Refueling in space could extend satellites’ lives and spacecrafts’ travels

Just as with a car, regular maintenance will extend a satellite’s lifetime and ensure that a problem like running out of fuel doesn’t cut its usefulness short. But reaching a satellite to deliver much-needed services can be difficult and expensive when a satellite is orbiting the Earth.

NASA is testing a few tools that would make it much easier to repair and refuel satellites — even those that were never designed to receive maintenance.  The agency just successfully tested a robotic arm refueling system on the ground and is now gearing up to bring it to the International Space Station for further tests.

“With more than 400 satellites in space that could benefit from robotic servicing, we thought a refueling test was the best place to start,” NASA Satellite Servicing Capabilities Office associate director Frank Cepollina said in a NASA post. “We wanted to demonstrate technologies that build life-extension capabilities — and jumpstart a discussion about new ways to manage assets in space.”

NASA tests its robotic refueling arm on Earth. Photo courtesy of NASA.
NASA tests its robotic refueling arm on Earth. Photo courtesy of NASA.

NASA names extended human exploration as one inspiration for the project. If we refuel spacecraft once they’ve left Earth, it could help them travel farther than they’ve ever traveled before. Like the satellites, their use wouldn’t be limited by how much fuel they can pack into their hull.

MIT expanded on that idea this week with a proposal to store extra rocket fuel in space. Researchers there focus on spacecraft traveling between the Earth and moon, where they could meet up with a refueling “depot” to pick up an extra tank of fuel. Ships heading back to Earth could drop off any extra tanks for future ones to pick up. The tanks would be transferred by a robot or astronaut.

That kind of flexibility could help lunar exploration missions visit more remote parts of the moon, which earlier lunar missions passed up due to the larger amount of fuel that would have been needed.

Daisy-chaining fuel depots even farther into space could allow missions to venture much farther than they do today and ease travel to planned destinations like Mars.

“Whatever rockets you use, you’d like to take full advantage of your lifting capacity,” MIT Department of Aeronautics and Astronautics professor Jeffrey Hoffman said in the release. “Most of what we launch from the Earth is propellant. So whatever you can save, there’s that much more payload you can take with you.”