In the four days following its launch, the Dragon cargo carrier spacecraft followed a complex set of maneuvers, and was allowed to dock at the International Space Station May 25.
“Today marks another critical step in the future of American spaceflight,” NASA Administrator Charles Bolden said. “Now that a U.S. company has proven its ability to resupply the space station, it opens a new frontier for commercial opportunities in space – and new job creation opportunities right here in the U.S. By handing off space station transportation to the private sector, NASA is freed up to carry out the really hard work of sending astronauts farther into the solar system than ever before. The Obama Administration has set us on an ambitious path forward and the NASA and SpaceX teams are proving they are up to the task.”
The next day, May 26, the hatches between Dragon and the ISS Harmony module were opened, and the unload operation for the historic first ever cargo carried to the ISS by a commercial firm was started.
Dragon, built, launched and controlled by SpaceX has thus far performed perfectly. Return cargo is being placed on board at press time, and the hatches are scheduled to be closed May 30. On May 31, the Expedition 31 crew members will detach Dragon from Harmony; maneuver it to a 33-foot release point and un-grapple the capsule. Dragon will de-orbit approximately four hours after leaving the station, taking about 30 minutes to re-enter Earth’s atmosphere and landing in the Pacific Ocean about 250 miles west of Southern California.
After launch, the Dragon spacecraft performed these scheduled steps. Its solar arrays were deployed, to provide power to the craft. The covering doors of the proximity sensors were opened.
The Absolute GPS system was checked and found to be working well. Pulsed and full abort operations were also demonstrated. The free drift condition was then demonstrated. Free drift is the capsule status when it is grappled by the ISS. Proximity operations sensors were then checked. All these steps were monitored by NASA which gave permission for the docking when they were all successfully completed.
After its trajectory brought it within range, Dragon’s thrusters fired, bringing the vehicle to 2.4 kilometers below the space station. The vehicle completed two key tests at that distance. Dragon demonstrated its Relative GPS and established a communications link with the ISS. The COTS UHF Communication Unit was activated. The ISS portion of CUCU had been placed onboard during one of the last shuttle missions to ISS. The communication link was verified having the station astronauts turn on the Dragon strobe light.
Following these tests, the Dragon capsule was cleared by NASA to approach the station May 25. Dragon then performed a series of intricate test maneuvers as it approached the orbiting laboratory. These maneuvers were required to demonstrate the maneuvering and abort capability of Dragon prior to approaching and moving into a 65-foot “berthing box” where it was grappled by NASA astronaut Don Pettit using the station’s robotic arm at 9:56 a.m., EDT.
European Space Agency astronaut Andre Kuipers installed the capsule on the bottom of the station’s Harmony node at 11:52 a.m.
NASA astronaut Joe Acaba completed berthing operations by bolting the Dragon to Harmony at 12:02 p.m.
May 26, at 5:53 a.m., astronauts opened the hatches. Pettit opened the hatch and he and Russian cosmonaut Oleg Kononenko, station commander, entered the Dragon for initial inspections. They were joined at the entrance of the hatch by Kuipers and Russian cosmonaut Gennady Padalka. The operation went smoothly and was ahead of schedule. Dragon’s interior looked good and Pettit remarked on the vehicle’s new car smell.
“Congratulations to the SpaceX and NASA teams,” said William Gerstenmaier, associate administrator for NASA’s Human Exploration and Operations Mission Directorate at the agency’s headquarters in Washington. “There is no limit to what can be accomplished with hard work and preparation. This activity will help the space station reach its full research potential and open up space-based research to a larger group of researchers. There is still critical work left in this test flight. Dragon-attached operations and cargo return are challenging and yet to be accomplished.”
The Dragon capsule delivered 1,014 pounds of supplies to the station, which included non-critical experiments, food, clothing and technology items. After off loading the cargo, Dragon was then loaded with 1,367 pounds of hardware and cargo no longer needed aboard the station in preparation for the spacecraft’s return to Earth. Dragon and station hatches are scheduled to be closed May 30.
May 31, the Expedition 31 crew members will detach Dragon from Harmony; maneuver it to a 33-foot release point and un-grapple the capsule. Dragon will de-orbit approximately four hours after leaving the station. It will take about 30 minutes to re-enter Earth’s atmosphere and land in the Pacific Ocean about 250 miles west of southern California. SpaceX has a recovery ship stationed in the landing area.
“The investments made by the United States to stimulate the commercial space industry are paying off,” said Philip McAlister, director for Commercial Spaceflight Development at NASA Headquarters. “SpaceX achieved what until now was only possible by a few governments, and the company did it with relatively modest funding from the government.”