The SpaceX Falcon9/Dragon spacecraft lifted off early Tuesday, initiating the first U. S. commercial re-supply mission to the International Space Station.
SpaceX Dragon lifts off. Photo Credit: NASA TV
The Falcon 9 rose from Launch Complex 40 at Cape Canaveral Air Force Station, Fla., at 3:44 a.m., EST, thundering away on a northerly arc through a darkened sky. The Dragon separated from the two-stage launcher on schedule, and a successful solar array deployment followed at 11 minutes, 19 seconds into flight. The ISS orbited 250 miles over the North Atlantic Ocean east of Newfoundland as the Falcon 9 departed.
A trouble-free countdown and departure initiated a planned nine-day mission that promises to bring the unpiloted Dragon within 1.5 miles of the six person space station early Thursday for a critical series of navigation and communications checks. If all goes well, the Dragon will retreat to a point about 125 miles above and behind the station, returning early Friday for more systems tests before moving within range of the orbiting laboratory’s Canadarm 2.
Station astronauts Don Pettit, of NASA, and Andre Kuipers, of the European Space Agency, will be posted at a control console in the station’s cupola observation deck ready to grapple the freighter and berth it to the U. S. segment Harmony module shortly after 11 a.m., EDT.
Dragon, flying under the banner of NASA’s Commercial Orbital Transportation Services program, is scheduled to remain docked until May 31. The length of the stay, once intended to be twice as long, is constrained by an increasing solar beta angle, which exposes the orbital plane of the space station to more heat from the sun.
Efforts to begin the mission on Saturday were aborted a half second before lift off, when the Falcon 9 flight control system detected a slight overpressure in the No. 5 Merlin first stage engine. Engineers identified a faulty nitrogen check value in the first stage power plant. The faulty valve, which was allowing unwanted nitrogen to flow into a liquid oxygen fill line, was replaced.
A post-shutdown analysis indicates the May 19 launch could have proceeded safely, according to SpaceX president Gwynne Shotwell. But she added, “The computer software did what it was supposed to, which is good.”
The first stage is powered by nine SpaceX-developed Merlin liquid oxygen/kerosene engines, the second stage by one of the power plants.
Dragon is carrying about 1,014 pounds of non-critical cargo, including food, computer equipment and student experiments within a Nanoracks Module. If the linkup is successful, the capsule will depart the station with about 1,400 pounds of experiment samples, spacesuit gear and hardware slated for refurbishment.
Once undocked, Dragon will re-enter the Earth’s atmosphere, descending under parachute into the Pacific Ocean several hundred miles off the southern California coast.
SpaceX plans to recover the re-usable Dragon capsule.