SpaceX Dragon, unmanned cargo spacecraft, returned yesterday from LEO orbit where it has spent over one month docked to Earth facing Harmony module of International Space Station.
It was end of the CRS-9 mission, which covered among others delivering to ISS 2257 kg of supplies, including weighing almost half ton International Docking Adapter. After extracting IDA from unpressurized cargo section of Dragon last week, spacecraft was ready to be filled with scientific experiments and samples (transferred manually by crew members into pressurized section) and trash (which were loaded into unpressurized section of the Dragon). During last week, ISS crew members loaded Dragon with 580 kg of scientific material including blood and urine samples and twelve live mice from experiment sponsored by JAXA. Total pressurized cargo delivered to Earth was planned for 1450 kg. In spite of samples rest was of the cargo were EVA space suits and trash. Landing of the Dragon was planned on Pacific Ocean, 524 km from Baja, California at 15:47 GMT.
Undocking was performed according to plan, at 10:10 GMT. Hatch of the Dragon was closed already on Thursday, day before undocking. NASA decided to designate for controlling whole procedure and giving final "release" command astronaut Kate Rubins (NASA) and astronaut Takuya Onishi (JAXA). Both were prepared already in early morning hours on Friday, August 26 and wait inside Cupola module at control panel. Canadarm2 robotic arm, controlled by specialists from Houston NASA Control Center (along with specialists at SpaceX Mission Control Center -MCC-X-in Hawthorne, California), carefully grabbed docked Dragon. It was ready for final command which should be given by Rubins and Onishi. Two minutes before planned undocking, at 10:08 GMT Control Center decided to go final "go" for undocking. After three minutes, at 10:11 GMT, when ISS flew over Timor Sea, Dragon finally was released and started its autonomous flight to Earth still being monitored by Kate Rubins and Takuya Onishi until it passed distance 200 m from ISS. This moment was preceded by three engine burns: first at 10:16 GMT, second at 10:17 GMT and last, third one, which put Dragon for 200 m from Station, conducted at 10:24 GMT.
Five hours later, at 15:09 GMT Dragon controlled by MCC-X fired its Draco thrusters to change orbit and start to perform reentry maneuver. During ten minutes of burn, over Indian Ocean at 15:13, Dragon jettisoned its unpressurized trunk. After burn was finished, communication with spacecraft was halted due the passing through dense upper layers of atmosphere. At 15:39 GMT Dragon deployed two drag parachutes and few minutes later three main parachutes with diameter at 35 m each, were extracted and opened on altitude of 3000 m. At 15:48 GMT Dragon gently touched waters of Pacific with speed of 17 km/h. Dragon was recovered by SpaceX team with special ship and is still on its way to cargo port near Los Angeles, where cargo will be extracted and send to NASA laboratories. Next it will be delivered to SpaceX’s test facility in McGregor, Texas, for tests and processing; whole vehicle will be also carefully cleaned from small residues from toxic fuel from thrusters.