The Future of Space Telescopes

ROMA AGRAWAL

There seems to be a universal fascination with the possibilities that come from gazing at other planets. The idea that there's new worlds to be discovered. Ecosystems, maybe even life, that exists outside our own. Today, now more than ever, we have the technology to explore this unknown. I'm Roma Agrawal and you're listening to Create the Future from the Queen Elizabeth Prize for Engineering. In this episode, we dig deep into the engineering possibilities behind space telescopes. Joining me are Professor Garth Illingworth, Distinguished Professor of Astronomy and Astrophysics at the University of California, Santa Cruz, and Professor Jonathan Lunine, Professor in Physical Science at Cornell University. Together, we explore the latest research developments in the field, from the Hubble to the James Webb telescopes at NASA.

PROFESSOR GARTH ILLINGWORTH

Take this huge telescope that we build on the ground and test on the ground, and then you fold it up to fit into the top of the rocket.

ROMA AGRAWAL

How they can reveal not just other worlds, but insights into planet Earth as well.

PROFESSOR JONATHAN LUNINE

The things we learn, the basic knowledge that comes out of observations of nature really do change our lives.

PROFESSOR GARTH ILLINGWORTH

What we're doing here is we are exploring our origins and helping us understand where we came from.

ROMA AGRAWAL

And the ethical questions raised from these explorations.

PROFESSOR JONATHAN LUNINE

You know, as we go out in the solar system, as we do things on the moon, as we land on Mars and collect things. Do we have a right to do that?

ROMA AGRAWAL

So join us as we gaze towards new horizons and explore how these telescopes offer a lens to a radical new future of space discovery. Right, so it's really exciting to have two people here today that look into telescopes that show us our universe. So, Jonathan, I'd love to hear a little bit about what sorts of things you're looking at when you're looking, metaphorically, through your telescope. And do you look through a telescope or do you get stuff on a computer?Let's paint a picture for what this is like.

PROFESSOR JONATHAN LUNINE

Sure. Well, I get the data on a computer. I don't look through a space telescope. And also, my data, although they're extremely interesting, are not in the form of pictures, they're in the form of what are called spectra. Which is…if you want to think of it as the brightness as a function of colour, or wavelength of light that comes from an object in the universe, in my case, a planet around another star, or some of the more distant very cold objects in our own solar system that are called Kuiper Belt Objects. So, when I get these data, and they're converted into something I would look at, it's a bunch of lines and squiggles on a graph. Sounds exciting, right?

ROMA AGRAWAL

Not quite what you expect.

PROFESSOR JONATHAN LUNINE

Right.

ROMA AGRAWAL

So the lines and squiggles are telling you what sort of light is coming off your object? What's the kind of information that you're gathering from that?

PROFESSOR JONATHAN LUNINE

Yes, it's telling me what the distribution of light as a function of colour. Colour is the sort of subjective way we think about the wavelengths of light. Light is waves and human eye can only see a very narrow part of what we call the electromagnetic spectrum of light. So I, the data that I look at from James Webb Space Telescope is just beyond the range of human sight in the infrared, and the information that comes back is the composition of the surfaces of some of these objects or their atmospheres. What are they made of? What kinds of molecules are present, either in the atmosphere or on the surface? And so this is a way of telling us a lot about the nature of these objects.

ROMA AGRAWAL

And if our listeners haven't ever seen what the James Webb Telescope looks like, could you maybe describe that for us, please?

PROFESSOR JONATHAN LUNINE

James Webb Space Telescope looks a lot to me like a giant insect. It's not like the usual telescope that you think of with a tube and an eyepiece at one end and then the mirror at the other end and a cylindrical tube in between. Actually, the mirror is exposed to space and it's made up of multiple smaller mirrors that roughly appear in a sort of hexagonal shape. Very large, six and a half meters across and then that giant mirror has a sort of a neck. It's bolted down onto a structure that has these very, very large shields or sun shields that are about the size of a, sort of a singles tennis court. Underneath that is a spacecraft with solar panels and thrusters and a communications antenna and mounted to the back of the big antenna, which I think of a sort of the giant head of the insect, are the instruments. That's where all the light goes to give us the information we want. So, that's how I visualize it. Garth may see it in a different way.

ROMA AGRAWAL

The big bug. Yes. Garth, your turn to tell us what you're looking at.

PROFESSOR GARTH ILLINGWORTH

Certainly. So, let me just say a few words about the telescope too. So, Jonathan and I have both worked on this for decades.In fact, I started working on this back in the late 1980s. And we had a very simple concept then, which was much more tube-like. But then as we realized that we wanted to fly a very large telescope, and the rockets were not big enough, what we had to do was have something that would fold up. And so it was like a transformer.

You take this huge telescope that we build on the ground and test on the ground, and then you fold it up to fit into the top of the rocket. And as we went out, we're shot out from the Earth on the Ariane Rocket, the telescope was let go and then was propelled out past the moon out to its place in the sky, one and a half million kilometers from Earth. And there, by the time it got there, it was fully unfolded. And as Jonathan described it, it's a very open and very different telescope. And the sunshield is really the defining part of this telescope. There's five layers of very thin aluminized plastic material that prevent the sun from heating the telescope. Because this telescope has to be cold to be able to work where we want to work, that… much longer wavelengths than our eyes can see, it's past the red into the infrared. And at that point, we need to have a telescope that is really cold. And fortunately, the universe is really cold. It's a wonderful refrigerator. And so if we can stop sunlight falling on our telescope, it will cool down and it has. So, it's cooled down hundreds of degrees and is only now about 40 to 50 degrees above absolute zero. So that's the telescope, which is sitting there on one side, as Jonathan explained. And then there's the sunshield, the five layers and then there's the hot side where all the communications and power and propulsion system are. But it is a very open telescope, as Jonathan said. There is no tube on this one. It's this array of 18 hexagonal mirrors, beryllium, very unusual material, but perfect for a cold telescope. Light hits that, and then goes down into the instruments, as he said. And that is all open to the universe to keep that really cold. So it's an amazing technical feat to do this telescope.

ROMA AGRAWAL

Are you looking at squiggles in a similar way to Jonathan?

PROFESSOR GARTH ILLINGWORTH

No, so let me say a little bit about that. So, for a couple of decades, I've been using Hubble to look at the very earliest galaxies in the universe.

So, very different. So, Jonathan and I are working, as it were, at different ends of the universe. I'm working at the beginnings of time and Jonathan is trying to understand a lot about the nearest objects to us and their relationship to Earth and so on, and other planets and so on. So, I'm looking at galaxies like our Milky Way when they're being born. And this interestingly is what we really set out to do with this telescope. When Hubble first flew and got its wonderful images, full of these very distant galaxies, we were so entranced by the information that was in there, but we couldn't really get to it with Hubble. And so we immediately picked up that as the primary goal, at that time, for what James Webb, or what was called the Next Generation Space Telescope in those days, would actually do. So, the goal was to take images of these very earliest objects with much more detail and insight than we could ever do with Hubble.

ROMA AGRAWAL

It sounds like there are some really massive engineering challenges in creating these sorts of telescopes. So, you know, you've mentioned temperature, for example, we're working at temperatures that you don't get on earth. So, you're thinking about materials. I'm guessing there are issues with stuff flying around in space. Like, maybe Jonathan, could you talk us through some of those sorts of engineering challenges that you need to think about when you're designing and launching telescopes such as these?

PROFESSOR JONATHAN LUNINE

Well, one thing I always like to say in response to a question like that is that I'm a scientist and not an engineer. And one of the most impressive things that I witnessed during the development of this telescope, I don't go quite as far back as Garth does, but I go back to, I guess, 20 years; this enormous engineering challenge of being able to see the very faintest objects in the universe, much fainter, more distant than what Hubble could do. I mean, that was an extraordinary engineering challenge. It's not just being able to put the telescope in a cold part of space away from the earth, it's also making sure that the telescope itself doesn't radiate heat into the mirror where,you know, all that information is coming in. And yet at the same time, you have to be able to collect sunlight, you have to be able to communicate with the Earth so part of the telescope has to face the sun.

And so the difference in temperature between the hot side and the cold side, as Garth said, and making sure that that sunshield would unfold. Those five layers would unfold to precisely the shape that you need because any sort of irregularities would lead to some light from the hot side being scattered onto the cold side and that would really degrade the sensitivity. These were extraordinary engineering challenges that were solved by engineers over many, many years. And then being able to move this enormous structure with these relatively floppy sunshields. I mean, this isn't like a solid spacecraft it’s more like a sailing ship, in a way, to move it and to hold it precisely and to have it track what are called the guide stars to be able to stay fixed on the right objects. That also was a tremendous engineering challenge.

PROFESSOR GARTH ILLINGWORTH

One of the things that always struck me as amazingly difficult, Jonathan mentioned the sunshield and I did too as well,these five layers of material that have to be very precisely positioned. And this is floppy material, like paper thin material and the size of a tennis court. And I know when I was out at Northrop Grumman, who was the prime contractor at one stage many, many years ago, and I walked around their engineering model - their full scale engineering model - and I looked and I thought, and I sort of said to myself, this is never going to work. There were cables and motors all over the place. And of course it was hard, there were a lot of problems. But NASA, Northrop Grumman, the contractors did an amazing job of bringing this together and making it such that we could fold this up and roll everything up. Launch it on this spacecraft. Spread out some arms. Pull out the material. Separate it. And it all worked.That, I think, is an incredible engineering challenge and feat on the part of everybody who was involved.

ROMA AGRAWAL

Jonathan, I want to hear from you. How can this technology impact our lives on Earth?

PROFESSOR JONATHAN LUNINE

Well, first of all, in terms of the science, one of the things that I think we've learned over… depends on how far back you go, to the beginning of the Enlightenment, that the things we learn, the basic knowledge that comes out of observations of nature, really do change our lives. They may not change our lives in the next year, or in the next ten years but they are part of this growing base of understanding of nature itself that does have an impact in the decades and centuries to come. So, that increase in basic knowledge is very, very important. And near term, a lot of the technologies that were involved in this mission do get utilized in other kinds of systems. I'll go back to Hubble Space Telescope. A lot of the technology associated with Hubble Space Telescope had actually been developed at some level for observing the Earth, not so much for the environment but more for national security, for example, and that got applied to astronomy. In terms of the things we learn about, I'll take my own area, which is planets.

You know, one of the big questions is, why is the earth habitable? How has it supported life for billions of years? How unusual or typical is our own planet? And what James Webb Space Telescope has the capability to do, and is doing, is observing planets that are really not that much bigger than the Earth and asks what their nature is. Do they have atmospheres? And if they have atmospheres, what is the composition of those atmospheres? What is the typical nature of a planet the size of the Earth around other stars? And so, we're starting with the data from Webb to build up an understanding of that. So, getting that perspective of how unusual our own home planet might be in a much larger cohort of planets elsewhere in the galaxy is a really important part of understanding our place in the universe.

PROFESSOR GARTH ILLINGWORTH

So, Roma, I probably should give you a little update, too, because this question that you asked is very important. I get asked it all the time in talks. And that's the one about, you know, what benefit is there to the human race to do these projects? And, as Jonathan noted and I would agree, I think that scientific results are very important for our understanding of the universe. And I answer it this way. I think that we are intrinsically interested, as people, in our origins. And that's our origins, you know, as the human race, as the Earth, as the Sun, as the Milky Way, and we can take it out to the largest scale. And so, I tell people that what we're doing here is we are exploring our origins and helping us understand where we came from. And while these facilities are very expensive, this cultural value of doing these experiments, of doing these new telescopes, of learning about our universe, is a bargain for the human race. It's not much money compared to…very little compared to what we spend on defense industries and other things. And it's, I think, part of our development as people, our intellectual…our understanding of the universe. And so, I don't get into much into saying there's a lot of flow down technologically, which of course there is, but I really do think that the bigger value of this is that it's part of our sort of innate desire to explore. And we may not be going out and exploring by setting foot on somewhere, but we're exploring and expanding our understanding, our worldview and our minds from what the universe is like. So that's what I'd like to emphasize to people. That by supporting this, by seeing the results from this, you are getting insights into your origins, our origins.

ROMA AGRAWAL

What's the most unexpected discovery that you've come across in your career, Jonathan?

PROFESSOR JONATHAN LUNINE

Oh goodness. So, I guess in general…So I've…most of my work has been with planetary missions, spacecraft that actually go out to the planets and moons of our own solar system. And there, I have to say that, for me, the most surprising discovery was that a small moon of Saturn, with a not very attractive name (Enceladus) has a plume of ice and gas that is pouring out of fractures in the South Polar region coming from yet another liquid water ocean. This is a small moon, did not expect there should be an ocean. By the way, that plume is being observed by James Webb Space Telescope. And that has provided very important information because Webb looks at a larger scale and to a deeper sensitivity than the remote sensing instruments on the mission that actually discovered the plume Cassini was able to do. But Cassini had instruments that could actually sample this plume, tasted if you will, instruments called mass spectrometers. And those detected organic molecules, salts, as well as the water, at least one mineral, silicon dioxide. And so, this tiny moon of Saturn, barely 300 miles across, seems to have an ocean with all the ingredients that would support life. And we hope to go back there someday with instruments that could detect life, but in the meantime, an outstanding question is: how persistent is that plume? And James Webb Space Telescope is giving us precisely that information. It seems that the plume of material is as substantial as it was when Cassini was there, and that's very important. So, there's this wonderful link between what I would say, personally, is one of the most surprising discoveries for me, the discovery in 2005 of this plume by Cassini and what James Webb is doing today.

PROFESSOR GARTH ILLINGWORTH

I have to say that a highlight for me, scientifically, was when we discovered with Hubble the most distant galaxy ever. This was back in about 2014/2015. It took us back through about 95/96 percent of all time, close to the beginnings of the universe. It was unusually bright. Was unexpectedly bright. And so that was a real conundrum, trying to understand, where did this galaxy come from? And this was the only one that was found like that with Hubble. And for many years, it basically was the record holder for Hubble. So James Webb comes along, and within the first week, we found an even further galaxy and then within weeks, we had a handful of these galaxies, all of which were extremely bright. And this led to a lot of head scratching because this was unexpected. And so we have these bright galaxies that we're seeing and we're trying to understand how they could be so bright so early on in the universe. We have thought about how they're really very massive. What's going on here? So it led to a lot of speculation and some wild claims about “our cosmology is all wrong,” which I think is not true. We don't understand enough about these galaxies to be able to draw much broader conclusions, but what we are starting to see after a year and a half of observations is many of these galaxies have big black holes in them, and they are contributing to the light. We may be looking at different populations of stars. We don't quite understand that yet. We need more of what Jonathan was talking about in the way of spectra spreading out the light to be able to interpret these. So we're still at a very interesting phase here and asking ourselves, are there things happening amongst the early galaxies that we really do not understand? Do not fit with our models, with our view of how galaxies should grow in the early universe? So that's a wonderful open question that I think we're still exploring. But I think that the finding these bright black holes has actually been another major step. So, not only bright galaxies, but big black holes at early times. And that raises another question. How do you form a black hole that massive so early? So, every one of these discoveries adds to our, sort of, list of questions and challenges. And so I think there's a lot of people who are working with trying to get data on James Webb and to understand what this early phase of the galaxies was like in the universe. So, Webb is really entrancing us in that area as well as many of the others.

ROMA AGRAWAL

Jonathan, can you talk us through the idea of space ethics? You know, as we're going further and further out and exploring more, and we've got politics on earth that may be limiting us potentially, what is space ethics? What are the things we should be thinking about? And do we have any solutions to these conundrums?

PROFESSOR JONATHAN LUNINE

Well, that’s a very different question than the science on James Webb Space Telescope. Webb is collecting photons of light which, as far as we can tell, is an ethics neutral activity. You know, there are things we do as we explore where ethical issues do come up. There was a mission back in 2005 called Deep Impact. And the idea of that mission was to be able to determine the composition of the nucleus of a comet. But not the very outside, which is encrusted with dust that has remained as ice evaporates away during every passage of a comet by the Sun and that makes it hard to be able to detect some of the ices that tell us about its origin.

So, the idea was to fling a cannonball at this comet. Blast a piece of the crust off. And take spectra of that fresh area as the spacecraft passed by. So, that was all very successful. And I happened to be teaching at something called the Vatican Observatory Summer School that summer. And so, the morning after the successful excavation of this piece of the nucleus, I showed a slide of this impact of this metal ball, started talking about the science and one of the students raised her hand and she said quite assertively, “what right do we have to alter or destroy the surface of this comet?”

And it really was a complete surprise to me because I didn't think at all about that. It was an interesting question, you know, as we go out in the Solar System, as we do things on the Moon, as we land on Mars and collect things. As perhaps the only self aware intelligent species within our Solar System - that certainly must be the case, probably is the case. Do we have a right to do that? So I think that's one area. The other, which I think is perhaps even more problematic, is the question of both bringing samples back from places where life might exist and also potentially contaminating those places where life may exist. So the problem of making sure that we don't contaminate places on Mars where there might be life, or the oceans of Europa and Enceladus, that's called forward planetary protection. The question of making sure we don't bring back things that might potentially harm us on Earth is backward planetary protection. And both of those are in play for Mars, where there are samples being collected now, hopefully for return to the Earth in the next decade by the Perseverance Rover. And one of the issues in the design of that mission is making sure that any dust that might remain on the outside of the sample containers, the sample containers themselves are sealed but Martian dust could end up on the outside, is sterilizing that on the way back to the Earth to make sure that there isn't anything that potentially could harm us. And I think in terms of pure exploration, deep Space exploration. Those are really the ethical issues. I mean, there's a whole raft of others that don't have to do with science, you know, destroying satellites in low Earth orbit, which creates incredible debris fields, the possibility of nuclear weapons in orbit, all those sorts of things really out of the purview of this discussion. But these deep Space issues are still issues that we have to worry about for our Solar System.

PROFESSOR GARTH ILLINGWORTH

Let me just also add just a quick comment. So, Jonathan has noted some very serious issues with regard to activities in space. Fortunately, for astronomers like us where we're launching a telescope, it really is just a information gathering machine. It sits there, in a sense, passively gathering information very far from Earth. And so those sort of issues, thank goodness, do not arise for our telescopes like Webb and the others that fly out there.

ROMA AGRAWAL

Garth, what else do you see in the future these sorts of Space missions? What's the future of astronomy and telescope and data gathering?

PROFESSOR GARTH ILLINGWORTH

This is interesting. So, every 10 years, we establish a broadly based committee of astronomers to think through what we would like to see done in Space and on the ground to further the field. We call these the decadal surveys. And so, you know, these are reports that come out every 10 years and they're offered up as advice to the agencies that fund science to Congress and to the administration. We did that for James Webb. It was called Next Generation Space Telescope in 2000. It was recommended at that point that that be built. In 2010 there was another telescope that was recommended called WFIRST, which is now called the Roman Space Telescope, and that is being built to be operational towards the end of this decade. So, we had another one just a few years ago in 2020/2021 that recommended that we move forward on what is now called the Habitable Worlds Observatory. This is a telescope which would be large, would be again far from Earth and so on, but its main goal would be to try and find and particularly characterize planets that may be like Earth. And to do so with the goal of assessing whether there's life on these planets. The life aspect has become a great interest to the communities and this is a really challenging project. It's sort of the size of Webb, but it may well cost even more than James Webb to do this. And so we have asked NASA to look at this project as a future project in Space. Webb is finished, but the Roman Space Telescope is being built so that takes up the budget for big projects for some time. Once that goes, then there's an opportunity to start using funds for another big project and the Habitable Worlds Observatory is the one that NASA would like to do. So, that's the other aspect of our big survey program for 2020, which we're hoping to achieve, is to do something huge on the ground and something huge in space. But it takes a long time to do these. It's going to be many years.

PROFESSOR JONATHAN LUNINE

It's great to think about the future, but James Webb Space Telescope is the future because we certainly hope there will be many, many more years of discoveries. And the things that are being discovered now with Webb are the payoff of this investment of what was 20 years of extraordinary technological and financial effort prior to which there were a couple of decades of studies. And so this really is - Webb is a generational accomplishment.

ROMA AGRAWAL

Garth, what are you looking forward to maybe discovering before you retire, if that's on the cards?

PROFESSOR GARTH ILLINGWORTH

So, I actually have retired but I have continued working. And I've really continued working because the Telescope has just truly fascinated me. And also, it's been an opportunity to now get into some science that I've wanted to do for so long. And it's beyond what we could do with Hubble. So I am just intrigued by what is going on in these early galaxies. And I expect it will take some many years of work to sort this out but Webb has the ability to do that. So, I like Jonathan's comment about, you know, being the future. It's the future. It's here now, but it is the future of so much of the science that we, many of us want to do - all of us want to do - in different ways. And for me, it's understanding the earliest galaxies and how they started, how they grew and what was going on 13.5 billion years ago when the very earliest galaxies started to form.

ROMA AGRAWAL

You've been listening to Create the Future, a podcast from the Queen Elizabeth Prize for Engineering and Peanut and Crumb. This episode was hosted by me, Roma Agrawal, and featured Professor Garth Illingworth and Professor Jonathan Lunine. If you enjoyed this and want to learn even more about the world of space exploration, be sure to check out our episode on Mars missions with mechanical engineer Abby Hutte and physicist and former chief NASA scientist Jim Green.

JIM GREEN

Well, in the future I think we will answer the question “are we alone?” And we'll learn an enormous amount from that discovery.

ROMA AGRAWAL

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