The carefully choreographed departure of the SpaceX Dragon re-supply vessel from the International Space Station got underway early Thursday as planned.
The demating of the first U. S. commercial spacecraft to reach the orbiting science lab at 4:07 a.m., EDT, followed by its Canadarm2 release, re-entry into the Earth's atmosphere and splashdown in the Pacific Ocean southwest of Los Angeles, Calif., should bring the nine day test mission to a close shortly shortly before 12 p.m., EDT.
Dragon, center top, awaits release from the grasp of the ISS Canadarm2 early Thursday. Photo Credit: NASA TV
A SpaceX recovery fleet -- including a 185 foot barge with crane, a smaller crew boat and a pair of inflatable boats with divers -- has gathered in the spashdown zone 560 miles southwest of Los Angeles. A pair of NASA P-3 Orion aircraft will fly overhead during the parachute descent to gather infrared data on the performance of Dragon's heatshield as well as serve as a communications relay.
Space station astronauts Don Pettit, Andre Kuipers and Joe Acaba gathered early in the day in the Cupola observation deck of the station at a control console for the 58-foot-long Canadarm2. Dragon was unberthed from the U.S. segment Harmony module using the robot arm.
"Dragon is unmated," Pettit informed Mission Control. Acaba took over the robot arm operations, hoisting Dragon out of its Harmony module berthing port.
Pettit is scheduled to release the freighter from Canadarm2's grasp 30 feet below the station at 5:35 a.m., EDT.
A succession of three propulsive maneuvers will push Dragon away, steering the vessel out of the NASA managed proximity operations zone. SpaceX will take control of Dragon for the first time since the capsule rendezvoused with the station for capture with Canadarm2 on on May 25.
Dragon's de-orbit burn is scheduled for 10:51 a.m., EDT. As the capsule descends, it will jettison a compartment called the "the trunk" used to stow external space station components. The trunk also provides the attach point for Dragon's stubby solar arrays.
A pair of drogue parachutes should deploy at 45,000 feet, followed by three main chutes at 10,000 feet. SpaceX divers will join Dragon as the capsule splashes down.
Once Dragon has been hoisted aboard the SpaceX barge, the recovery teams will set sail for the Port of Los Angeles in Long Beach -- a two to three day voyage. Once in port, Dragon will be transferred to an aircraft and flown to Central Texas, where SpaceX operates a test facility in MacGregor, near Waco, for the primary offloading of return cargo.
Dragon, which was launched with just over 1,000 pounds of nonessential food, clothing, crew equipment and research gear, is returning to Earth with nearly 1,400 pounds of crew equipment, scientific materials, space station hardware and space suit gear.
Some of the returning gear will be refurbished and re-launched to the six person space station.