NASA today officially gave Endeavour the green light to launch Wednesday instead of an unmanned rocket carrying two satellites bound for the moon. Endeavour would launch at 5:40 a.m., in the middle of a 10-minute window.
NASA managers at 3 p.m. plan to update Endeavour's processing for launch, including repairs to a launch pad vent line that leaked hydrogen gas during a first launch attempt Saturday. You can watch the status briefing live by clicking on the NASA TV still image on the right side of the page.
At 1 p.m. briefing, managers of the moon mission, which had been scheduled to launch Wednesday afternoon from Cape Canaveral Air Force Station on an Atlas V rocket, announced they had given up their launch opportunity to the shuttle program.
"They are tracking well to their rework with the (ground carrier plate) seal," said Chuck Dovale, NASA's launch director for the unmanned mission.
The images above show technicians at Kennedy Space Center's launch pad 39A reattaching a vent line to Endeavour's external tank.
The line leaked hydrogen gas while the shuttle was fueled for a first launch attempt Saturday. A vavle and seals were replaced.
Dovale said it's possible the Atlas V could lift off as early as Thursday afternoon, an option currently under review by the Air Force's Eastern Range, which must reconfigure its tracking and range safety systems after the shuttle launch.
If Thursday is too soon, Friday would be the next opportunity, and Saturday the last before standing down until June 30.
Managers for the mission's secondary payload, the Lunar Crater Observation and Sensing Satellite, or LCROSS, prefer to fly as soon as possible.
The spacecraft will guide the rocket's Centaur stage into a collision with a shadowed crater on the moon's south pole, fly through the plume it creates to collect data and then crash four minutes after the first impact.
If the launch is delayed much longer, managers might have to choose a different crater for the impacts, and it would be viewable by fewer people on the ground in the United States.
"For that reason, we'd rather go sooner than later," said Dan Andrews, LCROSS project manager.
4 comments:
Hi James!
Could you please explain, in layman's terms, why NASA can't lanuch the shuttle AND the lunar probe on the same day? Does it require the same lanuch crew to fly both rockets? Are there specific safty criteria that would be violated by having two fueled vehicles read on the same day?
I guess it is rocket science, after all.
Thanks!
Rick Steele
Sarasota, Florida
Rick:
It basically comes down to the Eastern Range capability to support launches of different vehicles flying different trajectories.
The range provides launch vehicle tracking and range safety services for all launches from Kennedy Space Center and Cape Canaveral Air Force Station. Bottom line is it takes 24 to 48 hours to reset, calibrate and test radars that are used to track shuttles and rockets that are flying different trajectories......
Todd
Rick:
Basically this comes down to Eastern Range tracking turn-around capabilities.
NASA's shuttle Endeavour will be flying a northeasterly trajectory to get into an orbit inclined 51.6 degrees to the equator -- not so coincidentally the same orbit the Russians fly in to from Baikonur Cosmodrome in Kazakhstan.
The Atlas V-LRO will be flying a due east trajectory to get into an initial orbit inclined 28.5 degrees to the equator.
So right now all the Air Force tracking radars and range safety assets are set up for a shuttle mission flying to that highly-inclined, 51.6 degree orbit.
Once the shuttle either launches or scrubs, the Air Force will have to reset, calibrate and test the radars and other range assets to make certain they are ready to support a rocket flying a due east trajectory inclined 28.5 degrees to the equator.
That reset typically takes 24 to 48 hours.
Since the shuttle is set for an early AM launch, and the LRO is targeting a late-afternoon/early evening liftoff, the range folks say they will be able to reset all the radars and whatnot for an Atlas V-LRO/LCROSS launch attempt early Thursday evening....
Hope that helps,
Todd
This means that most of the U.S. will not be able to view the LCROSS crash into the moon, as we would have had the launch been on Wednesday.
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