SpaceX is making another supply run to the International Space Station for NASA. But it's the rocket's return — not its takeoff — that has space fans talking.
Minutes after Tuesday morning's planned launch from Cape Canaveral, the first stage of the unmanned Falcon rocket will aim for a vertical test landing on a barge in the Atlantic. The California company has attempted such landings on the open sea, but never on a platform like this.
SpaceX chief Elon Musk predicts a 50-50 chance of success at best. He says flying back boosters would allow them to be reused and save money.
NASA's previous delivery attempt by Orbital Sciences ended in a launch explosion in October. Researchers who lost experiments in the accident hustled to get replacements on this flight.