[Interview+] Two Football Fields of Solar Sail in One Rocket | NIAC 2026

Fraser Cain (0:00)

The current propulsion systems are chemical rockets and ion engines, with the occasional dabbling into solar sails. But the problem with solar sails is that they are incredibly fragile. When you look at some of the really big solar sails that have been built, you have this boom, and you have to stretch out this really, really flimsy mylar fabric that can tear. And if you're going to test it on earth gravity, then you're going to have to find a gigantic room, and the gravity is going to be pulling this thing down, and it's a nightmare to test beyond a certain point, complicated to deploy. And in fact, many of the solar sails that have been launched into space have had problems with the deployment of their booms and their solar sails. So is there an easier way? Now my guest today is Dr. Artur Davoyan, and he is an associate professor of mechanical and aerospace engineering at UCLA. And he and his team have been the recent recipient of a phase one NIAC grant. In this case, the research is called Coilable Stacked Solar Sails for Very High Delta V Emission. But the gist is that it's a stack of cards that are attached, and they turn into this giant, long, rectangular solar sail as they are deployed. And so you don't have to be deploying a boom in two directions, really just one dimension. And there's all kinds of advantages that this can give you. Theoretically, I mean, Artur and his team have got the phase one NIAC grant, so this is what they're going to try and figure out. So solar sails, advanced propulsion systems, if that's what you're into, check out this interview. Artur, first, congratulations on winning a NIAC phase one award. And this is great because this fits deeply into my sort of some of my favorite kinds of technology, solar sails, alternative propulsion systems.

Tell us about your project.

Artur Davoyan (1:48)

Thank you, Fraser. Thanks for finding time.

So, we are interested in solar sails in general, and solar sails are this very large area spacecraft, ultra-lightweight, large area spacecraft, CNS-L membranes. And they use solar radiation pressure for propulsion. So, the light hits the membrane, gets reflected, and that's where you get the small force that pushes the spacecraft.

Now, the beauty of that is because you don't use any propellant, so you don't exhaust the fuel, and therefore, you can propel sort of indefinitely, and by doing that, you can get the accelerations and velocities that are much, much faster than what you can get with conventional propulsion systems like rockets, for example, you know, chemical rockets or ion engines. And because of that, you can get to trajectories, to orbits, to destinations that are not possible with current spacecraft. Like, for example, there's no way you can get to the polar regions of the sun. Like, if you want to get there and explore the sun and the polar regions, there is no way you can get there. So, solar cells can't do that. Now, the challenge with the solar cells, there are many challenges. You have to have very large area spacecraft. The larger it is, the better it is. Larger area means that you collect more sunlight. And the smaller is the mass of the spacecraft, that means the force is Newton's law, F equal to ma, right? So, mass times acceleration. So, you want to have very large acceleration. So, the force is, the thrust is something that you collect, which is larger area to collect more sunlight, you reflect more sunlight, you get more force. But you also want to minimize the mass. So, you want to have thin film, very lightweight structure that is extremely large, like 10,000 meter square, for example, which is 100 meters by 100 meter type of spacecraft.

Now, there are challenges with that, of course. How do you build a thin film membrane that large? How do you deploy it in space? How do you control this entire thing, the spacecraft, so that it's very small perturbations on different edges of the spacecraft that can just topple it, but doesn't become stable? So all of these challenges exist. People have been trying to solve that. They have had some technology demonstration missions. They have been some science missions with the use of spacecraft. They're usually smaller. And every now and then you see that there are certain challenges that, certain theme of challenges that persists.

They are being resolved, but they still persist. Like one of them is, for example, deploying the spacecraft. So usually you stow the sail in a small package, and then you deploy with the booms and all of that. So we thought, deploying a large area sail, like 100 meters by 100 meters is very difficult. So we thought of the structure architecture that can remove the challenges of the deployment, make it simpler. So that's where we came up with this idea for this particular NIAC program, where we have like the sails that are unfurled. So we don't really stow the sails themselves. So there's a stack of sails, but what we deploy is basically, we just kind of like a ladder, we push them apart from each other. Of course, we have booms and all of that, but we sort of simplify the deployment, a little bit simplify the deployment as compared to conventional square sails. So by doing that, we hope to get simpler deployment mechanism and deploy larger sails and therefore get the performance that we want.