Image credit: Myah Jeffers
In this episode, Divya Persaud explores creative approaches to studying planetary surfaces and the ethical challenges of space technology.
Episode Transcript
Marissa Lo: Hello and welcome to Geo Conversations, a podcast interview by Geoscientist magazine. My name is Marisa Lo and I’m the Associate Editor of Geoscientist and today I’m joined by Dr Divya Persaud, a planetary geologist and research fellow at the University of Glasgow. Throughout her research, Divya has worked on several different planets and moons across our Solar System. She’s also a science communicator, composer, and poet, something that I hope to talk about more in this interview. Can you tell us about your background in planetary geology?
Divya Persaud: My background is a bit mixed. I started out doing various things in remote sensing before university. And during university, I was really lucky to do some research programs that were teaching me how to do data analysis coming down from satellites, whether they were studying the Earth or other planets. I was also involved in some palaeomagnetism, which means studying how rocks record magnetic fields. So, I learned a bit about meteorites and other sorts of materials that might record magnetic fields. I got my hands on whatever I could at the time because I was interested in everything about space, everything about Earth science, as so anyone who said yes to me, I would just do whatever they asked. So, I did a lot of laboratory assistance. And what emerged from that was an interest in any way that we can use creative means to understand the surfaces, planets, and moons. And that’s a very general topic because it’s still really general to me. I still say yes to anything that comes my way.
But I got really interested in how we can use images, especially to study the icy moons of our Solar System. So that’s the moons of Saturn, Jupiter, but also small bodies like Ceres and Pluto. I was really interested in how we can use 3D imaging as well, so finding cool ways to combine images to reconstruct surfaces in three dimensions and the cool things that we can do with that. So, everything from, like, outreach with kids, the types of games you can make with these cool images, to doing some creative analysis as geologists, how can we sort of push the envelope of how we study, say, the surface of Mars using imaging techniques in a new way? And that was the focus of my PhD, was doing that sort of creating an immersive experience for me as a geologist to study the history of a small area on Mars. My long journey has really just been pulling at different strings of what’s sort of understudied, maybe. So that’s taken me everywhere. I did research at a few NASA centres in the US and then I did my PhD here in the UK and then went back to the US and then for my postdoc and then came back here. But kind of just saying yes to everything has been, been the guiding light in my career.
Marissa Lo: For lots of the objects in the Solar System, from what I understand, we usually just have 2D pictures of their surfaces. How do you then turn that into a 3D model?
Divya Persaud: The answer comes down to our own biology. The way we perceive the world in three dimensions is through our senses. And very cleverly, evolution has given us two eyes and even two ears. So, anything that we look at with our eyes or here with our ears, we’re looking at the same point in space but from slightly different angles between our eyes. And what our brain does with those two different images is it understands things like light and space and distance, and using that understanding, and the two images can calculate basically depth. So, our brain is a really high-powered computer. We don’t have to think constantly about depth when we look at things. It can just do that automatically. And it allows us to walk or understand the direction a sound is coming from.
And on the computer science end, it’s actually modelled on that. So, the idea that you have two images taken from slightly different angles can give you depth information. If we can understand the lighting, the space, other sort of factors about how a camera might be looking at the surface. So that could be a rover on the surface of Mars, which usually has a pair of cameras that act as the two eyes and gives you those two images, or a satellite where it looks at the same spot on two different orbits going from a different direction. And that way we can take those two images and then give them to computer programs that then for us do that nice calculation. And what it gives us at the end is an image that looks sort of just black and white. It’s sort of grey and murky, and every point is telling you the depth. So, if you put that image in software that understands, okay, instead of brightness, we’re looking at depth, this is a depth map. It’ll render it in three dimensions. And that’s really cool. So, if you’ve ever seen a 3D movie or you’ve more recently probably done VR, it’s the same exact principle. So, it might even be a VR software that you would put that in or something like VR that might just be on your computer screen and then you can manipulate the surface, you can fly over it, you can rotate it. This is really powerful because this really brings the surface of a planet to life.
Marissa Lo: You’ve gone from Earth to icy moons to Mars. What are you currently working on for your research fellowship?
Divya Persaud: I’m in a collaborative fellowship, which means that it’s an equal partnership with another research fellow. This is someone I’ve worked with during my PhD and he’s more on the engineering side of imaging and I’m on the more science side of imaging. So, we thought, what, what if we put that together and came up with an idea for a camera? So, the idea is that, say we look at Perseverance rover. We got fantastic images from Perseverance as it was landing, looking down at the Mars surface. And the cameras that tend to be on the bottom of rovers are there for engineering purposes, meaning that they’re there to help with the landing process. They’re there to help avoid hazards while landing, to navigate the rover to the surface. But there’s a lot of science that you can actually get out of those images because, say, for perseverance, the images were looking down. As it descends, you get sort of a lower resolution, more regional look of the surface over the landing site. And then as it gets closer, it gets higher resolution, but more localised. So, you’re getting quite a diverse look at the regional context that the rover is about to explore. And we thought, you know, what if we designed a camera that’s actually meant for science to go on whatever, whatever is landing? It could be a lander on Europa; it could be a rover on Mars. So, we’ve done a sort of experiment combining, we’ve, we have a drone, we took it out to a quarry nearby and have a prototype camera. We didn’t build it; it’s just a commercial camera. But trying to see, okay, what kind of data do you get out of this type of camera. I don’t know quite what the results will tell us. I think it is interesting. I think there’s some interesting trade-offs maybe when we think about what types of cameras are really good for science.
But right now, we’re moving into a new project. So, I described to you how you make a 3D image. It’s actually very difficult. And one of the issues that I’ve run into, a lot of people I know have run into, is that when you are at an icy moon, this is very different from Mars. So, Mars is like very red. It’s kind of Earth like in its surface appearance. But icy moons are super, super bright because they’re covered in water ice or carbon dioxide ice, usually a mix. They’re really, really, really bright. Any normal image of somewhere like Europa or Enceladus, it’s very smooth, it’s Very reflective. And when you make these 3D images from these surfaces, these are not spacecraft that have been orbiting and are collecting high resolution data. They’re usually just a flyby. You know, we have a dozen high resolution flybys of Enceladus ever, and we may not get more in the next 50 years. And the resolutions are different; the angle differences are very high. Making 3D images from that data is very difficult. And one thing that I’ve been wondering is how does the high reflectance of that surface actually impact it? If your camera’s being blown out by something really bright, like say you take a picture of the sky with your iPhone, how’s that actually affecting what’s happening on the computer end? Can it actually calculate the things that we want, or is it going to make mistakes? And this is something that no one has investigated before, but it’s kind of been lurking around for about 50 years, because every time one person makes a new 3D image of the same place as someone else 20 years ago, they have very different results. And we want to know why. So, we’re doing something really cool. My research partner has a software suite that can simulate images from any camera. So, you, you type in, like, what kind of camera you want. You give it like an input reference surface. So, for example, we might just put in the surface of Mars and then we tell it the altitude, we tell it where it’s pointing, and then it can actually produce the images. We thought, what if we actually use that to play around with a totally fabricated surface and make it reflective and change how reflective it is and then take out images from this hypothetical camera and then make 3D images from it. Then we can actually test out, okay, what’s affecting the quality of the resulting 3D image. So, it’s kind of in the weeds when it comes to methods, but it’s actually really important because Europa Clipper has just launched. And what Europa Clipper will give us, for the first time ever, is high resolution images of an icy body. The most important thing everyone wants is to turn those into 3D to study the texture of the surface of Europa. What does it tell us about water under the ice? What does it tell us about the history of the ice there? And we want to be prepared for that. We want to have this resource for the community to say, okay, this is a very sort of unique moon that we’re studying. This is the best way to process these images.
Marissa Lo: So, I know that you’re very passionate about space ethics in relation to space missions and space science. Can you tell people what are space ethics for people who’ve never heard of that term before?
Divya Persaud: Yeah, space ethics is a big term. It means a lot of things. Space ethics is broad in the sense that it deals with legal questions, with moral questions, with political questions. And it arose probably in the 1960s, really of the idea of human responsibility when it comes to space exploration. Things like the Outer Space Treaty of 1967, which tried to address at the United Nations, what is our responsibility as nations, as individuals, to stewarding space. How do we deal with the idea of weapons in space, for example? So, during the Cold War, this became an emerging use of space through missiles and satellites. The Outer Space Treaty attempted to legislate some of that to get countries to commit, okay, we will not use space for war, say, whoever lands on the moon first, whatever, they have to be responsible. You can’t claim territory in space, et cetera. Not all countries ratified this treaty, but space ethics has arisen out of this to address what are. What are our responsibilities? What are the ways that we can ensure that space is used for peace? How do we also act ethically as individuals in the space sector? How do we interface with society as the space sector? We have to ensure that there are regulations there to make sure that people stay safe. And that means everything from where a launch facility is. Does it violate indigenous rights, for example, or is dual use, which is a term that means technologies that have both civilian and military applications, which is most of space technology. How do we sort of legislate and regulate dual use technologies to make sure that people aren’t sneaking weapons into space, for example, or using satellites for surveillance purposes and other military uses? So that’s generally what space ethics is.
Marissa Lo: Where has your research or work in general overlapped and gone into space ethics?
Divya Persaud: The overlap is huge, but not in the sense of what I research. The overlap is in that everything that we do touches space ethics. But my own interest came out of it was just before university. I was reading some papers about space and how it influences politics. I was writing an essay for school, and I came across a lot of interesting work about French Guiana. So, I’m Guyanese. I’m from Guyana, which is neighbouring French Guiana. And French Guiana is still a department of France, so it’s still a colony. It is home to the Guiana Space Centre. Guyana Space Centre has seen a lot of protests from people in French Guiana for various reasons, but mainly it is a symbol of continued colonialism in French Guiana. And as recently as, I think 2018, there was a general Strike in French Guiana to pressure the French government to invest in the economy of French Guiana to build infrastructure. Things like roads, Internet. And the striking workers occupied Guiana Space Centre because it was such a symbol of this continued colonial control. And they won that, that strike, and they got millions of francs worth investment in infrastructure, which is amazing. There are whole books by someone named Peter Redfield. So, I read that at the beginning of my career, and I thought, oh my gosh, I didn’t realise this was next to my homeland. And that sort of stuck with me for a long time. And I started reading more and more about work of people like Redfield, space historians, sociologists, and learned a lot more about things like launch facilities that tend to infringe on indigenous rights. And I was reading also a lot of social and political theory at the time.
So, this has kind of been like a running interest of mine and became more of an interest as I learned. Oh, the, the companies that build our spacecraft also build weapons. So, as I mentioned, dual use. And dual use became kind of a fixation for me. Of all the missions that I’ve worked on have components built by companies that are, you know, arming various entities. So, I was thinking about, oh my gosh, you know, this is where my tax money is going. But also, I mean, they’re building my, this spacecraft to get my data. That’s what I mean. Like the overlap is 100% in that any data that I use coming from Mars, I know who built that camera and I know what else they built. So that became very troubling for me. And I started speaking out about this and I started talking to colleagues about this to try to understand why this was happening, why we sort of accept these relationships and the status quo in the field. So that’s been my journey with that. And I became involved more recently with the Palestine Space Institute, where now I actually research this. So, I’m a planetary geologist but also studying the economy of space militarism. So how, how do companies end up doing both of these things? Like what is the relationship here? Not just historically, but presently. That is like a parallel bit of research that I’m doing for people listening.
Marissa Lo: Now if they want to find out more about all the topics you’ve been talking about, what would your advice be to them?
Divya Persaud: Two resources. The first one, just Google “Space Ethics Library”. Actually, my friend Adeene [Denton] built this library with some other great people. And it is just loads and loads of articles, essays, research publications, any level that you want to read it, if you want to read it at the Academic level or just the introductory level. Really, really amazing resource. So, it gets into the law, the policy side, things like dual use. So, I would start there. The other resource I would point to a bit self-centred-ly is the report that Palestine Space Institute put out a year ago, which I wrote with them. And that is PalestineSpace.org/psi-database. So, this is a sort of a study that we did, an economic study in many ways of the companies that supply space activities. Wanted to see, okay, what space companies do we know also make weapons that are involved in the genocide in Gaza. And we identified 51 companies and basically list out what they produce for both of these things. And so, it’s really useful if you were coming from a science perspective to you can filter by missions that you’re interested in and see like, oh, actually this rover is connected to this military technology. And there’s a report with that that explains to a layperson the implications of all of that and gets into a bit of the history as well. So, I think that’s also a really good resource after you get introduced to space ethics, to kind of look at, okay, what is the state right now of the ethical problems in space?
Marissa Lo: Can you tell us how you’ve combined your planetary geology research with art?
Divya Persaud: So, for many years I did not think about my love of science in the same way I thought of my love of art. And I fought it, and I fought it. And then I realised, actually I really love making art about space. I’m really interested in my, in my writing and my poetry about place and memory. And this is where, you know, my background in geology comes in, because there are beautiful words in geology. It lends itself to poetry a lot. I write a lot about migration and my heritage with migration, including forced migration. I think a lot about the planetary travel that migrants take. I think a lot about sort of the memory that becomes embedded in land. And I think geology is just a beautiful way to think about it and to write about it. With my music, it’s kind of similar or the same. I’ll give you an example. Most recently, I did a little collaboration with a dancer who’s also a planetary geologist. My friend, Dr Adeene Denton was a resident astronomer at Grand Canyon National Park about a year ago. And they commissioned me to write some music to go along with the dance that they were going to do to close out their residency. So, I was just so moved by the poetics of this because my PhD was about a canyon on Mars, studying the layers of rock exposed in this canyon. And this is something that people love about Grand Canyon, right, is looking at all the layers. And I thought, I’m going to write a piece about these two canyons that are like sisters across two planets. And so, I wrote a piece about the formation of the canyon on Mars as well as Grand Canyon. So, the idea of sort of water trickling and then a braided stream and then a big storm and then just sort of slowly drying up. And I used cello, which I play, and then I recorded all sorts of sounds using, like, objects in my house and manipulation using, like, distortion and layering and stuff. It was a really, really fun experience. There’s a lot of music about space that tends to try to make space about being otherworldly or alien or strange. And we wanted to make something that made it feel like home and really honour that. We have a responsibility to steward Mars, to be ethical in that practice, and to understand Mars as nature, just as Grand Canyon is nature. And so, we wanted to have this sort of warm, inviting sound with familiar noises. Nothing that alienates you, because Grand Canyon is still home to Indigenous people, and Mars is, in many ways our home as well.
Marissa Lo: Where can people listen to your music?
Divya Persaud: Yeah, I have a SoundCloud. I can give you the link and also on my website, which is just my full name, dot com.
Marissa Lo: Well, thank you so much for sharing everything about your research and all of your interests with us.
Divya Persaud: It’s been great speaking with you.
