As the 246th meeting of the American Astronomical Society (AAS), held jointly with the society’s Laboratory Astrophysics and Solar Physics Divisions, kicks off in Anchorage, Alaska, this week, scientists and students from the University of Colorado Boulder’s Laboratory for Atmospheric and Space Physics (LASP) will be there to present on a variety of topics—including on one of LASP’s specialties: CubeSats.
In May 2024, LASP—which built the first science CubeSat for NASA’s Science Mission Directorate—was also designated the first Center of Excellence for Capacity Building in CubeSat Technologies. Not only does LASP have a significant history in CubeSats, but also in astrophysics, with missions like Kepler, which launched in 2009 and discovered more than 2,600 planets outside our solar system, and the Imaging X-ray Polarimetry Explorer (IXPE) mission, which is making groundbreaking observations of cosmic events.
In recent years, astrophysicist Kevin France, a LASP researcher and associate professor in the Department of Astrophysical and Planetary Sciences at CU Boulder, and his team have been evolving the revolutionary use of CubeSats for astrophysics, which involves unique challenges given the great distances involved. This week, some of those challenges and achievements will be highlighted in a LASP-convened session at AAS, “From CubeSats to SmallSats—Big Science with Small Budgets in Astrophysics,” which will provide an overview of current SmallSat efforts in astrophysics and discuss future prospects, including unmet technological needs.
In the following Q&A, France explores how astrophysics—once considered to be the purview of big telescopes like Hubble—is being revolutionized by these small satellites.
How are SmallSats defined, and how do they differ from traditional space telescopes?
NASA defines SmallSats based on money. NASA has two SmallSat programs for astronomy. One is the Pioneers program, which is defined by its $20 million cost cap. The other is the CubeSat program, which is run through the astrophysics research and analysis program called APRA. Those are typically in the $5-10 million range. There’s no real size restriction on what we call a SmallSat other than the fact that size is proportional to cost. There’s usually a cost constraint there. If you’re talking about a traditional CubeSat, then you’re constrained by the launch vehicle. If your CubeSat deployer is only so big, you can only put a telescope of a certain size in it. So, from NASA’s perspective and from a practical perspective, it’s really cost and telescope size.
Why are SmallSats becoming more relevant in astrophysical research?
There’s been a big investment, but I believe only three astronomy CubeSats have flown. The results have been interesting. They’ve been able to do some niche science that hasn’t been achievable with larger facilities, but they haven’t all lived up to their initial science goals. So why are we doing it? Because we can. Technically, 15 years ago, there was no way to efficiently build a SmallSat because of the limitations of attitude control systems that would point to astronomical levels. Now we have that capability and other capabilities in the sector, like cheap launches. NASA is trying to provide a science opportunity that takes advantage of the technical advancements for SmallSat technology.
If science returns are still inconsistent, why keep investing in SmallSats?
We just haven’t been doing it long enough to know yet. The first astronomy CubeSats were only funded fewer than 10 years ago. It takes a couple of years to build and launch something, so only three of them have flown. The right time to ask that question is 2029. Because at that point, we’ll probably have about a dozen of them that have flown, and we’ll have a pretty good idea about what the science return is, what the success rate is. The other thing to consider is that these SmallSats are still doing science, and they’re still cost-comparable to things like sounding rockets and balloon payloads. They allow you to have long observing times or monitor things that happen over multi-month timescales that you can never do from a one-shot rocket or balloon. On the other hand, they’re small. The opportunities for technology development are a little bit different. It makes sense to have a balanced portfolio as long as they are demonstrated to be scientifically viable. We should come back and ask the question three years from now and see what the cost per science return looks like for these things.
What kind of astrophysics is being done with SmallSats at LASP?
At LASP, we have three astro SmallSats: the Colorado Ultraviolet Transit Experiment (CUTE), the Supernova remnants and Proxies for ReIonization Testbed Experiment (SPRITE), and the Monitoring Activity from Nearby sTars with uv Imaging and Spectroscopy (MANTIS) mission. CUTE was the first one. It launched in 2021. It’s studying a short-period transiting planet—so Jupiter-sized planets that are parked something like 0.02 or 0.03 astronomical units from their host star. So super close to their parent stars, super highly irradiated. They have all sorts of interesting atmospheric physics and chemistry that don’t happen in the solar system. CUTE is projected to last for another couple of months before re-entry. It was supposed to go for eight months, and it looks like it’s going to go for a little more than four years, which is great. SPRITE is set to launch in October this year. It will study ionizing radiation from galaxies and the drivers that cause a galaxy to evolve—the hot stars that produce a lot of ionizing radiation, the supernovae that, when they explode, blow big bubbles in the galaxy and drive, over a very long timescale, hundreds of millions of years, the evolution of galaxies. MANTIS will launch in 2027-2028 and is studying the host stars of exoplanets. It’s designed to provide the host star characterization for some of the planets that the James Webb Space Telescope is observing. It’s kind of like Webb’s stellar sidekick. It will also do a lot of fundamental stellar astrophysics, understanding the relationship between different parts of the star’s atmosphere, how stellar flares happen, and how they propagate through an atmosphere.
What kind of science results has CUTE returned?
Pretty good. We’ve done more science than we would have done in a sounding rocket payload at this point. CUTE has had a lot of technical challenges. It has met all of its original science goals, but it did not achieve our vision of everything it might have done. At the same time, the “e” in CUTE stands for “experiment” because it was only the second astrophysics CubeSat that was ever built. It was trying to make measurements of things that are challenging even for flagship facilities like the Hubble Space Telescope. We’re doing science that can’t be done in any other way except for with our flagship facilities, and I think that’s pretty exciting. Some of CUTE’s successes have been why NASA has continued to invest in this. But at the same time, you don’t want to make it sound rosier than it is. We’ve learned that doing full space missions on the very cheap is hard, and there are a lot of technical lessons that we’ve tried not to repeat on missions like SPRITE and MANTIS. But CUTE has done several peer-reviewed science papers, a number of peer-reviewed technical papers. We’ve also trained over 25 students on CUTE. I think by any measure, it’s been a great success.
At LASP, what role do SmallSats play in training students for missions?
The way we’ve developed the program for astronomy CubeSats at LASP has been very similar to what we’ve done for rockets for a very long time, and it’s similar to how NASA’s balloon program works. We bring students in to play all the roles on the mission—everything from the science lead, instrument development, systems engineer—and they get involved in all the different aspects of a real NASA mission from formulation up through launch and science. One of the great things about the program, which builds off of a long history in sounding rockets, is that it’s one of the only places where a student can come in and get the full mission experience. NASA does not have the risk tolerance to have students be engaged with hardware development on a $150 million mission. That’s not what those missions are there for. Because of that, our students who go through these programs tend to be very highly sought after. We often joke that they often have a greater than 100% success rate in job applications.
When assessing science goals, how do you choose to pursue a SmallSat mission over a more traditional option, like a sounding rocket or balloon mission?
It all depends on what the science requirements are. If there’s a high priority to go out and get a specific measurement that we only need to do once, then it might make more sense to do it in a rocket, because you can build a bigger telescope. You can build different types of instruments because you have a lot more volume. But for something like CUTE, it was studying transiting planets. Each planet transit takes about three hours. You can’t do that on a rocket where you get 10 minutes of observing time. Even on a long-duration balloon, you might get one of those because the balloon flight is only a couple of days. If you want to study phenomena that happen over a long time or you need to go back to them again and again, it really makes a good case for a SmallSat. It’s usually a specific science need which is not feasible to do with a large observatory. If we wanted to do CUTE with Hubble, we would need about 40% of Hubble’s annual observing cycle. And Hubble doesn’t give anybody 40% of its observing cycle. So, it’s science that’s out of reach for large facilities, but a good fit for smaller observatories.
How do SmallSats complement larger missions?
CUTE following up on Hubble’s discoveries is a good example. Hubble saw atmospheres escaping on giant planets. CUTE is helping build a large sample, which is impractical for Hubble to do. Looking forward, missions like the Habitable Worlds Observatory will rely on technology tested on SmallSats. We use these as technology development platforms, which is what we’ve done with rockets for a long time. If we want a new type of detector or optic, it’s expensive to develop alongside a flagship mission. But it’s relatively fast and cheap to test those on SmallSats. We’re flight-testing optical coatings, detector formats, gratings, all things that later go into larger missions.
Where is this technology headed in the next 5–10 years, and what is LASP doing to advance it?
At LASP, we’re flying these missions. We are the national leader in sounding rocket and SmallSat missions for UV astronomy. The designs for future instruments on major missions like Habitable Worlds are based on technology that we’ve built and flown at LASP—everything from mirror coatings to detectors to gratings. It’s all built on the foundation we’ve laid with SmallSats and suborbital projects. One thing I’d emphasize about LASP is that we do it all. If you have a science or instrument concept but are at an institution without the technical capability to build a spacecraft, we’re open to collaboration. We do a lot of in-house projects, but we also support groups across the country. It’s been hard for under-resourced institutions to get in the door, but we’re trying to change that. We’re very open to bringing new people into the field and collaborating with those who don’t have the infrastructure.
By Sara Pratt, LASP Senior Communications Specialist, with interview by Ravyn Cullor, LASP Marketing Specialist
Founded a decade before NASA, the Laboratory for Atmospheric and Space Physics at the University of Colorado Boulder is revolutionizing human understanding of the cosmos. LASP is deeply committed to inspiring and educating the next generation of space explorers. From the first exploratory rocket measurements of Earth’s upper atmosphere to trailblazing observations of every planet in the solar system, LASP continues to build on its remarkable history with a nearly $1 billion portfolio of new research and engineering programs.
