NASA Sets Wednesday for Shuttle Launch
NASA on Tuesday plans to complete repairs to some launch pad equipment and resume a countdown to the launch of space shuttle Endeavour, now set for 5:40 a.m. Wednesday.
Mission managers are confident that a replaced valve and seals will prevent another hydrogen gas leak while the shuttle's external tank is loaded with fuel, a process scheduled to start at 8:15 p.m. Tuesday.
A vent line that leaked at unacceptable levels scrubbed a first launch attempt Saturday.
"The repair is work is going well," NASA Test Director Steve Payne said Monday afternoon at Kennedy Space Center. "Our teams have been working very hard over the last couple of days to get this piece of equipment fixed."
The launch of two satellites from Cape Canaveral to the moon, previously scheduled for Wednesday afternoon on an Atlas V rocket, will now follow Endeavour's launch attempt as early as Thursday or Friday.
On Monday, Kennedy Space Center workers reattached the vent line to Endeavour's external tank. The line routes excess gas to a flare stack where it is burned off safely.
If Tuesday evening's fueling operation is successful, Endeavour's seven-person crew would climb into the shuttle at 2:20 a.m. Wednesday.
Led by commander Mark Polansky, the crew is scheduled to fly a 16-day mission to the International Space Station, where they'll complete construction of Japan's Kibo science lab.
The weather forecast for Wednesday is good, with only a 20 percent chance of conditions that could stop the launch.
But if another leak or some new problem arises, the mission would probably be delayed until July 11, unless NASA considers shortening it.
For several weeks, the sun's angle to the space station will be too weak to provide enough power or dispel enough heat to support the shuttle mission.
The plan to launch Endeavour on Wednesday wasn't confirmed until Monday afternoon, when NASA settled the scheduling conflict between the shuttle and lunar missions.
"If you've spent any time on the Space Coast and monitoring launches, you notice that they tend to attract each other, and we've got that very situation here," said Chuck Dovale, NASA launch director for the unmanned mission.
If the shuttle countdown scrubs before midnight Tuesday, the satellites could depart Cape Canaveral as early as Thursday afternoon.
Otherwise, opportunities would be available Friday and Saturday, weather permitting.
The longer the launch is delayed this week, the fewer people in the United States will be able to see planned collisions on the moon involving the rocket's secondary payload and the rocket's upper stage, limiting opportunities for general viewing and science observations.
"For that reason, we'd rather go sooner than later," said Daniel Andrews, the mission's project manager.