NASA's Curious Universe - Roman Series: The Technology Inside NASA’s Newest Space Telescope

Episode Date: August 25, 2026

What makes NASA’s Nancy Grace Roman Space Telescope a powerful tool with an unprecedented wide view of the cosmos? NASA engineers who designed, built, and tested Roman pop the hood to explain the unique technology inside. Go inside the huge NASA clean room where Roman was built, and get an up-close look at the testing campaign that ensures Roman will succeed in the cold, inhospitable conditions of space.   Learn more about the Nancy Grace Roman Space Telescope at nasa.gov/roman

Three, two, one. This is an official NASA podcast. You're listening to NASA's Curious Universe. I'm Jacob Pinter. NASA is launching a new space telescope that will change the way we see the universe. It's called the Nancy Grace Roman Space Telescope. Roman will study some of the biggest mysteries out there, answering questions about how the universe has changed over time,

what's driving its expansion, and the worlds that exist. beyond our solar system. Roman has a unique ability to survey vast areas of space with incredible speed and detail. It will collect huge amounts of data, including more than a billion galaxies, and help discover thousands of planets orbiting distant stars.

Roman will join other space telescopes, including Hubble and Webb. It builds on NASA's technology and know-how that have shaped our view of the cosmos for decades. In this episode, the technology inside Roman and how NASA prepares a telescope to go to space. We'll visit a special test facility where NASA creates the cold vacuum of space right here on Earth. And we'll get up close with Roman with a few of the engineers who make it possible. We're going to start this story in summer 2025.

Roman at this point is already years in the making. It's almost fully assembled. For now, it's in two pieces, for the final stage of testing. And then those two pieces will be joined together. Now, I typically only get to see Roman from afar, through a window. But I am allowed to get super close this time

because I'm with an engineer named Ashley Wilhelm. I guess you're probably recording me right now. I am. We can talk about this. Ashley points out something most of us might take for granted. Roman is big. Almost everything that we have to do now is a big operation.

We need scaffolding to work on this structure because it's so big. Like, I can't just go up there and touch it, not because I can't, but because I'm not tall enough. Ashley is a mechanical engineer who helped design, build, and test parts of Roman. In its final form, Roman is about as long as a semi-truck trailer. It's 42 feet long and 14 feet wide. Fully fueled, it weighs more than 20,000 pounds,

at least until it becomes weightless in space. The part that we're looking at is sort of like Roman's exoskeleton. Across the room, the other part has the telescope optics, science instruments, and other sensitive equipment. Mounted on this exoskeleton is an array of orange and black solar panels. On this day, they're arranged in a way that reminds me of a crown, framing the outside of Roman. This section of the telescope is on a work platform, maybe 15 feet off the ground. So the whole thing looms over us. Having to move something that weighs so much and is that large and that, I mean, we do several

tests, I don't want to say fragile, but like that important, people have put so much work into it is definitely very interesting and something I don't know if I'll ever be able to, like, experience again. Ashley actually started working on Roman remotely. She was an intern during the summer of 2020, but even then, she was working on tests for individual components of Roman. She has seen the telescope get bigger and bigger. Yeah, we can also walk around the whole thing and I can like... Yeah, can we? Yeah, yeah.

I don't want to go anywhere I'm not supposed to go. Just don't touch it. Yeah, I'm not going to know. I'm not touching anything. Yeah, okay, so this is the front. So now I guess you guys have a lot of... Here is a very quick rundown of what's going on inside Roman. Roman studies the universe by collecting light.

Its primary mirror is exactly 7.9 feet across, or 2.4 meters. the same size as Hubble's mirror. Roman has two science instruments, and in other episodes of this series, we go into much more detail about the science questions it's designed to answer. In addition to being a telescope, Roman is a spacecraft.

It has a propulsion system and fuel tanks, as well as miles of cables for electricity and communication. Of course, Ashley sees it in much more detail than what I just described. NASA projects are full of acronyms. I like to think that I'm pretty, good at decoding them. But talking to Ashley, I realize there are levels that I will just never reach. So that's comprised of Oba, which is the main structure of OSCE.

Then we have DAC. The main point of DAC is to kind of shield the way. Then we have SAS, which are the main solar panels, which will also... Then we have Skippa, which is sitting over... Skippa has H-gas within it, which is the high-gain Tena system. and then the IC, which is holding both of our instruments and the telescope. How long did it take you to learn all those acronyms? Honestly, it really comes with time. And there's some acronyms like the cystiff that I still don't know what it stands for, but it's totally fine.

Now, there are going to be some acronyms throughout this episode. We'll break them down as we go. Starting with the one that Ashley just said, Sistif, spelled S-S-D-I-F. This is an important one because it's still. the formal name for the room where Ashley and I are talking. It stands for spacecraft systems development and integration facility. I had to look it up. Most people just call it the clean room. Dust and dirt and contamination of all kinds are the enemies of a space telescope. There are actually a lot of materials that could damage the sensitive technology inside Roman.

So there are tight rules around what you can bring into this room. There's a whole long list of these kind of things, even like your everyday paper or your everyday, like, markers. They're not coming into the clean room. For like a preth of reason, some of them is, you know, if you rip your piece of paper, there's going to be like particles coming off of that. The clean room where Roman was built at NASA's Goddard Space Flight Center in Maryland is the largest clean room of its kind in the world. It's massive, eight stories tall with enough floor space to fit two.

basketball courts. Inside this room, it is exactly 68 degrees Fahrenheit and exactly 45% humidity. There's a carefully calibrated air purifying system that is constantly circulating clean air. An entire wall of this room is an eight-story grid of air filters, which can filter out particles as small as a red blood cell. Every person who enters the clean room has to wear an outfit nicknamed a bunny suit. Any small fleck of skin or stray hair or anything else that could come off of us could be a hazard for something going to space. In a prep room on the way in, a few machines blast you with air to get off any loose particles. And then everyone in the clean room wears the same baggy white gown.

There's a hood covering your hair, a mask and gloves like a surgeon wears, and little booties that cover your street shoes. All of this was a little intimidating. I didn't want to be the guy who broke the Roman Space Telescope. And even though Ashley is now a regular in the clean room, she also remembers her first time walking in here. Before her first real day of work, she did a recon trip with another young engineer. And we were so nervous coming in and we're like,

hey, we're going to mess it up or we're going to forget a step or somehow we're going to be confused and left in the dark even though we've done all the appropriate training. But it is kind of something that's super exciting. It's such a big room you look up and you could get dizzy just staring upwards almost. Just coming into such a big space to work is absolutely incredible. Being next all of these just massive structures and knowing that you're going to be a part of putting them all together is pretty exciting.

Everything in this room is designed to make it easier to handle big, sensitive equipment. So the clean room has its own built-in cranes, two of them. Part of Ashley's job is being a task conductor for crane lifts. These lifts are a team effort. When it's time to use the crane, Ashley directs the team and helps them move as one unit. So I'll be telling people, okay, this is where we're going to take the bolts out of its current mating surface. This is how we're going to fly it over there, and this is how we're going to bolt a pack up together. For Roman, Ashley was part of one memorable crane lift.

One of the tests Roman goes through is in a facility called the Space Environment Simulator. And just put a pin in that because we're going to come back to it later. This is a large chamber, a few stories tall. But this part of Roman that we're looking at, the exoskeleton, is so big that it just barely fit inside. Ashley was there, talking everybody through it. We had inches on probably three different sides of the structure at any given time that were inches away from chamber wall,

which if you've ever worked with a crane, an inch isn't that much. And just being able to, like, stay calm as we're moving the whole structure around so it doesn't hit the wall. I mean, obviously you don't want your whole spaceflight structure to hit the wall and it didn't. But it is kind of like a high-stress situation

that the whole team that you're working with has to be very much on their game. The huge task of putting together a space telescope is made up of lots of small moments like this. Teams of people, bring in their A-game, and working together to deal with whatever problems get in the way. These teams build up kind of a funny rapport.

In the clean room, everyone's body is completely covered by the bunny suit, even their face. So you learn to recognize people only by their eyes and the way that they walk. Ashley says working in the clean room can get tiring, especially how dry the air is. After long days in here, she'll have dry skin, she has to remember to take water breaks. But it's worth it. Sometimes we'll be in here for like 12 hours a day working and it does get a little bit tiring, but I don't want to take it for granted. It's pretty cool. Now, I can't stress enough that every NASA mission is a huge team effort,

especially something as complex as Roman. Just to give you an idea. One of Roman science instruments was built in Colorado. The other was built in California. A company in New York got that 7.9-foot mirror ready to go. foot mirror ready to go, and it was all assembled and tested in Maryland. There's a window that looks into the clean room, and people go look at Roman all the time. My office is just right outside the viewing area, the clean room window viewing area,

and so every day I get to walk in and see it. Mark Melton is the mission systems engineer for Roman. When those pieces all started coming in and that clean room was packed, I mean, that's a huge clean room, and it was packed. and you're like, wow, this is really coming together. Mark has been involved with Roman from the very beginning, 2008. At that stage, NASA was still figuring out what this mission was going to be. There was a proposal to study dark energy.

Dark energy is a mysterious force that shapes the structure of the universe. It's one of the biggest mysteries that astronomers want to solve, and we go into much more detail about dark energy in another episode of this series. Anyway, at that stage, there were lots of meetings and PowerPoints. Scientists and engineers don't necessarily speak the same language, but they had to work together to define requirements. What must the telescope be able to do? There wasn't one clear path to take.

They had to figure it out. We had lots of kind of one-on-one meetings with our internal scientists to help us understand how to translate a really technical science requirement that, you know, I have no idea what it really means initially to, first of all, something that I could understand and understand what meeting that requirement might imply on how the hardware on the spacecraft and the instruments and telescope have to function. Did you have a sense at the time, like, this is a big opportunity for me personally? Not necessarily. I wasn't the lead in the beginning, you know, as an engineer,

working at NASA, you just want to do the best to, you know, get the best science for your scientists, right? I mean, everyone's always awed by the images we see, and that's super cool. But, you know, they're digging into that data and coming up with amazing understanding of how the universe functions. So that's what we focus on. But even with that goal in mind, it takes patience to be in Mark's shoes. NASA missions might be the ultimate example of measure twice. cut once. Roman will sit on top of a rocket, fly into space at tens of thousands of miles

an hour, travel a million miles away, and all of its delicate systems have to stay intact. If something goes wrong, there are no second chances. There are no plans to go rescue it. So everything has been meticulously planned for years. And Mark was there the whole time. So I asked for his help understanding what makes Roman so powerful, starting with its detain with its detectors. These are essentially little cameras. They make it possible for Roman to capture its wide view of the universe. Roman has 18 of these detectors, and they combine to create the equivalent of a 300 megapixel camera. It's not like these are a factory where you just have an assembly line and they're just spitting them out, right? These are kind of custom build for us.

Roman's detectors build on NASA technology that's gotten better over the years. The Hubble Space Telescope has detectors that are 1,000 pixels by 1,000 pixels. NASA's James Webb Space Telescope is 2000 by 2000. Roman has scaled it up to 4,000 by 4,000 pixels in a package that's a couple of square inches in area. That means the space between each of these pixels is just a fraction of the width of a human hair. More pixels means more detail in the images Roman collects. An HDTV is 4K by 2K. We're twice as many pixels of that in, like I said, a two to three square inch area.

And we have 18 of those put together. So when you have 18 of those, you get this massive field of view. And that's really the game changer is those detectors. Next, to achieve its science goals, Roman needs to be super stable. Engineers have to minimize something called jitter. If you've ever tried to take a picture on your phone and you couldn't hold it steady or someone bumped into you when the photo turned out bad, that is jitter. One way Roman cuts down on jitter is with its solar panels.

They don't stick out very far, and they're stiff. A lot of people maybe have seen a satellite with a huge, long solar race sticking out the side. I mean, you can imagine if you move, those are going to flap like bird swings, right? and that's just going to induce kind of vibration into the satellite. So we minimize anything like that that can really vibrate. In space, heat can also affect stability. Temperature changes can make things expand and contract. After it launches, Roman will not stay in Earth orbit.

It will travel much farther away, even beyond the moon, to a point in space called Lagrange Point 2. This point is a million miles from Earth, and it's kind of a gravity sweet spot where Roman can stay in a steady orbit. And that has some advantages over sticking close to Earth. When you go around the Earth, every 90 minutes you go in and out of the Earth's shadow. So you're dramatically changing your temperatures, which you could make things shift. So we're a million miles away where we don't get any shadows.

And then we have a very fine temperature control where we're trying to control things to tens of a degree, or even in some cases, hundreds to thousands of a degree. With its super HD detectors and that ultra-stable precision, Roman will not only see lots of the universe at once, it will be able to move quickly between observations. It will also collect a huge amount of data. Mark described a process that kind of sounds like autosave. If Roman is supposed to be taking a picture every two minutes or so, it has a feature that actually takes a picture every two and a half seconds, just in case. Getting all that data back to Earth is its own challenge.

We have a massive antenna. Our antenna is about 5 feet, 7 inches in diameter, and we're just pumping data down. Every single day, Roman will send us almost a terabyte and a half of raw science data. Take a look at the hard drive on your computer and see how many days of Roman data you could fit on there. Probably not many. Throughout its five-year mission, Roman will collect

more than 20,000 terabytes of data. I've heard someone on the Roman team say that this will be more data than the catalog of an entire music streaming website. Now, all of these engineering plans that Mark just described, all of these technology marvels, they've been around as plans and computer models for a long time. But it was only in the past few years that Roman really took shape. September 2020, the primary mirrors. finished. September 2023, Roman's wide-field camera is done. In 2025, technicians add a sunshade

to keep unwanted light out of the telescope and those solar panels for power. And then, on November 25th, 2025, NASA completes construction. The final two pieces of the Roman Space Telescope are joined together. When those got put together, a huge crowd outside watching that, and it was three, thrilling, so exciting. And I went back to my office and I sat down and I got a little tear in my eye and I kind of choked up. I'm like, wow, it's actually together now. And it really like just like sunk in like after all these years.

We have, you know, the one thing together now that we've been working on. It was kind of mind-blowing to me. Why was that powerful enough to make you cry even? I mean, it's been almost 20 years. It's half my career on this one thing. And, you know, the excitement in the science community, every time we talk to scientists, they just can't wait. It's just thrilling to be able to get to a point where we can provide this tool for them. You know, it's really it's unlocking the mysteries of the universe.

It sounds very grand, but that's what they're going to do. I mean, it's crazy. But even then, the work isn't done. Because after they've built Roman, NASA engineers have to be able to. to make sure it's ready to survive in space. Putting together is one thing, right? It takes a couple of years to put it together, but then we take another couple of years

to test it like crazy to make sure that it's going to do everything that we expect and work hopefully well beyond the five years that we've designed it to do. Now, we're going to jump back in time a little bit, back before the telescope was fully constructed, back to the same era as when we met Ashley in the clean room, with the telescope in two major pieces.

And that is when I meet another NASA, engineer named Matt Stevens. Okay, so we are right now in the integration of test facility at Goddard Space Site Center here in Greenbelt, Milderden. Matt is an aerospace engineer at NASA Goddard. And we're heading down the facility to our large thermal vacuum test chamber. We call it T-VAC for short. How did you get into this line of work?

Have you always wanted to, you know, throw stuff into space? Uh, short answer, yes. While we walk, I'll tell you a little about Matt. He's one of those people who had a pivotal meeting with a guidance counselor that just changed the course of his whole life. In seventh grade, his counselor helped point him toward aerospace engineering. He started down that path and never looked back. Matt grew up not far from NASA's launch site in Florida. He remembers his teachers taking all the kids on the playground to watch space shuttle launches.

So the seed was planted early. And growing up in Florida, I thought that was normal. So it wasn't until later in life that I found out how unique and really how amazing that was that I got the ability to see that and be exposed to that growing up. The facility that we're walking in, the integration and test facility, must seem to an aerospace engineer like a candy store or six flags. There are all kinds of huge, specialized tools that mimic extreme conditions of spacecraft. must survive. There's a vibrational table, large enough that you can put an entire space telescope on it. It shakes in a way that mimics the vibrations from a rocket launch. Launches are also incredibly loud, so there's a test chamber for that. It's a tall, rectangular

room. The ceiling is a few stories high and there's nothing on the walls, so they are extremely echo-y. There are these huge speaker cones mounted in the wall, and they blast the telescope with preposterously loud sound waves. Tests like these are the only chance to measure your spacecraft and make sure it's really as good as you think it is before it goes out there for real. If you're buying a car, that's what you're going to do, right? You're going to go, the car dealership's going to give you the keys.

They're going to let you drive it around a neighborhood. They're going to let you drive it on the highway. And you get the luxury of test driving that on a road in the environment you're going to use it in. But in space, we can't do that. We can't test drive a spacecraft in space. So what we do is we do these different tests here on ground to try to simulate that space environment. The saying that you hear over and over from NASA engineers is test like you fly, fly like you test.

Every step of this process is designed to get as close as you can to what the spacecraft will experience, even though creating true space conditions is usually impossible. I'm here with Matt because Roman is going through a test as we speak. It's inside a huge stainless steel chamber called the Space Environment Simulator. From the outside, the chamber is just a silver behemoth. It's a few stories tall, so tall it actually extends down into the basement below us. It's shaped more or less like R2D2, and it has all kinds of pipes sticking out of it. Inside the chamber, Roman is getting a little taste of its life in space.

So we're going down to really cool temperatures. Okay, for this test, we're going down to about 140 Kelvin. That's about negative 130 Celsius, about negative 200 Fahrenheit. I believe that's colder than any place on Earth. So we're talking about really low temperatures here. Things you can only achieve in space. As Matt talks, you can hear a lot of pumps whirring in the background. In a nutshell, this chamber's job is to pull out air and energy and not let them back in.

Once the part of the telescope being tested is lowered into the chamber, Through the same kinds of cringlifts we heard Ashley talk about earlier, the test starts by gradually pulling out the air. Those is hooked up to a different type of vacuum pump. Some of them are roughing pumps, some of them are turbo pumps. Then there are large metal plates with liquid nitrogen running through them. Those actually help radiate away energy from the telescope, which brings down the temperature. I mean, we're artificially making space in there, right?

We're making a vacuum. We're making the temperatures. We're doing everything we can but turn off gravity because we can't do that, right? Now, while one team is creating the space environment, another team is monitoring the telescope. For this test, engineers make sure Roman's optics perform the way they expect. As Matt and I talk, we get about as close to the chamber as we're allowed to. There are yellow lines on the floor and barriers marking the places we're not supposed to cross. But Matt has been even closer to this chamber. He's actually been inside.

Not while it's making space conditions, of course. Before a test starts, team members have to head inside the chamber to get things ready. And inside it's pitch black because a black paint helps absorb that radiation from the spacecraft and cool it down. So you walk into this room, you're wearing a white clean room suit, and you're standing in blackness. Okay, and this chamber is made to simulate space. So you're staying in this chamber where you know in a few days there's going to be nowhere. You know it's going to be negative 200 degrees Fahrenheit. This stage of the process, according to Matt, is super rewarding.

He has seen computer models of Roman for years. And then, all of a sudden, it's real. He can see it in front of him. And he gets to put Roman through its paces, making sure it's ready to go explore the universe. Now, does every day feel like such a treat? Not necessarily. Working in the space environment simulator can be uncomfortable.

It's tight quarters, and sometimes you have to, shimmy around scaffolding and ladders. It's ventilated for health reasons, but it's not ventilated for comfort reasons. So it gets pretty hot in there. So after a few weeks of working in there, you start to lose the magic and you start to get ready for that test to be ready and be out of the chamber. But every time you go in after you get ready for a new campaign, you get back in the chamber, there always is that initial kind of excitement there.

It's just about how amazing this step of the project is. and how you're getting one step closer to that goal of getting it into space. On the other side of this test, Mark Melton was also keeping a close eye on Roman. He was one of the people making sure the telescope performed well. This was a 24-hour-a-day job, with teams of engineers rotating through, even at odd hours. We literally had probably 30 people at a time at least on shift 24-7. And yeah, so you just, sorry, honey, here's my schedule for the next two months. You know, midnights are never fun.

But you learn that's part of the job, and you just, you roll with it. After this testing campaign, NASA knows Roman is ready to go. Because engineers tested Roman like it's going to fly, and they're going to fly it like they tested it. We're building one-of-a-kind satellites. It's never been built before. no one's going to build this again. And so you do the best you can to design. You always find little things that don't quite go the way you expected it.

Part of our testing, we like to say, is learning how the thing that we built works. Along with the testing program, NASA has a series of reviews throughout the life of the mission. These are check-ins to ask, is the plan still on track? And is the mission going to work? When I talked to Mark, he was looking ahead the one of Roman's final reviews. The day when he would have to stand up in a meeting and report to NASA's top leadership

that Roman was ready. That after everything, the years of design and construction and testing and the many hands who touched it along the way, Roman's time has come. We kind of affirm that we're ready to go, that this mission, we've done all the right things. any issues we've had, we've addressed whatever risk are remaining.

We think we've reduced to as minimal as possible, and, you know, we're good to go. Sounds like a big day. Yeah, I always joke with my deputy. I'm going to be sick that day. You're going to have to do that meeting. I don't know what day it is, but I'm going to be sick that day. But no, I mean, you know, I said we've put the thing through its paces. So when launch day comes, when it's on the launch pad and the rocket begins,

to fire and there's no turning back. Roman will be ready. We've done everything we can to make sure this mission will be a success. So it's a big thing to say, but, you know, I believe it. We've done the work. For a few months after Roman launches, Mark will be on the team that brings it online. This stage is called commissioning. Mark will be a flight director on a team with 24-7 staffing.

So he might be back at work at midnight again. When Roman starts sending back images, then the hours get back to normal. And like the rest of us, Mark will be watching, waiting to see what Roman discovers in its wide field of view. Roman will probably be known for something, you know, 20, 30 years from now, answering a question we haven't even thought to ask yet, which is kind of crazy to me. So it's kind of thrilling to be able to say, I played some small part in answering some big science question. Thanks for listening to NASA's Curious Universe. The Nancy Grace Roman Space Telescope is scheduled to launch no earlier than August 30th.

You can find launch information and the latest news about Roman at NASA.gov slash Roman. NASA will live stream the launch and you can see the full broadcast at NASA.gov. Then, after launch, stay tuned for more information about Roman's journey and the release of its first images. Again, that's NASA.gov slash Roman or follow along on social media at NASA. This is NASA's Curious Universe, an official NASA podcast. This episode was written and produced by me, Jacob Pinter. Our team also includes Christian Elliott. Our executive producer is Katie Conan's.

West Buchanan and Christopher Kim designed the show art for this series. Our theme song is by System Sounds. Special thanks to Claire Andrioli, Elise Fisher, Sophia Roberts, and Emma Brembilla. You can find transcripts for every episode of Curious Universe and explore NASA's other podcasts at NASA.gov slash podcasts. If you enjoyed this episode of NASA's Curious Universe, let us know. Leave us a review wherever you're listening right now. Why not send a link to one of your friends? And you can follow NASA's Curious Universe in your favorite podcast.

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