The Planetary Society Blog
By Emily Lakdawalla
LRO & LCROSS: Ready to Roll to Pad 41
Jun. 17, 2009 | 21:03 PDT | Jun. 18 04:03 UTC
by Ken Kremer
The million pound thrust Atlas V rocket which will blast NASA's piggybacked Lunar Reconnaissance Orbiter (LRO) and Lunar Crater Observation and Sensing Satellite (LCROSS) to the Moon is set to be rolled out from the Vertical Integration Facility to the pad at Space Launch Complex 41 today at Cape Canaveral Air Force Station, Florida. LRO launch had been postponed 1 day to allow one last flight opportunity for Shuttle Endeavour in June.
Today's planned launch of Endeavour from Pad 39 A at the Kennedy Space Center to the International Space Station was scrubbed at 1:55 AM this morning. Intermittent leaks were again detected with the gaseous hydrogen venting system outside the shuttle's external fuel tank similar to the one which stopped Endeavour's launch on Jun 13. The fueling itself had been delayed several hours due to the nearby threat of thunderstorms. Venting of excess hydrogen is required to prevent accumulation of dangerous vapors.
The Endeavour countdown had successfully resumed as planned on Tuesday Jun 16 at the T-minus 11 hour mark and was proceeding normally until hydrogen leaks of up to 40,000 to 60,000 ppm were detected. NASA plans a full investigation to ascertain the ‘root cause' of the hydrogen leaks which have marred 3 of the last 5 shuttle launch attempts.
Following the shuttle scrub, staff at the Air Force Eastern Range immediately set to work and determined that all of the complex range telemetry and tracking systems could be reconfigured in time to support a June 18 launch of LRO & LCROSS. Because of the late night scrub and short time interval there was a chance the Eastern Range would not be able to support launch until June 19.
On Thursday, June 18 there are three one second launch windows for the Atlas 5 in the late afternoon at 5:12 PM, 5:22 PM and 5:32 PM EDT. The current weather forecast remains at 60% favorable. Afternoon thunderstorms and scattered clouds are the main weather threat to launch and are normal conditions for this time of year in Florida. In case of a 24 hour postponement, the favorable weather forecast rises slightly to 70% favorable with launch opportunities at 6:41PM, 6:51PM and 7:01 PM.
Check out my earlier reports: LRO & LCROSS Up-Close Tour, LRO & LCROSS Up Close Tour: Part 2, Hunting for Lunar Water and LRO & LCROSS Up Close Tour: Poised on Atlas V Rocket at Launch Complex 41
|
[ what is this? ]