NASA astronaut Don Pettit, left, and European Space Agency astronaut Andre Kuipers train to capture Dragon with the station's robot arm. Photo Credit: NASAThe SpaceX Dragon began the final leg of the first U.S. commercial re-supply journey to the International Space Station early Friday.
If all goes well, the unpiloted capsule should maneuver to a point below the six person orbiting science lab and within reach of the station’s 58-foot-long Canadarm2 just before 8 a.m., EDT.
Station astronauts Don Pettit and Andre Kuipers, of NASA and the European Space Agency, will be gathered at the control console in the cupola observation deck prepared to grapple the capsule with the robot arm and hoist it to a berthing point on the U.S. segment Harmony module just after 12 p.m. NASA astronaut Joe Acaba is assisting.
Launched from Cape Canaveral Air Force Station atop a SpaceX Falcon 9 rocket early Tuesday, Dragon sailed within 1.5 miles of the station on Thursday, testing the navigation and communications systems required for Friday’s track and capture operations.
Dragon then departed the station in a looping race track trajectory that took it well out in front, above and then back and behind the station.
Late Thursday, the NASA-led space station mission management team granted the agency’s flight controllers in Houston and those at the SpaceX headquarters in Hawthorne, Calif, formal permission for Dragon’s return.
A series of propulsion maneuvers that commenced at 3 a.m., EDT, began to steer Dragon toward a point 250 meters below the station.
There, Dragon will slow, and await a series of commands from Hawthorne and the station astronauts. These will close the separation to 220 meters and re-open the distance to 250 meters to test the pause, retreat and abort capabilities of the spacecraft.
Following a series of “Go/No Go” deliberations between NASA’s Mission Control in Houston and the SpaceX control team in Hawthorne, Dragon will advance to a “capture” point at 10 meters below the station for the capture.
The astronauts plan to open Dragon early Saturday to unload just over 1,000 pounds of food, clothing, research equipment, empty cargo containers and computer equipment.
Dragon will be re-loaded with nearly 1,400 pounds of crew equipment, station hardware, space suit gear and experiment samples for return to Earth.
Currently, Dragon is scheduled to unberth with the help of Canadarm2 and the astronauts on May 31. The capsule will re-enter the Earth’s atmosphere and aim for a splashdown under parachute in the Pacific Ocean off the coast of southern California about mid-day.
The Dragon mission marks a key milestone in NASA’s Commercial Orbital Transportation Services program, a six-year-old initiative to hand over the cargo and crew launch capabilities long shouldered by the space shuttle flieet to the private sector.
NASA’s second COTS partner, Orbital Sciences Corp., plans a similar test mission later this year.