March 04, 2013, 1:42 PM — Astronauts on the International Space Station began unloading cargo from the SpaceX Dragon capsule on Monday, a day after the commercially delivered capsule was attached to the station.
Tom Marshburn, a space station astronaut and flight engineer, opened the hatch to the Dragon on Sunday, enabling Commander Kevin Ford of NASA and Canadian Space Agency Flight Engineer Chris Hadfield to enter the cargo craft.
Ford and Hadfield began unloading 1,268 pounds of Dragon's cargo early Monday. Over the course of the next few weeks, astronauts will then load 2,668 pounds of used items and experiments onto Dragon to be brought back to Earth on March 25.
The docking, originally scheduled for Saturday, was pushed back a day while NASA and SpaceX engineers repaired a problem with the Dragon's thruster system.
NASA and SpaceX launched the Dragon spacecraft atop a Falcon 9 rocket Friday morning from Cape Canaveral Air Force Station in Florida.
However, shortly after the 10:10 a.m Friday launch, a malfunctioning propellant valve brought down three of Dragon's four thrusters. It was late afternoon Friday before engineers got all of the thrusters, which enable the spacecraft's maneuvering and altitude control, working.
At 5:27 a.m. ET on Sunday, Dragon caught up with the station and moved to within 10 meters of it. Astronauts then used one of the station's robotic arms to grab the capsule, pull it in and attach it to the Earth-facing port of the Harmony module.
The capsule is scheduled to spend 22 days attached to the station.
This current mission is the second of 12 SpaceX flights contracted by NASA to resupply the space station. It also will be the third trip by a Dragon capsule to the orbiting laboratory.
After SpaceX made a demonstration flight in May 2012, it then launched the first official resupply mission last October, delivering 882 pounds of supplies.
Another successful commercial launch is an important milestone for NASA, which now depends on commercial flights since retiring the agency's fleet of space shuttles in the summer of 2011.
For the foreseeable future, NASA will need commercial missions to ferry supplies, and one day may send astronauts, to the space station, while the space agency focuses on developing robotics and big engines in preparation for missions to the moon, asteroids and Mars.