Astronauts at the Space Station received the go-ahead to capture SpaceX's Dragon with the ISS' robotic arm just before 10 a.m. EDT, while the ISS was orbiting 251 miles above Australia. Once the craft is securely attached to the ISS, the astronauts will proceed to open its hatch, which should occur around 5 a.m. on Saturday. The complicated procedure is estimated to take two hours. After spending 18 days attached to the ISS, Dragon will return to Earth, splashing down in the Pacific Ocean.
Falcon 9, the rocket carrying Dragon, took off from Cape Canaveral, Fla., on May 22 at 3:44 a.m. EST. A planned May 7 launch date, already pushed back from dates in February and April, resulted in nothing more than a “static fire test” of the rocket engines on the launch pad. On May 19, launch officials found an engine glitch seconds before liftoff. According to NASA, it will return carrying 620 kilograms of freight.
Earlier in the week, the unmanned capsule completed a series of maneuvers in preparation to dock with the space station. According to a press release issued by SpaceX on Thursday, “Early this morning, Dragon’s thrusters fired, bringing the vehicle 2.4 kilometers below the International Space Station. The vehicle completed two key tests at that distance. Dragon demonstrated its Relative GPS and established a communications link with the International Space Station using CUCU. Astronauts commanded on Dragon’s strobe light to confirm the link worked.”
These tests were important steps toward proving that Dragon has the ability to be controlled by astronauts inside the ISS and will be able to successfully dock with the large craft.
The U.S. government decided several years back that low-Earth orbit tasks, such as replenishing the ISS, should be doled out to contractors. This meant the Space Shuttle program, with its increasingly high maintenance costs, could be retired. When the Atlantis returned to Earth for the last time in July 2011, the 30-year shuttle program came to an end, briefly leaving other nationalities in charge of resupplying the station.
The ISS, essentially a $100 billion research lab co-owned and operated by the U.S., Canada, Russia, Japan and Europe, is the biggest piece of hardware in space, weighing 360 tonnes. Orbiting about 390 kilometers above the Earth, it can accommodate six crew members; many scientific experiments take place on board in zero gravity.
NASA awarded contracts worth a combined $3.6 billion back in 2008 to SpaceX and Orbital Sciences Corp., of Dulles, Va., under its Commercial Resupply Services program. The firms were contracted to haul 20 tonnes of cargo to the Space Station through 2016. SpaceX will make 12 flights with its Falcon 9 and Dragon spacecraft, while Orbital’s Antares and Cygnus spacecraft will undertake eight flights.