http://www.floridatoday.com/apps/pbcs.dll/article?AID=/20060723/NEWS02/607230325
CAPE CANAVERAL - The safe conclusion of Discovery's mission brings NASA's shuttle program to its next challenge: Can an agency that has flown two shuttle missions in three-and-a-half years now shift into higher gear and execute 16 of them in four years? History, in the long-term, says NASA can do it. On average -- even including two years-long groundings of the fleet after catastrophic accidents in 1986 and 2003 -- Kennedy Space Center has launched four to five shuttle missions every year since the first one in 1981. Flying 15 missions to the International Space Station and one to the Hubble Space Telescope during four-and-a-half years is definitely doable. The space agency's difficulty getting shuttles off the ground since the Columbia accident is not exclusively limited to problems with the external tank's foam insulation. Rather, a host of post-Columbia safety requirements -- most notably not being able to fly at night -- exacerbated the situation. In the simplest terms, to fly 16 times between now and 2010, NASA needs the flexibility to launch the space shuttle day or night. "We need to do that to build the station," NASA Administrator Mike Griffin acknowledged in a preflight interview with FLORIDA TODAY. Mike McCulley, the former astronaut who now leads the company that operates the shuttle fleet day-to-day, agrees that the agency needs to relax some of the post-Columbia restrictions placed on flying the shuttles while not sacrificing safety. "We have to make some changes to the way we do requirements," he said. The first relaxation is almost certain to be lifting the ban on nighttime launches. Currently, NASA wants to launch shuttles during daylight, when it can get the clearest possible pictures of the rising vehicle and its external tank foam insulation. The idea is to be able to document whether design changes have reduced the amount of foam coming off the tank and presenting a debris threat to the orbiter's delicate heat-shielding -- the flaw that doomed Columbia and seven astronauts. How does that hinder NASA's ability to fly frequently? There are only certain times on any given day when a shuttle blasting off from Brevard County can be targeted to dock with the International Space Station, orbiting more than 200 miles overhead and whizzing around the Earth at more than 17,000 mph. Certain days of the year, the times when the shuttle can launch to the station do not occur at the same times when the vehicle and its external tank will be lit properly during launch and when the tank is jettisoned. The periods of time when all of those conditions do exist have defined NASA's launch windows. The next one stretches from about Aug. 28 to about Sept. 13, though some schedule conflicts with the Russians' flight schedule practically means shuttle Atlantis can't launch after Sept. 7. The only other launch windows before December are a couple lasting no more than a few days each in October and November. Eliminate the daylight launch rule, and NASA suddenly has a much higher chance of getting off its two planned missions before the end of this year. The agency's leaders have said they may lift the daylight restriction after one more flight if the tank's foam continues to perform as expected and tools used to inspect the orbiter in space prove reliable. Discovery's flight is evidence things are turning in that direction and everyone from the astronaut corps to top management celebrated that. "The shuttle is back," shuttle program manager Wayne Hale said Tuesday. Steve Wallace, a former member of the Columbia Accident Investigation Board, said he is confident that NASA can fly the shuttle safely. However, he is not as confident that it is possible to fly all of the missions on NASA's plate before shuttle retirement in 2010. Wallace, who also served a stint on the agency's independent Aerospace Safety Advisory Panel, says post-Columbia safety restrictions, the availability of only three orbiters and limited financial resources could slow the agency's pace of flights when compared to the historical average that Griffin often cites as evidence it can be done. "We have funding limits, and it doesn't look like it's going to add up," Wallace said. ". . . It gets harder and harder for me to see how we're going to complete that space station by 2010." NASA could push harder to meet the goal, but Wallace said the internal discussions he has been part of in his role as an investigator and a safety watchdog suggest to him that no one will be willing to cut any safety corners to accelerate the flight rate. "I still think this Columbia loss is fresh in people's memories, and there is really is an awareness and a fear of letting schedule pressure cause that kind of thing to happen again," Wallace said. Reply with a "Thank you" if you liked this post. _____________________________ MEDIANEWS mailing list [email protected] To unsubscribe send an email to: [EMAIL PROTECTED]
