(NBC News) -- SpaceX's Falcon 9 rocket blasted off Friday to send an unmanned Dragon cargo capsule on its quickest trip yet to the International Space Station, but the company is working through a serious problem with the Dragon in orbit.
The Falcon 9 made a problem-free ascent from its launch pad at Cape Canaveral Air Force Station in Florida at 10:10 a.m. ET. A half-hour after launch, SpaceX's billionaire founder, Elon Musk, said in a Twitter update that controllers encountered a glitch involving the capsule's thrusters. "Issue with Dragon thruster pods," Musk wrote. "System inhibiting three of four [pods] from initializing. About to command inhibit override."
Each pod contains a grouping of thrusters that are used to guide the Dragon's course in orbit. Initially, SpaceX said it preferred to hold off on opening up the Dragon's power-generating solar arrays until at least two of the four thruster pods were operational. Later, SpaceX spokeswoman Christina Ra said that the solar arrays were deployed after overriding the onboard computer.
In an email, Ra said the Dragon "experienced an issue with a propellant valve" after it achieved orbit.
"One thruster pod is running," she said. "We are trying to bring up the remaining three. We did go ahead and get the solar arrays deployed. Once we get at least two pods running, we will begin a series of burns to get to station."
A news briefing is planned later Friday to discuss the status of what's expected to be a three-week resupply mission.
This is the third Dragon flight to the station: The first one, which took place last May, was a demonstration flight aimed at proving that California-based SpaceX could safely reach the space station, get hooked up, and then descend again to a splashdown. Last October's second flight marked the first of what's expected to be 12 resupply missions to the station, under the terms of a $1.6 billion contract with NASA. At that rate, each Dragon mission costs NASA about $133 million.
The Dragon's earlier flights required a couple of days for the approach to the space station. Due to favorable orbital geometry, this spacecraft could reach the station as early as 6:30 a.m. ET Saturday. However, NASA and SpaceX said the sequence of engine burns required to get to the station might have to be modified due to the thruster problem — and that could affect the schedule.
If the Dragon proceeds with the resupply mission, astronauts will use the station's robotic arm to grab the capsule from a distance of 10 meters (33 feet), and then pull it in to a port on the orbital outpost's Harmony module.
This Dragon holds more than 2,300 pounds (1,050 kilograms) of cargo, including experiments to study the growth of plants and mouse stem cells in zero-G. There are also spare parts for the station's air-recycling system, and a research freezer for preserving biological samples.
A similar freezer was loaded up with ice cream treats for the crew for last October's resupply mission, but this time, the goodies packed on the Dragon will be "a little bit healthier," SpaceX President Gwynne Shotwell said. Although she wasn't specific about what the space station's six residents would be getting, she said the treats were coming fresh from an orchard owned by the father of one of SpaceX's employees.
The astronauts are due to open up the Dragon on Sunday. It will take about three weeks to unload the craft, then load it up with more than 3,000 pounds (1,370 kilograms) of cargo for return to Earth. The Dragon is due to be unberthed for a Pacific splashdown and recovery on March 25.
SpaceX's cargo flights are meant to fill the gap left by the retirement of NASA's space shuttle fleet in 2011. Another company, Orbital Science Corp., has a separate NASA contract to begin deliveries to the space station later this year. Cargo can also be delivered to the space station on Russian, Japanese and European transports, but only SpaceX currently has the capability to bring cargo back down.
SpaceX and two other companies, Sierra Nevada Corp. and the Boeing Co., are developing crew-capable spacecraft under a separate NASA program. Those spaceships could be ready for NASA's use as early as 2017. In the meantime, U.S. astronauts have to ride on Russian Soyuz capsules at a cost of about $60 million per seat.
Courtesy NBC
