Watch the Falcon 9 launch from pad 39A

A spaceship designed to ferry astronauts into orbit by 2017 is set for a major test Wednesday, when SpaceX plans to blast the capsule away from Cape Canaveral on a mile-high demo flight to simulate the craft’s ability to protect occupants in the event of a catastrophic rocket mishap on the pad.

SpaceX test-fired a Falcon 9 rocket for the second time Saturday after replacing a valve following an earlier static fire test Wednesday. The move has postponed the Falcon 9 rocket’s launch with the Amos 17 commercial communications satellite to no earlier than Tuesday.

A Russian Progress freighter carrying nearly three tons of fuel, cargo and supplies for the International Space Station took off from Kazakhstan Saturday, two days after an uncommon last-minute abort for its Soyuz booster.