With one successful test flight of a private space capsule under its belt, a commercial spaceflight company is looking ahead to another big step: upgrading its robotic Dragon spaceship to carry astronaut crews.

The Hawthorne, Calif.-based Space Exploration Technologies – known as SpaceX – has submitted a proposal to NASA's Commercial Crew Development (CCDev) program to begin developing a version of its Dragon spacecraft to transport people into orbit.

The company submitted the proposal Dec. 13, just five days after launching the first Dragon space capsule into orbit, returning it to an ocean splashdown, and fishing the craft out of the Pacific Ocean.