SpaceX launches Dragon on 2nd space station resupply mission
March 1, 2013  -  A commercial cargo spacecraft was launched Friday (March 1) on a NASA-contracted flight to resupply the International Space Station (ISS), but an issue with the capsule's maneuvering thrusters has called the flight's success into question.
Space Exploration Technologies (SpaceX) launched their Falcon 9 rocket topped with a Dragon cargo capsule at 10:10 a.m. EST (1510 GMT) on Friday (March 1) from Complex 40 at the Cape Canaveral Air Force Station in Florida. The launch, according to the company, proceeded as planned and the Dragon was placed into its intended orbit.
Soon after separating from the rocket however, the Dragon experienced a problem with a pressurization line that prevented three of the capsule's four thruster pods from operating. The Dragon is outfitted with a total of 18 jets  -  two pods with four and two with five  -  that are used to adjust the capsule's attitude and approach to the station.
"We noticed after separation that only one of the four thruster pods engaged or was ready to engage," Elon Musk, SpaceX's CEO, told reporters during a post-launch telecon. "And then we saw the oxidizer pressure in two of the four tanks was low. And so we spent several hours trying to fix the problem and we think we have. If that's the case, it is certainly going to be a huge relief and we'll be really glad... and hopefully be able to deliver the cargo that we intended to deliver."
The pressurization issue, which Musk said may have been due to a blockage of some type, also held up the deployment of the Dragon's two power-providing solar arrays, though they were ultimately extended successfully.
As of Friday afternoon, SpaceX had re-engaged all four of the thruster pods.
"Thruster pods one through four are now operating nominally," Musk reported on Twitter. "Preparing to raise orbit. All systems green."
The gumdrop-shaped Dragon had been scheduled to pull up to the space station early Saturday morning, where the crew would use the outpost's robotic arm to capture the capsule and berth it to the side of the station. NASA has confirmed that a Saturday arrival is no longer an option, but the Dragon may be able to reach the orbiting complex on Sunday.
"Fortunately, we have quite a bit of flexibility in our berthing date," said Michael Suffredini, NASA's manager of the International Space Station program.
Suffredini said NASA will review SpaceX's understanding of why the thruster pods initially failed before approving the Dragon to approach the station.
Packed with more than 1,200 pounds (540 kilograms) of crew equipment, supplies and science experiments, the Dragon is also carrying a surprise snack for the six astronauts and cosmonauts living on the orbiting laboratory. The previous delivery brought ice cream; this time, SpaceX chose to send fruits from the orchard of an employee's father.
"It is a little bit healthier, I think, than the one that NASA sent last time," SpaceX president Gwynne Shotwell told collectSPACE.com, adding that it was more than just apples.
If it successfully reaches the station, the Dragon will be unpacked by the crew and then repacked with science experiment results and spent equipment before it is sent back to Earth for a Pacific Ocean splashdown about 25 days later.
The Commercial Resupply Services-2 (CRS-2) mission marks the fourth flight of SpaceX's Dragon and will be the third to visit the space station. The Hawthorne, Calif.-based company also has an agreement with NASA to further develop the Dragon to launch astronauts to the space station.
Photos: collectSPACE.com / Robert Z. Pearlman