The Air Force and United Launch Alliance plan to hold a flight readiness review Wednesday to set the launch date for a next-generation military communication satellite from Cape Canaveral Air Force Station. A Friday liftoff is targeted for an Atlas V rocket carrying the Global Wideband SATCOM-2 spacecraft.
The launch window Friday would run from 8:31 p.m. to 9:33 p.m.
A faulty valve on the rocket's Centaur second stage led to an oxidizer leak during fueling that scrubbed a March 17 launch attempt.
The valve was replaced late last week with a slightly different one, and officials say it has performed well during initial leak tests. The next test will come during the loading of cryogenic propellants on launch day.
ULA is expected to complete in a week or two an investigation into the root cause behind the valve leak, which has not been determined.
The valve in question had exhibited some leakage during a wet dress rehearsal, but within acceptable parameters, said Mark Wilkins, ULA's vice president overseeing the Atlas V program.
"We do want to close this investigation, and depending on the findings there's a potential that it could affect our future missions," Wilkins said. "Certainly we'll be looking much more at any valves that have any out-of-family leakage prior to installing them."
However, Wilkins said ULA has plenty of back-up valves in stock for the Centaur's RL-10 engine.
The Atlas V must launch Friday for NASA to maintain a targeted May 21 liftoff of its unmanned Lunar Reconnaissance Orbiter on another Atlas V, a date that would have no contingency for delays, a NASA spokesman said.
May 22 and May 23 are also possible dates, or NASA could consider slipping the launch to early June. A decision will be made after the WGS launch.
An Air Force weather forecast released today shows a 40-percent chance of favorable launch conditions on Friday, and a 70-percent chance on Saturday. You can read the forecast here.
And here's a ULA mission booklet with more background about the launch.
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