(sort of "off topic") : ABC News -- Why is it so tough to launch a shuttle ? .....................
Why is it so tough to launch a shuttle?
Gina Sunseri
ABC News
(12/08/06) - It's not easy to schedule a shuttle launch. There is one five-minute window each day when Earth's rotation puts the launch pad into the plane of the space station's orbit -- the launch site and the space station orbit must be in sync.
Complicating this, the shuttle can only visit the station when the "beta angle" -- the angle between the plane of the station's orbit and the sun -- ensures the shuttle-station stack will not get too hot yet still be at an angle to allow the solar arrays to function.
Complicating any attempt to launch is Florida's weather. There is a long list of rules prohibiting a shuttle launch if cloud cover is too low, too dense, or if it's too windy, too hot, too cold -- or if there is a hint of rain near the launch pad or in the flight path of the shuttle and lightning in the area, forget it.
It's an understatement to say there are thousands of technical glitches that can bring a countdown to a stop.
Public affairs officer Jessica Rye of the Kennedy Space Center said scrubbing a launch so close to liftoff costs the space agency $500,000. It happens often -- only half the shuttles launched ever lift off when first scheduled.
When launch director Mike Leinbach finally threw in the towel with five minutes left in the launch window Thursday night, he told STS 116 Commander Mark Polansky, "We gave it our best shot."
The countdown clock stopped at T-5 last night. But it could have stopped even closer to ignition. Earlier this year, Leinbach explained the launch process to ABC News:
"At T-zero, the shuttle is gonna fly. That's when the solids ignite and the shuttle is going to fly. Down to that point we can stop the countdown even if the main engines of the shuttle ignited.
"And we have done that three or four times in the history of the program. We terminated the program after the shuttle's main engines started up. It is very hazardous to do that, but we would rather be on the ground and safe than commit to flight with a plan that may be out of spec, so the computer either here in the control room or onboard the shuttle can stop the countdown all the way down to T-zero."
They did give it their best shot. Astronaut Steve Lindsey repeatedly flew weather reconnaissance flights, checking to see if the cloud cover was too dense, and conditions bounced back and forth between "go" and "no go" all evening.
STS 116 Discovery is the 117th shuttle mission, the fourth flight since the Columbia accident, the 20th flight to the International Space Station. This will be the first night launch for a space shuttle since STS 113 in November 2002.
It is billed by space shuttle program manager Wayne Hale as the most complicated shuttle mission ever because of the construction demands for the International Space Station. This crew will be rewiring the space station, which requires shutting off power to half the space station during two space walks.
"It's like living in your house while it is being rewired -- except this house is orbiting 195 miles above Earth traveling at 17,500 miles per hour," explained lead flight director Tony Ceccacci. This mission was supposed to fly in July 2003 but was postponed because of the Columbia accident.
This is one of the most diverse space shuttle crews ever. There are two African-American astronauts on this mission, and a Swedish astronaut. Five of the seven crew members are first-time fliers who have been waiting eight to 10 years to fly.
No matter what happens, NASA wants Discovery back on Earth by midnight on New Years' Eve. All three shuttles have mandatory Y2K + 7 software upgrades that NASA does not want to make while a shuttle is in flight.
Three critical spacewalks to rewire the space station are scheduled with three spacewalkers.
Engineers worry that the P6 truss won't retract (it's been on the station for six years). If that happens, then the crew can manually retract the array, or the crew can unhook it and shove it off into space. (The array is like a brand new road map -- neatly folded when you get it, but once it's opened and you need to fold it back up again, it's a problem.)
This is the second construction project on the space station in four years to install two new trusses and solar arrays. Fourteen flights are on the manifest to finish ISS, plus two which will ferry parts and supplies to the ISS before the shuttle quits flying in 2010.
The space shuttle program budget is $4.78 billion. The cost per flight is determined by the number of times the shuttle flies in a year. So if NASA flies three missions this year, the cost is $1.59 billion per mission in 2006. NASA's budget for 2006-2007 is $35 billion.
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