all covered in rocks and that’s not what they designed their soil collection mechanism for.


Right. And so that was scary. And also it turned out that the asteroid occasionally spits rocks out. See that was not something they were expecting either. And it was a little dangerous when you have a delicate spacecraft that you are trying to get. Close to the asteroid. And so, uh, so I think anytime we go somewhere new, somewhere, unknown challenges and unexpected things, but that’s also great for science.


We’re going to learn so much from those unexpected things. And I think the team is prepared for just about any eventuality. So in your opinion, what would be the best possible outcomes or results from the mission? We’re going to get great science. Um, we’re gonna figure out is Psyche a core? Is it not a core?


I actually think if we go there and it’s not at all what we expect and plan for that, that’s even more exciting if everybody was wrong about it, like that’s the coolest and the way that we learned the most and can keep moving forward. It’s boring. If it turns out exactly to be exactly what you expect.


That’s cool outlook. So I mentioned earlier that Psyche was the 16th asteroid discovered, but I understand that five years ago, and asteroid was named 133432 Sarah Noble in your honor. Could you tell us about how that happened? Yeah. Isn’t that? Isn’t that the coolest thing, right? Yeah. Uh, so there’s a lot of asteroids out there.


I mean, I don’t want to play it down because it’s super cool and amazing, but it’s not that difficult to get an asteroid named after you, whoever finds the asteroids gets to name them. And so, uh, I have a number of colleagues. That are asteroid hunters that find asteroids. And it is, it is, um, tradition to name them after people who study asteroids or they sciences.


Um, and so I was, I was lucky enough to be honored with one, a little bit longer of a number to remember 16 is a little easier, but, 133432?


In addition to your scientific side, I’ve heard that you’re also a painter. Could you tell us about some of your favorite artworks that you’ve done in your inspiration behind them? Uh, yes. I I’ve been painting for a very long time. I think, uh, sometimes it is. It is easier to express my love for the solar system through paint than it is through words.


And so a lot of my paintings do you focus on, on the Moon? My personal favorite, but also, uh, other planets, uh, and exploration in general. I think science and art people are often surprised to hear that a scientist is also an artist, but there’s actually a lot of us. And it turns out that they’re really the same.


They’re both just creative problem solving. And so I very much enjoy that. And it’s one of the things that I have. I really loved about the Psyche mission in particular is RPI has been a big proponent of making sure that art is included in this mission in a lot of ways. So we have, in addition to sort of traditional science interns, we actually have art interns on Psyche who are amazing.


We get a new class of undergrads every year who come in and, uh, listen to us and learn from us and are inspired by the mission and do art relating to the, to the mission. It’s it’s a fantastic, uh, Psyche inspires, go, go, go and follow them online. There there’s some beautiful, amazing artwork of all kinds of, you know, traditional sort of painting and sculpting or whatever.


But we also have, you know, jewelry making. We have music, we have ceramics. You have. dance, we ha you know, you name it. Somebody is making Psyche art about it, which is so cool. I really enjoy that. And if you go to, um, psychespacecrafty, you can, you can submit your own artwork. If you are inspired. If anybody out there is inspired by, by the mission and or the asteroid, um, you can submit your own artwork to the, to the site.


And, and we have a little gallery there. Um, that actually has quite a few of my, of my artistic works in there as well, because I think this, this mission inspires me every day. So, uh, so anyway, so there’s ways to, to participate and art is just woven through the whole mission, which is awesome. That is, that is great.


I think that about covers my questions. Were there any other thoughts you have about the mission or anything else you wanted to share about it? I have to say I have loved working on this mission. Of all the missions I have worked on. This so far is my favorite. And it’s mostly because of the team of people who are involved in this mission.


It is, you know, hundreds of people, as I said, but like, you know, really amazing people who are working hard together and staying connected through what is a really horrible and difficult time. And they’re doing just fantastic work. That’s great. Well, Sarah, again, thank you so much for you your time today, we are really excited about this mission and we appreciate you filling us in on all these awesome details.


And, uh, that concludes this episode of the Space Foundation’s Space4U podcast. You can subscribe to this podcast and leave us a review on Podbean, Apple Music, and on Google Podcasts. Don’t forget to follow us on Facebook, Twitter, Instagram, and LinkedIn. And of course, our website, where you can also learn about the various ways you can support the Space Foundation. On all of these outlets and more it’s our goal to inspire, educate, connect, and advocate for the space community because at the Space Foundation, we will always have space for you.


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Space4U Podcast: Sarah Noble – NASA Program Scientist, Psyche Mission