Andrés Almeida (Host): Welcome to Small Steps, Giant Leaps, your NASA APPEL Knowledge Services podcast where we dive into the lessons learned and real-life experiences of NASA’s technical workforce. I’m your host, Andrés Almeida. 

Dark matter. It makes up 85% of all the matter in the universe, yet we don’t know what it is. It’s completely undetectable by any instrument. But scientists can infer it’s there because we can see its gravitational effects on stars and galaxies. 

The Roman Space Telescope, set to launch in 2027, will aim to unravel the mystery of dark matter. With a field of view 100 times wider than the Hubble Space Telescope’s view, Roman will also study the evolution of galaxies, and will set its gaze upon the atmospheres of planets orbiting other stars, making other exoplanet discoveries along the way.

The mission is named after Dr. Nancy Grace Roman, NASA’s first chief astronomer. She’s often remembered as the “Mother of Hubble” for her pioneering role in getting Congress to approve Hubble’s development. 

With us for this episode from NASA Headquarters in Washington, is Dr. Lucas Paganini, deputy program executive for the Roman Space Telescope. 

Host: Hi, Lucas, thank you for being here. 

Paganini: Hi, Andrés, thanks for having me. 

Host: Can you tell us about your role with the Roman Space Telescope? 

Paganini: Well, I’m the deputy program executive for the Roman Space Telescope, and my role is to work with what we call the project team. In this case, the Roman mission is managed out of NASA’s Goddard Space Flight Center, and I’m based at NASA Headquarters, so I serve as one of the interfaces between the project and our NASA leadership team. 

Host: Great. Let’s talk about the basics of Roman. Why is Roman important to science and what are its capabilities? 

Paganini: So, the Roman Space Telescope is named after a pioneering person. She was the NASA’s first chief of astronomy, Dr. Nancy Grace Roman. She’s also known as the “Mother of Hubble,” and she had a very important role in the astronomical community because she understood that observing the sky or any other celestial objects from space was something really important in order to better understand other planets and the universe and how things work in the universe. 

And like Dr. Roman – she had such a strong influence in astrophysics – the Roman telescope will address fundamental questions in astrophysics, cosmology and even planetary science. It actually aims to uncover the mysteries of dark energy and dark matter, study exoplanets and explore the universe’s structure. What is interesting about this telescope is that it has as its primary capability something called a Wide Field Instrument. And this instrument is going to provide a view 100 times larger than Hubble’s, while maintaining the similar resolution. And this will enable [us] to survey vast portions of the sky, making it ideal for studying dark energy, dark matter, and exoplanets.  

And also, one key aspect of Roman is that it’s going to feature something called a technology demonstration, which is a coronagraph, and this is to directly image exoplanets and study their atmospheres, pushing the boundaries of what we know about planetary systems beyond our own. 

Host: It sounds groundbreaking, like many space telescopes, so how will Roman complement Webb and Hubble? 

Paganini: Well, that’s a, that’s a great question. You know, Roman, Webb, and Hubble each have unique strengths that, when combined, offer an unparalleled view of the universe. And together they can provide a comprehensive view of the cosmos, from individual stars to large-scale structures. 

For instance, Hubble excels at detailed high-resolution imaging of specific cosmic phenomena, while web focuses on infrared observations, allowing us to peer into the most distant reaches of the universe. And the cool thing is that Roman will bridge the gap by conducting wide field surveys and uncovering new targets for these telescopes. For instance, Roman could identify potential exoplanets for web to study in more detail or discover galaxies that Hubble can then analyze more closely. I think that, together, these observatories will provide a more complete picture of the cosmos. And the data from Roman’s large-scale structure will help identify targets for more detailed studies by these other observatories. And this is going to create a powerful synergy between these observatories.

And things like the technology demonstration, the coronagraph that is going to be on board the Roman mission, is going to help test very important technologies that are needed for the next generation flagship missions, such as the Habitable Worlds Observatory. This flagship mission, which is the upcoming flagship for the [NASA] Astrophysics Division is going to help us seek for what we call Earth 2.0’s. So, basically, what we’re trying to do is to detect Earth-like planets in other stellar systems (so this is what we call exoplanets) and try to understand if such planets could be habitable. 

Host: So, it sounds like the astronomy community is very excited about all this. 

Paganini: Absolutely. The amount of information that Roman can gather and the data that we’ll achieve is unparalleled. And, of course, the astrophysics community is looking forward to its launch, which is expected not later than May 2027, so we’re in the final stretches of the development phase of this mission. We’re actually about to start Phase D, which is everything related to the assembly, the integration, and testing of the observatory before its launch in 2027. 

Host: Excellent. So Roman’s capabilities are to look at exoplanets. What do astrophysicists currently know about exoplanets and also dark matter? How about that? 

Paganini: Yeah. Well, let’s start with you know, dark matter, dark energy. You know these are two mysterious components of our universe that we know exist but we don’t fully understand. Some interesting fact that I can tell why they’re important is that everything we see – stars, planets and galaxies – all of that makes up to less than 5% of the total universe. This means that together, dark matter and dark energy make up about 95% of the universe. With dark matter I estimate it to be around 27% and dark energy about 68%. So understanding them is crucial for grasping the overall structure, formation, and future of the universe. 

So let’s talk a little bit about dark matter. You know, dark matter is a type of matter that doesn’t emit, absorb, or reflect light. So basically, it’s invisible, but it’s detectable only through its gravitational effects. So imagine that we cannot see it directly, but we can see how it interacts with that other 5% of matter we can observe. 

So you may ask, “Why do we think it’s there?” And this is an interesting finding. Some time ago, scientists noticed that galaxies spin, spin faster than they should based on the visible matter they contained. So this suggests that there’s extra invisible matter holding them together, which we call dark matter. 

I always try to link this to…remember we when we were kids? This game that, you know, kids hold their hands and there’s always a leader that that sort of, like, turn around with all the other kids holding hands, and this essentially accelerates the tail, right, of the people in at the at the end of the tail? And if you’re not hanging on strongly, you fly away, right? And this is the same with galaxies: You know that there are stars, but if there’s not enough mass, some stars at the end of this, the outer skirts of the galaxy would fly away. So essentially, dark matter acts as the hands. 

So we can see there are kids in that line, but we, with the capabilities we have, we cannot see them holding their hands together. So this is basically what dark matter is. Dark matter acts as this holding of hands. It’s like a cosmic glue holding galaxies and galaxy clusters together, and without it, galaxies would fly apart. Because they spin too fast for the amount of visible matter they contain. 

So again, Roman is going to provide all this comprehensive view of the universe that is going to probably allow us to infer from indirect observations.

On the other hand, dark energy is an unknown force or energy that is causing the universe to expand at an accelerated rate. There were some discoveries in the 1990s when scientists were measuring distances using supernovae (these are basically exploding stars) and they found that the universe expansion is speeding up rather than slowing down. And this unexpected acceleration suggests that something, which we call dark energy, is pushing the universe to expand faster. 

As I mentioned before, like dark energy roughly makes up about 68% of the universe and is responsible for driving the expansion of the universe is, you know, counteracting the pool of gravity on large scales. So in simple terms, dark matter is like an invisible glue that keeps galaxies together, while dark energy is like a mysterious push making the universe expand faster. So, definitely fascinating. I’ve been learning more and more since I joined the project two years ago, on this fascinating topic of dark matter and dark energy. And of course, Roman’s wide field surveys will provide, again, critical data to understand its properties. 

On the other hand, exoplanets is one of my favorite projects as well. Since 1990 also, when we in those years in that decade, we discovered the first planet beyond our solar system – so it’s basically, as I mentioned before, a planet orbiting another star, what we call exoplanets – since then, we have discovered and confirmed over about 5,500 exoplanets so far. And what we have discovered thus far is that they usually have a wide range of sizes, compositions, and orbits. However, there’s still much we don’t know about their atmospheres, formation, and potential habitability. And again, these different instruments on board Roman are going to allow us to advance our understanding of these exoplanet systems. We know that most of the systems in this catalog of over 5,000 exoplanets are mostly gas giants, but this could be due to some of the observational techniques we used in the past. We know that missions such as Kepler and TESS have advanced this catalog significantly, but there’s still a lot of things we don’t know. 

And Roman is going to use two techniques. One is using its instrument called the Wide Field Instrument and it’s going to do microlensing to find new planets, planets, especially smaller rocky planets. And with the coronagraph, we’re going to try to aim for direct imaging of exoplanets of the size of planets like Jupiter. So you might ask why are we not imaging planets the size of Earth? And this is because technically, we’re limited. We haven’t yet developed the technologies to explore or to directly image planets the size and mass of earth. So definitely there’s a lot to learn. 

And something that I think is a fascinating fact and discovery is we now know that [for] each star in the universe, there’s at least one orbiting planet, what we call the exoplanet. And we know that there are billions of stars out there, right, different galaxies and so on. Even within the Milky Way, we have a lot of stars. So that means that if we have billions of stars out there, and we have only cataloged roughly between 5,000-6,000 exoplanets, we have a lot of work to do. 

Host: So how do those science goals that you mentioned, how do they drive the engineering of the telescope itself.

Paganini: So science goals are a core foundation of every engineering decision on Roman and other missions in the [NASA] Science Mission Directorate, where the Astrophysics Division is part of. So basically, it’s goal-driven engineering, right? The science goals dictate the design and capabilities of the instruments. For example, to study dark energy Roman needs, to survey vast regions of the sky with high sensitivity, you know, leading to the development of this so-called Wide Field Instrument. Similarly, the desire to directly image exoplanets led to the development of the coronagraph. So definitely, it’s very important. 

And in this process, I think communication is key, because each scientific objective is translated into engineering requirements, which are then rigorously tested to ensure they meet the mission’s need. And this is an iterative process. Like there’s a constant feedback loop between scientists and engineers to ensure that the instruments can meet the scientific objectives, leading to iterative designs and refinements. And this iterative process ensures that the instruments are finely tuned to achieve Roman’s, ambitious science goals.  

And this is a very interesting dance between, again, science goal goals and engineering requirements that require a lot of teamwork and a lot of communication to ensure that everyone is on the same page and that we ensure mission success. 

Host: No doubt. What project management knowledge nuggets do you use to keep everything flowing that’s a complex mission 

Paganini: So, successful project management on a mission like Roman requires, I think, a blend of technical expertise, science, understanding and strong communication, as I was alluding to before. And it’s very important to define clear milestones, have regular check-ins and a culture of collaboration. I think those are vital, and flexibility is also crucial. 

Space missions often face unexpected challenges, and the ability to adapt while keeping the team focused on the end goal is key. We had some instances, for instance, on the coronagraph instrument, where we have some manufacturing issues with some of the resistors and some of the electronic boards of the instrument and, and that created some, some impact. You know, we needed to come up with new ideas, new solutions.  

 First of all, understand the problem and then have the team did a great job at finding solutions to overcome the issue. They replaced about 14,932 or so resistors and in a very, you know, short time to ensure that they would deliver on time. And that was, you know, a magnificent effort. 

And even with the Wide Field Instrument there was some thermal management that they needed to do on the amazing detector array that they have in order to get these wide field images that it required a lot of thermal management from the time they were testing all the way to the integration to the instrument. And from now till the launch, they’re going to have to keep those detectors under a certain temperature to ensure that they operate as expected when they fly and operate in space. 

But you know, personally, I emphasize the importance of understanding the big picture while paying attention to detail. And like in any team effort, it’s important to ensure that every team member knows how their work contributes to the mission success. Thus, again, communication is key. I think in terms of communication, you know, it’s important to have open, clear, and regular tag-ups between all teams, including science engineering and management teams. I think that’s key. 

So definitely, you know, another very important is risk management. I think it’s very important to identifying risk early, and as I mentioned before, developing mitigation strategy. I think that’s crucial to ensure the mission’s success while staying on schedule and within budget. 

Host: That’s highly valuable. You mentioned the flexibility aspect of project management, aside from challenges that any mission faces. For Roman specifically, are there any new astronomy findings that have reshaped or redirected the telescope’s original science goals? 

Paganini: Well, I would say astronomy is constantly an evolving field and new discoveries frequently shape our understanding of the universe. While Roman’s core science goals – the ones we just talked about, studying dark energy, dark matter and exoplanets – remain intact, recent findings have highlighted the importance of these areas more than ever. 

So, something very interesting about this mission is that we have defined something called core community surveys. And this is basically the Roman has these surveys that are, are a set of large-scale astronomical surveys that will be conducted during the first several years of the Roman mission. And what I find innovative is that these surveys will be defined and led by the scientific community, ensuring that they address the most important and timely scientific questions. 

So basically, the goal is to make the data not only, you know, have this observation made so that it addresses the latest needs from the scientific community, but also, the interesting thing is that the data taken from this mission is going to be publicly available immediately, enabling a wide range of scientific research and discoveries by astronomers around the world. And I think the discovery of more diverse exoplanets has also emphasized the need for Roman’s Wide Field Surveys and direct imaging capabilities. And no doubt the continuous refinement of our scientific understanding ensures that Roman remains at the cutting edge of discovery, and I’m sure that Roman data is going to help us answer these lingering questions, but also is going to set up new questions not yet set and I’m sure that that’s going to help us probably build the next flagships and encourage the next generation of scientists to do new discoveries in the future. 

Host: Excellent. Well, it does sound like we’re constantly in a new era of astronomy. Like it doesn’t get old to say. As you said, it’s evolving. So is that what you hope Roman’s legacy will be? 

Paganini: Yeah, I think, I think that Roman’s legacy will be that of a mission that transformed our understanding of the universe, that bring us closer to understanding what the universe is made of, right? We talked about that 95% of matter and energy, we don’t know quite what it is. So I think that’s going to be revealing, again, knowing that all we know, planets, stars and galaxies represent only 5% of what we can observe is incredible, and that that other 95% we cannot yet understand what is, is mind blowing. But I think also Roman is going to bring us closer to knowing, you know, those planets beyond our solar system. What about those, right? What are they made of? And then answer questions such as, “Is Earth the only planet that could support life?” Or, you know, answering the question, “Are we alone in the universe?” There’s so much we don’t know about.  

And this is one of the beauties of this job at NASA. And, you know, we work to help find those answers. And that’s incredible. That’s incredible. And I hope Roman’s legacy will be one of profound discoveries. Definitely I think that Roman will help us answer those questions. 

Host: Can’t wait. So, Lucas, before we close out here, what was your giant leap? 

Paganini: That’s a great question. My personal giant leap has been the opportunity to contribute to a mission as groundbreaking as the Roman Space Telescope. You know, being part of a team that is pushing the boundaries of what we know about the universe is incredibly rewarding. And as I said before, for me, it’s it’s not just about the scientific discoveries, but also, I think it’s important to inspire the next generation of scientists and engineers. I think that every step we take with Roman is a step towards a deeper understanding of our place in the cosmos, and being part of that journey is truly my giant leap. 

Host: We’re glad you’re part of it. Lucas, thank you for joining us today. Thanks for sharing everything about Roman and your insights. 

Paganini: Thanks so much, Andrés, and it’s been a pleasure sharing with you the amazing things that we’re doing with the Roman Space Telescope and the Astrophysics Division. Thank you so much.

Host: That’s it for this episode of Small Steps, Giant Leaps. For more on this topic and more on Lucas, visit our resource page at appel.nasa.gov. And don’t forget to check out our other podcasts like Curious Universe and Houston, We Have a Podcast. Thanks for listening.