Transcript: Space4U podcast, Steven Hawley

Written by: Space Foundation Editorial Team

Hello, I’m Rich Cooper of Space Foundation. And this is Space4U. A podcast dedicated to sharing the stories, insights, and reflections of the diverse men and women who are part of today’s space adventure. Human history is filled with stories about the ideas and insights people have had when they looked into the night skies at the stars above them.


That wonder and curiosity led to the creation of the first space science: astronomy. And today’s Space4U is joined by someone who has really had his hands on some of the most revolutionary astronomy tools that have changed our understanding of our universe. Dr. Steven Hawley is professor emeritus of physics and astronomy with the university of Kansas and a five time space shuttle flying astronaut who had major roles in the deployment and later upkeep of the Hubble space telescope.


As well as the launch of the Chaundra x-ray observatory, we had a chance to speak with him about those experiences his start with astronomy, as well as his thoughts on the launch and mission of the James Webb space telescope. Here’s what he told us. It’s a pleasure to speak with you. We have Dr. Steven Hawley here with us.


I literally want to start at the beginning. Tell me about your first telescope. I actually remember it very well. It was a Christmas present. I got from my parents when I was in grade school. I don’t remember specifically which grade it was a little four and a half inch reflecting telescope, Newtonian reflector.


It had a metal mirror and a clamp. Uh, so it didn’t even have a, a stand or a tripod. Clamp it to the back of a chair. So it was pretty primitive, but it was the first telescope I had and I learned of course had no features that you find today on telescopes that you can buy for your own personal use, like go-to features where it’s all computerized.


You don’t actually have to know your way around the sky. So, uh, probably learning to use that telescope also taught me a lot about, uh, how to navigate around, uh, the constellations and the different stars. Was there a particular star or constellation that really captured your interest or imagination that you wanted to learn more about when you started with astronomy?


Well, probably, Orion was the constellation that, that I knew best because it was easy for me to find, but what really captivated my interest frankly at about that time was, um, reading books about astronomy and astronomers and discovering that astronomy was a little unique in the sense that as a chemist or a biologist or a physicist, you could conduct an experiment.


You could set up some conditions, expect an outcome. See what the outcome is it either validates or it doesn’t validate your hypothesis. You could change your experiment and see how that affects the outcomes. What I learned as a kid was that astronomers don’t get to do experiments. All they get to do is look at the sky and see what they can see.


And if they’re really clever about what they’re looking at, they may be able to make some progress in understanding the universe. And I just thought that was tremendously fascinating, how people could good figure things out just by looking. So when you talk about not doing experiments and learning by looking, we have this incredible instrument called the Hubble space telescope, which was launched, aboard a shuttle mission that you were part of in 1990.


I remember it well, because this was the first of space-based telescopes that we’ve ever had. Can you share with us a bit of what your role was in the launch of the Hubble space telescope and what your role was in its deployment. Sure. I was, uh, there were five of us on the crew and the way the tasks were divided, I was to be the robot arm operator and Kathy Sullivan and Bruce McCandless were to be the EVA specialists.


The way Hubble was launched, it was actually designed of course, to take full advantage of the payload bay of the shuttle. So it basically filled the payload bay when we launched. And once we got on orbit, assuming we got to a high enough orbit to permit release of, of the Hubble. Uh, my job was to operate the arm, to grasp the telescope lift it out of the payload bay and release it.


Yeah, well that sounds simple enough on the surface. It actually was quite complicated and there are a lot of what-ifs that we had to think about. In terms of just the deployment itself. There are places where you want the sun to shine. There are places where you never want the sun to shine with respect to surfaces on HST.


Where can you put the telescope so you get good communication with the ground. So the crew can see critical events like the deployment of the solar arrays also it’s massive enough. And it would get far enough from the center of gravity of discovery. That the autopilot was unstable. And so there were unique ways that we had to develop, uh, with the flight controllers, how to control the orbiter during this process.


And there were a number of things that could fail. That would require Bruce and Kathy to go do a spacewalk to fix the most critical was the fact that by necessity, the solar arrays were rolled up and stowed along the side of the telescope while it was in the bay, it was getting power from the shuttle, but to deploy Hubble, we had to unplug it.


So now it’s on battery. Which is okay. Assuming the solar arrays come out. So an important what if was, what if they don’t. And that was one of the tasks that Bruce and Kathy had had trained for, would be to, uh, in that event to do a spacewalk, to manually roll out the solar arrays and get power to the telescope before the batteries would run out.


And we’re talking about an instrument, that’s the size of a school bus. Right. And the most massive thing that the shuttle had ever flown. At least Up to that time. And so essentially your job is I am to lift the school bus out of the back of a spacecraft going 17,500 miles an hour and make sure I don’t point it to the sun and my crew mates go out, have to put these pieces in and make sure nothing bad happens.


Yeah. It was daunting actually, a lot of places where, where things could go wrong in a hurry. So when your crew mates go out, they connect the solar arrays. It’s able to generate its own power. You release it. And unfortunately we find out a couple months later, Hubble isn’t working as it was aspired and intended.


Can you explain to me a little bit about Hubble, how it’s supposed to work and why didn’t it operate as intended at first? Sure the telescope design is a form of a Cassegrain telescope. Cassegrain telescope is as opposed to my four and a half inch Newtonian reflector, where the eyepiece is at the open end of the tube.


Cassegrain has a primary mirror with a hole in it. And so the light comes in, they open into the tube, hits the mirror. The primary mirror is reflecting. To a secondary mirror and that secondary mirror reflects light back through the hole in the main mirror. That’s a very common design for big telescopes on the ground.


And it has an advantage that you can put detectors, which on the ground, or can be fairly massive behind the primary mirror, which makes the center of gravity manageable. And it makes for a more efficient engineering design. And that was the design of HST. There is, it’s actually a little more sophisticated than that.


Cause the mirrors on HST, uh, are, uh, hyperbolas, often mirrors are parabolas, rarely are they spheres like my four and a half inch telescope. The sphere is easy to make and it’s easy to test, but it has the feature that it won’t focus. All of the light at a single point. If your telescope is small enough, that doesn’t really matter.


A parabola on the other hand will focus the light at a single point. And so for modest telescopes, generally the mirrors were parabolic. However, the image quality around the field of view for a parabola isn’t as good as you might want. And for HST, the mirrors were going to be hyperbolas which do have very good image quality over a wide field of view.


The problem with hyperbolic mirrors is that they’re difficult to make and they’re difficult to test. So once we got HST on orbit and it began to operate and we were getting our first images, what we saw was that the images were out of focus. And initially I remember there was discussion of, well, you know, we’ll just, we can tweak the focus a little bit and, and, and maybe fix this problem.


Well, it turned out that that was not the case, that it could not be tweaked, that it was just going to be out of focus. And there was an investigation. And what was discovered was that the mirror had this condition called spherical aberration. Which says that in principle that the images are not going to be as precise as required because the light wouldn’t come to a focus at the same place.


And so obviously that was a gut punch for NASA because this was, you know, an extremely important mission and with all kinds of promise for rewriting the textbooks on astronomy. And suddenly now we’ve got a defective mirror on orbit. The reason it ended up that way was because these mirrors are hard to test and the contractor had built a testing device called a null corrector.


And they actually had a couple of different, null correctors, but one of them was assembled incorrectly. And so what it told them was. The mirror was in fact ground to the right specification when in fact it wasn’t, and it was it’s commonly accepted that the HST mirror was ground more precisely than any mirror ever made.


The problem was it was just ground to the wrong shape. And so, you know, that was a real issue. What are we going to do? If we can do anything to save the day? Now, obviously when you get a wrong pair of lenses for your glasses, it’s easy to go ahead and replace those lenses. Replacing the lens on a orbiting telescope is a little bit different.


How do you correct for lenses that are wrong on an instrument like this. Right. So one, I guess, fortunate aspect to this was that because of the investigation that was done, we knew the mirror wasn’t right. But we also knew, uh, what the shape of the mirror was. And so in principle you could make just as your eyes, your own eyes over time, when you get to be my age, they don’t work so well.


So I wear glasses. Well, if you can measure the prescription that you need, you can. Create, essentially glasses that would correct the image that is distorted by the main mirror. And that was what was done. The team figured out how to build an instrument. It was called CoStar, which stood for corrective optics space telescope axial replacement, and what it was, was a series of mirrors and lenses and armatures that.


You could install in the telescope and then deploy these mirrors and lenses with the armatures, into the light path, to the different instruments. And if it was all done properly, then the mirrors and the lenses in CoStar would compensate for the distortion caused by the main mirror. And I remember when I first heard that concept, I thought this has no chance.


It’s too complicated. Yeah, we know how to make the moves and lenses can, you know, can we get them in the right place, in zero gravity? And you know, so I was kind of skeptical, frankly, but that seemed to be the best shot. We had one other instrument that was going to be replaced on the first servicing mission, which was the Wide field camera.


Wide field planetary camera one was replaced with Wide field planetary camera two, and that instrument could be built with its own set of correcting optics. So that wasn’t going to be an issue, assuming that we had the prescription correct. So that was the plan. If it all worked, we might be able to restore the required performance and the original specifications.


So we, the mission goes up to Hubble, makes the correction fine tuning and adjustments are made. And it works since literally the early nineties, when the Hubble was released and started its operations, its images have made news around the world, but while it’s made news, Hubble is also changed history and science in so many ways.


I’m curious from someone who’s been an astronomer and someone who has been personally involved with its deployment. What do you think Hubble tells us about our universe? Well, it’s interesting to think back to before 1990 pone of the, the key questions in astronomy was what is the Hubble constant Hubble constant measures, the rate at which the universe is expanding and it also directly.


Tells you an estimate of the age of the universe, an important problem back then was the fact that we didn’t actually know the Hubble constant, all that well, we didn’t know that to an accuracy of a factor of two. And so the universe was, you know, maybe 10 billion. Years old on one end of the scale or 20 billion years old on the other end.


And 10 billion was kind of a problem because we were sure that there are objects in the universe that were older than 10 billion years. And so in fact, the measurement of the Hubble constant their end also, therefore the age of the universe was referred to as the Hubble key project and Hubble could do it because it had.


Better sensitivity and better resolution than any other telescope we had, except that we couldn’t do the problem until the repair was in, uh, on the first servicing mission because the telescope did not have the required sensitivity and resolution simultaneously, but when the CoStar was installed and the image resolution was, was restored.


People were able to do that study. And suddenly we learned that the homo constant was around 72 kilometers per second, per mega parsec that made the age of the universe about 14 billion years. And that was dramatically important. And that was one of the first major discoveries that HST has made. Of course, in the decade, since there’ve been some that you might argue or even more.


Important, uh, one that comes to mind is basically trying to refine our knowledge of the Hubble constant within the last 10 years or so maybe a little bit more 10 or 15 years. We discovered this thing. We now call dark energy and dark energy. We have a name for it, but we don’t know what it is, but the effect of dark energy.


Is to cause the expansion of the universe to actually be accelerating. And that’s just sort of bizarre and we don’t really understand what’s going on, but Hubble was key to being able to at least discover that this thing we call dark energy exists. It was also very useful at discovering another component of the universe, which is dark matter.


Dark matter is the name we give for. Some kind of matter that interacts only by gravitation. It doesn’t interact with light. It doesn’t emit light, doesn’t absorb light and together dark matter and dark energy make up about 95% of what makes up the universe. And so, you know, I guess if there was maybe one takeaway from what Hubble has done, it would be that.


Hubble has told us that everything that we understood prior to Hubble makes up no more than 5% of what makes up the universe. 95% of what makes up the universe of stuff that we have a name for, but we don’t know what it is. You talk about the science. You talk about the knowledge you talk about all of those particular breakthroughs, but one of the things that has truly captured the public’s imagination or the various Hubble images that have come out.


Those Hubble images though, are colored when they’re released to the public. Can you give us a little bit of an understanding of why those images are colored and how are they colored that particular way? Because again, I, it’s not unusual to see screensavers or posters or prints of what Hubble has discovered, but again, these are false colors that we’re seeing.


Right. They are, we generally obtain the imagery through filters, which allow light of certain wavelengths to pass. And of course, then we measure the intensity of the light through various filters and that allows us to create the false color. And in many cases, the false color is intended to show you what it would look like.


If you could really look at it with your naked eye. In other cases, that’s not true. In other cases, the false color is there to emphasize some part of the science and that that’s the part that’s been of interest to me in my astronomy career, because I study nebulae. That could galaxies where a lot of the light comes out in very, very narrow wavelength bands.


And those, those emissions are associated usually with a specific type of atom. And so you may. See a picture of a Nebula where some of it is, is shown in red. And that’s because that’s where hydrogen is admitting. And other parts of it are in green. And that’s where doubly ionized oxygen is emitting.


And maybe some of it’s kind of a violet color. And that may be where, where triply ionized, neon is, is emitting. And, and that way you can see where. The different elements exist and that’s, uh, helpful. Particularly if you’re looking at remnants of dying stars to see, uh, where the elements created by the star during its lifetime have ended up either because.


The star like the sun, you know, went through this process where it gave off its atmosphere as it aged, but in a more sort of slow and controlled manner, as opposed to some stars that are more massive, that explode and the elements are distributed in a gigantic explosion. So it depends a bit on whether you want to produce a picture that, that you could say, this is what it would look like.


If you could really. See it up close with your eyes or whether you want to produce an image that might be more illustrative, you know, at, at highlighting some of the underlying science. Hubble is part of a series of space-based telescopes. Do they work better in space than earth? Yeah. Hubble is part of the program goes back to somewhere in the seventies, I think called the great observatories program.


And the idea was to have four large capable. Space-based telescopes that would span the entire spectrum from high energy gamma rays out to low energy infrared. And it’s desirable to go to space for a couple of reasons. One important reason is the earth’s atmosphere. Isn’t transparent to all wavelengths that are interesting to astrophysicists.


Uh, for example, a lot of where the Chandra x-ray observatory. You know, observes, you’d never be able to do that from the ground. And that’s also true of the Compton Gamma Ray observatory, and a lot of what the Spitzer telescope can do. Hubble actually does observe beyond the region where you can see from the ground, but a lot of what it does overlaps with what you do.


With ground-based telescopes. So the other reason to put a telescope in space is to get above the atmosphere because the atmosphere has current and turbulence and it smears the images. And this is why we say stars. Twinkle is because while some stars do intrinsically twinkle, but the, primarily as the Starlight comes through the atmosphere, it gets moved around a bit by the air currents.


And so. That Puts a limit on how precise, an image you can get, but the atmosphere you don’t have that problem, you can get as good an image as your instrument will allow. And so it’s a combination of things. When I was in grad school, we really felt like. We had done the best we could do in building ground-based telescopes, the 200 inch at Mount Palomar.


Wasn’t physically the biggest in the world. The Russians actually had a six meter telescope, but it didn’t work very well. So it was the biggest, useful telescope. And frankly, we didn’t think you could build a bigger one. The mirrors just get so big that. They will deform under their own weight. It just, and it becomes a monstrosity to try to design a, a dome and a mounting.


So the other reason to go to space is because we’ve done all we can do from the ground. Well, that part turned out not to be right over the decades since. Yes, it was too difficult to make a monolithic mirror that was bigger than the Palomar 200 inch, but clever people figure it out. Well, what if we don’t make it as one big piece of glass?


What if we make it up of a bunch of segments, each of which is, you know, fairly lightweight. And if we could do that and build a mosaic and get all of the little. Mirror elements to work together. You could build a big mirror and it wouldn’t be too massive to function. The thing that made that possible was computing to have microprocessors that could control the different mirror segments and get them to work as one big mirror.


And so now we have 10 meter telescopes on the ground, and fortunately, because. Hubble does observe in wavelengths that ground-based telescopes can observe for the last 30 years, we’ve probably made more progress than we could have anticipated by having Hubble in orbit and these massive 10 meter telescopes on the ground to work collaboratively.


And so that was kind of an unexpected benefit of how having the telescope in space and these big telescopes on the ground work together. So Hubble has been in operation for more than 30 years and continues to put out incredible imagery, but even more powerful science. Is there a particular image or discovery that has resonated with you?


There are two. Actually the one that I always said was my favorite Hubble image was the original Hubble deep field. Bob Williams was the director of the space telescope science Institute back then. And he devoted some of his director’s discretionary time to addressing the question of what would happen if we took a really long photograph, long exposure of a region of the sky, where there isn’t anything.


Would we see anything and they picked a region, uh, in the Northern hemisphere, near the handle of the big dipper, which is a way for them playing the Milky way, which would obscure your ability to see beyond the galaxy. And it was also away from any known clusters of galaxies. So far as anybody knew it could be an empty field.


And this was after of course, the, first servicing mission. And they took a 10 day exposure and I was, I don’t know how other people felt. I was shocked when I saw what was seen. The image showed a sky full of objects. Maybe in the deep field, something like 12 or 1300 objects and almost every one of them was a galaxy.


And so this region of the sky that we thought could be empty was actually full of galaxies. And since that time there’ve been other deep fields taken, there’s been the ultra deep field. And so these types of very deep images have been really crucial in advancing the science. But for me, it was just kind of a shock to see this long exposure of an empty part of the sky reveal that the universe, which is full of galaxies,


What was it like to return to Hubble after releasing it, you were part of a servicing mission. You could call it, uh, you know, coming back home, uh, in some respect, what was it like to go back to Hubble and work on it? Its enhancements and give it even more life and more capacity. Well, I, I considered it a great privilege.


Hubble missions back in the day were highly desirable. All, all of us wanted to fly Hubble missions and to be able to fly two of them was quite special. One thing I remember that was different when I was sitting on the launch pad for that mission from all of my previous missions, this one was different because we were going to go somewhere.


Specific place in space and do a job, do work. And so somehow that felt a little different because many of my missions, it didn’t matter exactly which orbit we ended up in. If we’re going to deploy a satellite or do something else to do some experiments on board, but this, this was different because we were going to go to a specific place where there was an object.


And we were going to work on that object. So that seemed like a next, next level step in the maturation of the space shuttle program. One of the things I remember about it was that the solar arrays that were on HST at the time were very fragile. The original solar arrays that we launched back in 1990 were replaced on the first servicing mission in 1993.


In part, because the original solar arrays imparted a vibration to the telescope. Every time we went through a sunrise or sunset, there was a thermal issue with how they were made. And so, uh, that was, as I recall, that was actually the highest priority on the first servicing mission was to replace the solar arrays.


It wasn’t even to, to, uh, install the CoStar, however, after the arrays were deployed. On the first servicing mission, they developed what we referred to as static twist. And there was great concern that if they were jostled too badly, they might actually that’s that twist might be exaggerated to the point where the solar arrays might fail.


Normally the plan is to roll up the solar arrays. After you capture the telescope because that provides a lot more room to maneuver with the arm and the EVA astronaut on the end of the arm. But we weren’t going to be allowed to do that on the servicing mission. They were too concerned that the arrays would be damaged.


And so we knew going in that we were going to have to do all of the tasks with the solar arrays extended, which made kind of the planning and execution a little more challenging. One of the memories I have as we approached the telescope to capture it was as we got close enough, to be able to tell, I thought it looked kinda old and weathered and ragged.


I was a little shocked, frankly. Yeah. It had been in orbit, you know, seven years or so, but, but I was surprised at how weathered it looked, you know, space is a harsh environment and, and Hubble showed the effects when we got close. Enough to inspect it after capture, there are places on the handrails that are, were yellow to provide a clue to the EVA guys that this is a place it’s okay to grab with your hands.


They look scorched. There were places on the telescope itself on the side that preferentially faces the sun where the thermal insulation, the silver, uh, that you see in the, in the images. Had peeled away. And so none of us expected that. And so it kind of looked a little bit worse for wear, although none of that was that had any effect on how it functioned.


It was still functioning fine as far as anybody could tell. But I was, I remember being surprised at how, how it looked when we got close enough to be able to really see. You mentioned earlier in our conversation the great create observatories program, you not only had your hands in the release of the Hubble space, telescope view also played a role in the launch of the Chandra x-ray observatory.


How is that instrument different from Hubble? And what was that launch like compared to Hubble? The Chandra x-ray observatory, of course, as the name suggests is designed to observe x-rays. And so, you know, in a sense, I guess, you know, at some level it functions the way HST does because it takes imagery and it does spectroscopy, but it does it in this very high energy regime, which is not something that you can do from the ground.


So all of the great observatories contributed in a way like, like trying to do a puzzle. And each of the great observatories is designed to produce a certain set of the puzzle pieces. And if you get enough of the puzzle pieces, then you can put, put them together and figure out what the picture of the puzzle is supposed to be like.


And so the idea was to be able to observe. Uh, across the electromagnetic spectrum with all of these observatories, Chandra being the third to be launched. Now, in terms of the launch itself, it was totally different. We carried Chandra to orbit attached to a pair of solid rocket boosters called the inertial upper stage.


And our job was to. Release the Chandra inertial upper stage combination. And then the, uh, inertial upper stage would do two different burns and put the Chandra in an orbit. That would take it a third of the way to the moon. So it’s in a big elliptical orbit as opposed to HST, which is in a roughly circular orbit, lower earth orbit.


Interestingly, Chandra. Back when it was called AXAF, which stood for advanced x-ray astrophysics facility was designed to be serviced at low earth orbit lake HST. However, there was a big budget cut in 1992, and the program decided that in the interest of saving money, the best thing to do would be not do servicing.


If you’re not going to do servicing, then there’s no reason to leave it in low earth orbit. And so you could put it in a, this highly elliptical orbit, which would give it a little more observing time everywhere, but then if it were in lower earth orbit. And so that’s one difference is that HST is serviceable and Chandra.


By the time we launched, it was not. Why are Chandra is visuals and discoveries. So relatively unknown to the public when compared to what we’ve seen from Hubble. Yeah. That’s a question that I’ve wondered about myself. And I don’t know that I have a really good answer to it. It’s possible that because Hubble was first, it got all the attention.


Um, it’s also possible that. Hubble was in the public view for a long time. First of all, because of the problem with the mirror, but over the time period from 1990 to 2009, because periodically astronauts and the space shuttle would go back to Hubble and that would, there’d be usually some drama associated with, with whatever they were doing.


There’s also a Program from the very beginning, as I recall, uh, something called Hubble heritage and what that program was designed to do was specifically to find just visually stunning images and release them to the public. And sometimes the Hubble heritage folks would do that by looking at images that had been taken for some scientific purpose.


An investigator had a reason to study this particular galaxy. And so he took a picture and they decided this picture is really beautiful. So we ought to release it as. As a Hubble heritage image. Um, sometimes occasionally probably not very often. I don’t know the frequency, but sometimes they would get to take a picture specifically because it was going to be really visually exciting and something they could release.


So they had this focus on finding and releasing stunning images. And I don’t actually know whether. Chandra had a, an equivalent program. So I really don’t know for sure, but I would agree that it doesn’t seem like the Chandra imagery, uh, has gotten as much public attention as the Hubble imagery. I asked you the question early on about how Hubble has changed our view of the universe.


Let me ask this now with Chandra, how has Chandra changed our view of the universe? The physical processes that give rise to x-rays that Chandra observed are associated generally with, with what I would say are kind of bizarre events, bizarre objects, black holes, neutron stars, quasars. And so I would say Chandra has told us a lot about the more bizarre objects.


In the universe, black holes, one of the things it did early in its on orbit lifetime was to study the supermassive black hole at the center of the Milky way. One of the things we’ve discovered in the last several decades is that. Most perhaps nearly all galaxies have a supermassive black hole at the center for active galaxies.


A lot of the ones that Chandra looks at these black holes can be billions of times the mass of the sun. I think people were surprised. To discover that the Milky way has a super massive black hole, although it’s only four or 5 million times the mass of the sun. So it’s not as supermassive as the ones we commonly see, but Chandra has been looking at it and watching how the environment around our own supermassive black hole changes.


And in particular, as you know, objects get near the supermassive black hole every once in a while. You’ll see evidence. They’ve been disrupted by the supermassive black hole. You’ll see an x-ray brightening, uh, associated with an event like that. And it’s something we had speculated probably happens, but Chandra is able to actually observe those kinds of things.


So we’re really learning a lot more about these bizarre objects, black holes, neutron stars. One other thing I would mention just because it’s a relatively recent Chandra discovery. I, and I remember telling my students when I taught a class on astrobiology. So we were talking about planets around other stars and how we look for them that there are probably lots and lots of planets in the universe.


Lots of lots seems kind of silly to say, but I don’t know how to quantify it, but we’ll never really know because I didn’t see how we would ever discover a planet around a star in another galaxy. It’s hard enough to do it in the Milky way. Well, it turns out about a month ago, Chandra observations, hinted at a planet around a binary system and a galaxy called M51.


So in another galaxy. And I’ve thought, well, that’s totally bizarre. But the discovery was made in a similar manner to how things like Kepler and TESS do it, which is you look at the brightness of a star. And if it has a planet and the orientation is, is proper every once in awhile at some frequency. The planet will pass between you and the star.


And it will block out a little bit of the Starlight. Not very much, but enough if your detector is physically sensitive to be able to see it. And that’s how we now commonly find planets around stars in our galaxy, it’s called a transit event. Well, there was a neutron star or a black hole. In this galaxy M51 and it had a close companion in orbit around it.


And the companion was shedding material that was kind of falling into the neutron star or black hole and releasing x-rays. And Chandra could observe that, but the place where the x-rays was coming from was fairly small. And what the observers discovered was that the x-rays would get Basically go away for a short time, which could be because there’s a planet orbiting that binary.


And if that turns out to be confirmed, then I’d have to say I was wrong and we actually can find planets around stars and other galaxies. Right now. That’s just a hypothesis. I don’t think people would say that’s confirmed, but it’s intriguing. We are about to open a new era of astronomy with the launch of the James Webb space telescope, this telescope eclipses in size, even Hubble.


In fact, it wouldn’t fit in the shuttle bay. It’s being launched on board and Ariane rocket, uh, which is one of the heavy lift launch vehicles we have here on this planet. Besides the size of the Webb telescope. How is this telescope different from its predecessors and how is its mission different? Yeah.


Um, well, first of all, it’s designed specifically to look in the infrared part of the electromagnetic spectrum. And the reason for that is that. Due to Hubble observations. And now this new generation of ground-based observatories, we have reason to believe that galaxies, the first galaxies formed, formed less than a billion years after the big bang.


And so somehow before those galaxies formed, The first stars must have formed, and we’ve never seen something for sure that we would say is one of the family of the first generation of stars ever created their light would be so. Red shifted due to the expansion of the universe, that you would only be able to detect them with the large telescope that is sensitive and infrared.


And that’s what James Webb is. It’s designed specifically to look for highly redshifted galaxies, which might be the first galaxies formed in the universe, highly redshifted stars, which might be the first stars ever formed in the universe. So that’s very exciting. The other thing that’s different about it is to fit in the.


shroud of the Ariane and it has to get all folded up and it’s going to a location beyond the moon. And so everything that needs to happen to make the telescope functional has to happen automatically. So the mirror itself has to deploy and come together. The sun shield that protects. The telescope from the heat of the sun and the earth has to deploy properly.


And that’s, you know, we were there, fortunately, when we deployed HST, if something had gone wrong, we were prepared to go try to fix it. There won’t be anybody there. To be able to fix JW. If all of these things don’t happen just as they’re supposed to. So, and all of that’s going to take something like a month to go through all of the deployments necessary.


And so I’m probably going to be really nervous for I’m sure it can be a lot of people there’ll be really nervous for, for 30 days while all this is taking place. A billion things have to go right over a month. Yeah. So, and maybe it will, I mean, it’s been tested, it’s just, you know, it’s, it’s scary knowing that there’s not much you can do.


When I was still at NASA, I had suggested that we put on JWST something called a grapple fixture. The grapple fixture is what’s on HST that allows the robot arm to capture it. It’s basically just a pin that’s designed to Work with a mechanism at the end of the robot arm. It just seem to me that if you had a way to grab it, you could, you know, you could at least send maybe some sort of a robot that could shake the thing.


Uh, if the deployment didn’t go properly, I don’t think they took my advice. But we’ll see, hopefully it’ll all work well. So you mentioned early on in our conversation that the discovery that, uh, surprised you the most was the one that the, the Hubble director was able to take some of his reserved, allotted time and point Hubble to a particular direction and make that particular discovery.


If you were the mission director for James Webb, What would you have it focus upon and why? Well, I like the prime mission as it’s been designed that is to look for the first galaxies and stars in the universe. The other thing that can do, which would be very, very interesting is take the results from the test satellite, which is the transiting exoplanet survey satellite.


That are looking at stars that are relatively near the earth for planets. And if they find some candidates that look promising, then James Webb could study the atmospheres of those planets. And look for biosignatures. For example, if you were able to detect oxygen in the atmosphere of a. Planet around another star.


That would be pretty good evidence that there must be life there of some kind there’s water, vapors already been detected in some atmospheres of, of exoplanets. So James Webb would be uniquely capable of probing nearby exoplanets for signs that might be more suggestive of the existence of life. Then we’re able to do, uh, with current technology.


So in the future, when there’s a Hawley space telescope, what would its mission be? Well. One thing I would, I would point out is that it can change the rules, I guess, but traditionally they won’t name a telescope after you until you’re dead. So I hope the Hawley space telescope doesn’t come along too quickly.


Well, we don’t want to see that happen either. Um, and again, not trying to. Again, meaning no disrespect whatsoever. Let me offer this then let me rephrase the question. If you have your very own space telescope and you get to design it and plan its mission, and we’ll name it after you. But what I would do today, People are talking about James Webb as the successor to the Hubble telescope.


And in a sense it is because it’s the next great space-based observatory. However, scientifically its mission is different. And so when the day comes that Hubble is no longer functional, we won’t have something that can do what Hubble does today. So I think if I were designing. A, telescope and a mission, I would want to design the true successor to HST that would build on what HST has done, maybe with the wavelength coverage that HST has, but you know, maybe a little bit larger.


Of course the instrumentation will be better in the years to come so that we can continue. The legacy of Hubble with a Hubble 2 that is an upgrade, but can do, can cover the wavelength range that that HST can cover today. Dr. Hawley, this has been a fabulous conversation. This is a, this has been one I’ve been very much looking forward to, unfortunately what our listeners can’t appreciate that I have.


Besides being able to see you, is that in Dr. Hawley’s office, he has a wonderful print of the Hubble being released from the shuttle bay. Uh, so he gets to see his handiwork literally lift off. But, uh, the other piece is the Jayhawks emblem and a basketball. So we know where his heart is when March madness comes around, but we know your heart is also into astronomy and very grateful for the time and the personal experiences that you shared here.


This has been great for our Space4U listeners, Dr. Hawley, thank you for your time and joining us. It was my pleasure. Thanks again for giving me the opportunity. And with that, this wraps up this episode of our Space4U podcast. We’ve been joined by Dr. Steven Hawley, a noted astronaut astronomer educator.


And what I will always say, someone whose heart and mind are among the stars. We are grateful to him. We are grateful to you, our listeners, and to everyone who supports space foundation, you can find more about us at Join us there. Follow us on social media. And if you would be so good, please give us a five star review wherever you listen to podcasts, because at space foundation, we always have space for you.


Thank you.

Listen to the Podcast

Space4U Podcast: Steven Hawley — Former NASA Astronaut, Hubble Space Telescope & Chandra X-ray Observatory Missions