SpaceX says it has resolved the problem that held up liftoff of an unmanned Dragon cargo ship to the International Space Station — and is shooting for another launch attempt on Friday.
NASA confirmed the launch date on Wednesday, two days after a last-minute leak on SpaceX's Falcon 9 rocket delayed the mission. Stormy weather, however, is forecast for launch time at 3:25 p.m. ET Friday. Saturday is the backup launch date.
Because of the shifting scenarios for SpaceX's launch, Mission Control has rescheduled a spacewalk to replace backup computer that failed late last week. The prime computer has been working fine, but NASA wants to get a new backup installed outside the station as soon as possible. These computers control the pointing of the radiators and solar wings, among other things.
NASA astronauts Rick Mastracchio and Steven Swanson had been preparing for a Tuesday spacewalk, but now the outing will take place either on Easter Sunday or next Wednesday, depending on when — or if — the cargo ship flies. The Dragon contains more than 2 tons of supplies, including material that would prove useful for the repair but is not essential.
SpaceX said Monday's helium leak was caused by a bad valve in the system used to separate the rocket's first stage. Although a backup valve was working properly and could have supported the flight, SpaceX followed its own policy of canceling a launch in the event of equipment problems such as this.
The faulty valve is being replaced, the private company said in a statement, and inspections are under way to see if anything else might be wrong.
SpaceX and another commercial venture, Orbital Sciences Corp., resupply the space station under NASA contracts that have a combined value of $3.5 billion. If SpaceX isn't flying by Saturday, then Orbital Sciences will move to the front of the launch line, with a shipment in early May, officials said. That would push the Dragon launch into June.