- The SpaceX Dragon was successfully "tamed," the ISS commander says
- The capsule will spend about 18 days at the ISS and bring back scientific experiments
- One of the capsule's 9 engines died during launch Monday
The SpaceX Dragon was successfully berthed at the International Space Station on Wednesday as the station's crew caught and secured the unmanned cargo capsule high above Earth, NASA announced.
Japanese astronaut Akihiko Hoshide latched onto Dragon with a robotic arm at 6:56 a.m. ET. By 9:03, the craft was attached to the station's docking module, the space agency said.
"Looks like we've tamed the Dragon," NASA's Sunita Williams, commander of the current ISS mission, said in a statement released by SpaceX.
The Dragon mission lifted off Sunday carrying about a half ton of supplies for the station's crew. It caught up with the ISS Wednesday morning, 273 miles over the South Atlantic Ocean, NASA said.
"This is a big moment in the course of this mission and for commercial spaceflight," SpaceX founder Elon Musk said in a statement released by the company. "We are pleased that Dragon is now ready to deliver its cargo to the International Space Station."
It's one of a dozen missions ordered by NASA under a contract with the company. A Dragon capsule successfully delivered 1,000 pounds of cargo to the station in May.
NASA says the ISS crew will start unloading the craft on Thursday.
Dragon will be attached to the station for two and a half weeks. After the supplies are pulled off, astronauts will reload the craft with scientific experiments and failed equipment that can be repaired and sent back. It's scheduled to return to Earth on October 28.
The Dragon remained on course despite engine trouble on its booster after liftoff Sunday night. A minute and 19 seconds after the Falcon 9 rocket lifted off from Cape Canaveral, Florida, one of its nine Merlin engines "lost pressure suddenly," the company disclosed Monday.
The rocket "did exactly what it was designed to do," as its flight computer made adjustments to keep the Dragon headed into the proper orbit, the company said.
However, a communications satellite the Falcon 9 carried as a secondary payload did not end up in its designated orbit. In a statement issued Wednesday afternoon, SpaceX said it had to use more fuel and liquid oxygen to put the Dragon into orbit because of the failed engine.
"For the protection of the space station mission, NASA had required that a restart of the upper stage only occur if there was a very high probability (over 99%) of fully completing the second burn," SpaceX said. "While there was sufficient fuel on board to do so, the liquid oxygen on board was only enough to achieve a roughly 95% likelihood of completing the second burn, so Falcon 9 did not attempt a restart."
The satellite, built by New Jersey-based satellite firm Orbcomm, was supposed to have been carried into a higher orbit by the Falcon 9's second stage. Orbcomm said Monday that its satellite was circling in a lower-than-intended orbit, and it was trying to determine whether the satellite's own propulsion systems could carry it the rest of the way up.
SpaceX said it was studying flight data with NASA to figure out what happened, "and we will apply those lessons to future flights." Initial readings indicated that an engine fairing broke apart under stress, it said Monday.
Despite that problem, NASA Administrator Charles Bolden called Sunday's launch and the mission "a critical event in space flight." And SpaceX, which Musk founded in 2002, is looking beyond cargo flights to develop a version of the Dragon that would carry astronauts to the ISS. It's one of three companies, along with Sierra Nevada and aerospace giant Boeing, that NASA has chosen to work on the project.
Within the next few months, Orbital Sciences is expected to fly its own demonstration flight to the space station. Instead of using Cape Canaveral as its launch site, the company's rocket will take off from Wallops Island, off the coast of Virginia. Orbital has a nearly $2 billion contract with NASA for station resupply missions.
In 2008, NASA chose SpaceX's Falcon 9 launch vehicle and the Dragon spacecraft to resupply the space station after the space shuttle program was retired. The space agency plans to turn much of its focus toward exploring deep into the solar system.
"The $1.6 billion contract represents a minimum of 12 flights, with an option to order additional missions for a cumulative total contract value of up to $3.1 billion," SpaceX says on its website.