Silhouetted against fluffy white clouds on the Earth’s surface, the Roll-Out Solar Array on the International Space Station unfurled in space for the first time and it looks like the frog of a giant space frog.

The Roll-Out Solar Array — called ROSA for short — is a new kind of solar panel that is 20 percent lighter and more than four times more compact than traditional panels. And crucially, it is able to roll into coil when it isn’t active.

This week, NASA released the video of its first deployment, showing the panels slowly unroll to catch the sun. The panels are being tested to see how their action could affect a satellite in flight. It’s possible that the design could be used to bring solar power to remote areas of Earth, reduce the cost of powering satellites, and could help us power spacecraft to a Mars or deep-space mission.


These new type of solar panels insert crystalline solar cells only a few millimeters thick into a flexible material that allows the array to roll and unroll. The material is coiled around itself and is unrolled by supports on both sides that uncoil alongside the solar sheet until they are fully unraveled. This mutual unrolling makes the array look like a party horn that unrolls when888 you blow into it, or a frogs tongue shooting out in slow motion.

While the array is in use, its thin membranes can start to vibrate when the satellite moves, or when it goes from shade to light and suddenly heats up.

“This structure is very thin, only a few millimeters thick, and heats up very quickly, dozens of degrees in a few seconds,” says Jeremy Banik, lead researcher and engineer at the Air Force Research Laboratory in New Mexico. “That creates loads in the wing that could cause it to shudder. That would create problems, for example, if a satellite was trying to take a picture at the same time.”

The video was taken to help researchers compare how the array works in space with the predictions the team has made based on experiments on Earth.

Its compact size makes this type of solar panel valuable for powering satellites and deep-space or Mars missions because it is a lot cheaper to launch than traditional solar panels. In its plan for sending humans to Mars released back in September 2016, SpaceX imagined solar arrays fanning out from a spacecraft like so:

NASA’s current-day unrolling solar panels might also be used for spacecraft that need energy for deep-space travel. Here’s a full NASA video of how the ROSA experiment went down:

Photos via NASA Johnson