Cargo Unloaded, Space Station Crew Preps Dragon for Return Trip

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WASHINGTON — More than a metric ton of cargo, mostly NASA science experiments, was brought aboard the international space station (ISS) March 5-6 from Space Exploration Technologies Corp.’s (SpaceX) Dragon spacecraft, which crew members are now packing with cargo scheduled to return to Earth March 25.

Besides the nearly 700 kilograms of cargo in Dragon’s pressurized interior, which astronauts brought aboard ISS March 5, the capsule also carried to ISS a pair of grapple bars and support equipment, weighing nearly 40 kilograms, in its unpressurized exterior trunk compartment. The bars were unloaded March 6 using the space station’s robotic arm, Canadarm2. This mission, SpaceX’s second under a 12-flight, $1.6 billion Commercial Resupply Services contract signed in 2008, was the first to carry unpressurized cargo in Dragon’s trunk.

Dragon got to the space station a day later than NASA and SpaceX planned. After reaching orbit March 1 aboard its Falcon 9 carrier rocket, three of the capsule’s four thruster pods failed to activate as expected, delaying solar-array deployment and all but eliminating Dragon’s maneuverability. SpaceX brought all four thruster pods back online within hours, but still missed its scheduled March 2 rendezvous with ISS.

NASA spokesman Josh Byerly said in a March 6 email that agency and SpaceX personnel will meet on or around March 21 to make sure that Dragon’s systems are in good shape for its planned return to Earth March 25.

All that Junk in Dragon’s Trunk?

Meanwhile, the first week of berthed operations at ISS marked a milestone for NASA and SpaceX, as Canadarm2 was used for the first time to remove cargo from Dragon’s exterior trunk. Canadarm2 unloaded a pair of grapple bars — known officially as Heat Rejection Subsystem Grapple Fixtures — which now will be stored on the station’s Mobile Base System, a mobile platform that can be moved across the length of the space station along a rail.

“These are grapple bars that would help the crew remove a failed radiator, should that ever become necessary,” Byerly wrote in an email. The hardware will be installed during a summer spacewalk, he added.

Dragon is scheduled to splash down March 25 somewhere off the coast of Baja California, Mexico, loaded with 1,200 kilograms of cargo. Only the capsule returns to Earth. Dragon’s expendable trunk is jettisoned prior to re-entry.

The Commercial Resupply Services program is NASA’s way of getting cargo to and from ISS using privately operated spacecraft to replace some of the capacity once offered by the U.S. space shuttle fleet, which was retired in July 2011. SpaceX now operates the only spacecraft that can bring significant amounts of cargo back to Earth. NASA’s other commercial cargo carrier, Orbital Sciences Corp. of Dulles, Va., will offer only cargo delivery and waste disposal with its expendable Cygnus space freighter.

Cygnus has yet to fly in space. Orbital will launch the vehicle from Wallops Island, Va., using the Antares rocket it is developing with financial help from NASA. A demonstration delivery mission is scheduled for later this year, pending a successful Antares test launch in early April. Orbital’s eight-flight delivery contract is worth $1.9 billion.

Dragon was berthed March 3 to ISS’s Earth-facing Harmony node using Canadarm2. For the berthing, as with the unloading of the grapple bars, the Canadian-built robotic arm was operated by ground controllers at the Johnson Space Center in Houston. Dragon’s hatch was opened for cargo unloading immediately after berthing, a day earlier than scheduled.

All that Junk in Dragon’s Trunk?

Meanwhile, the first week of berthed operations at ISS marked a milestone for NASA and SpaceX, as Canadarm2 was used for the first time to remove cargo from Dragon’s exterior trunk. Canadarm2 unloaded a pair of grapple bars — known officially as Heat Rejection Subsystem Grapple Fixtures — which now will be stored on the station’s Mobile Base System, a mobile platform that can be moved across the length of the space station along a rail.

“These are grapple bars that would help the crew remove a failed radiator, should that ever become necessary,” Byerly wrote in an email. The hardware will be installed during a summer spacewalk, he added.

Dragon is scheduled to splashdown somewhere off the coast of Baja California, Mexico, on March 25, loaded with 1,200 kilograms of cargo. Only the capsule returns to Earth. Dragon’s expendable trunk is jettisoned prior to re-entry.

The Commercial Resupply Services program is NASA’s way of getting cargo to and from ISS using privately operated spacecraft to replace some of the capacity once offered by the U.S. space shuttle fleet, which was retired in July 2011. SpaceX now operates the only spacecraft that can bring significant amounts of cargo back to Earth. NASA’s other commercial cargo carrier, Orbital Sciences Corp. of Dulles, Va., will offer only cargo delivery and waste disposal with its expendable Cygnus space freighter.

Cygnus has yet to fly in space. Orbital will launch the vehicle from Wallops Island, Va., using the Antares rocket it is developing with financial help from NASA. A demonstration delivery mission is scheduled for later this year, pending a successful Antares test launch in early April. Orbital’s eight-flight delivery contract is worth $1.9 billion.

Dragon was berthed to ISS’s Earth-facing Harmony node using Candarm2 on March 3. For the berthing, as with the unloading of the grapple bars, the Canadian-built robotic arm was operated by ground controllers at the Johnson Space Center in Houston. Dragon’s hatch was opened for cargo unloading immediately berthing, a day earlier than scheduled.

 

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