Future satellites could breathe air to stay spaceborne

When a satellite reaches orbit, it still has to contend with Earth’s atmosphere. Even 200 miles (320 kilometers) above the Earth’s surface, stray air molecules abound. They slow a satellite down, stealing its momentum, and dragging it inexorably downward, to its doom.

But a technology currently under study could turn those stray air molecules into a source of fuel to keep satellites aloft. The concept, called air-scooping electric propulsion (ASEP), has been discussed in space circles for decades, but is now getting renewed attention. And it could be a potential game-changer for satellite operators, argues a paper issued last month by researchers at The Aerospace Corporation, a nonprofit corporation based in El Segundo, California.