Researchers at the Kennedy Space Center in Florida will try out a rotor system that could be used in place of parachutes on returning spacecraft, NASA said.

The design would give a capsule the stability and control of a helicopter, although the rotors would not be powered, the space agency reported.

Instead, wind passing over the rotors as the capsule descends would make the blades turn, a process called auto-rotation that has been practiced repeatedly on helicopters making emergency landings but never tried on spacecraft.

Researchers said they were starting with scale models of rotor-equipped spacecraft to gather initial results.

"The purpose of the testing we're doing here is to study how to get the rotor starting to spin," said Jeff Hagen, an engineer from the Johnson Space Center in Houston. "We're trying to build as much of that story as we can."

The goal is to give real spacecraft a soft landing with enough control that they could touch down anywhere in the world like a helicopter, whether on a runway or the top of a building, researchers said.

"You can land gently and you can land where you want, you don't have to land out in the ocean," Jim Meehan, an engineer at the Marshall Space Flight Center in Huntsville, Ala., said. "Compared to a parachute, you get a soft landing and you get a targeted landing."