A private space plane is slated to fly on its own for the first time in the next six to eight weeks, a key drop-test milestone in the vehicle's quest to fly astronauts on roundtrip space missions.

The Dream Chaser spacecraft, built by aerospace firm Sierra Nevada Corp., will be released by a carrier helicopter at an altitude of 12,000 feet (3,657 meters) or so, then fly back and land autonomously on a runway at NASA's Dryden Flight Research Center in California.