The International Space Station's mission management team has cleared the SpaceX CRS-2 Dragon resupply capsule for a rendezvous and berthing with the six-man orbiting science laboratory early Sunday, following the post-launch recovery of three thruster pods and successful orbit raising maneuvers.
SpaceX Dragon capsule prior to Canadian robot arm grapple in Oct. 2012. Photo Credit: NASA TV
Station commander Kevin Ford and flight engineer Tom Marshburn will position themselves at a control panel for the Canadian robot arm in the station's Cupola observation deck for a scheduled grapple at 6:01 a.m., EST.
A series of joint NASA and SpaceX control team "go/no go" decisions will be required for the unpiloted Dragon to ease within reach of the 58-foot long robot arm. Once captured, Dragon and its cargo will be guided to a berthing on the station's U.S. segment Harmony module by NASA's Mission Control team.
The supply craft will remain berthed until March 25, as originally planned, even though the capsule's arrival was postponed a day by the thruster issue.
The SpaceX Falcon9/Dragon lifted off from Cape Canaveral Air Force Station, Fla., on Friday at 10:10 a.m., EST. The company reported a trouble free climb to orbit, but an obstruction or stuck valve in the helium pressurization plumbing prevented three of four thruster banks on the capsule from activating. In all, 18 thrusters raise the capsule's altitude and provide attitude control.
The SpaceX control team recovered all of the thruster banks and began a series of delayed rendezvous maneuvers Friday afternoon and evening.
"SpaceX said it has high confidence there will be no repeat of the thruster problem during rendezvous, including its capability to perform an abort, should that be required," NASA said in an update that followed a meeting Saturday in which the multi-national ISS management team reviewed the company's recovery actions.
Early Saturday, ISS astronaut Chris Hadfield, of Canada, offered an update as well.
"The Dragon resupply ship is 7 kilometers above the ISS and 2,850 kilometers in front, her problems fixed," said Hadfield by Twitter. "Replanning the rendezvous and grapple schedule."
SpaceX is delivering a 2,700 pound cargo, including the mass of protective packaging, the company reports. The deliveries include U.S., European and Japanese research gear as well as a pair of "grapple bars" that will be placed outside the station so that they can be fitted to radiator panels during a future spacewalk.
The station flight is the second flown by the Hawthorne, Calif.-based launch company founded by Elon Musk under a $1.6 billion supply services NASA contract awarded in late 2008. The first Dragon shipment arrived in October. Dragon carried out a demonstration mission to the ISS under the auspices of NASA's Commercial Orbital Transportation Services program last May.While Dragon is berthed, it will be re-loaded with just over 3,000 pounds of equipment, including protective packaging for return to Earth. Much of it will be experiment samples and equipment in need of refurbishment.