14 DAY TRIAL // The shuttle Discovery is ready for launch, but the talks about the possible risks are still at an all time high. And the favorite subject is the danger posed by ice falling off the shuttle's external tank during liftoff, which was the main cause of Columbia's accident in 2003.
Successful resolution of the ice issue is considered to be the last major issue the shuttle program needs to clear before NASA Administrator Michael Griffin approves the return of the space shuttle fleet to service, this being the major reason for which Griffin postponed Discovery's launch from May to July.
Seven months after the Columbia accident, the Columbia Accident Investigation Board (CAIB) concluded that foam insulation broke off during liftoff from the shuttle's external fuel tank, striking and cracking a panel on the orbiter's wing. When the shuttle re-entered the Earth's atmosphere, searing hot gases seeped into the wing, thus leading to the spacecraft's explosion.
As CNN reports, The Stafford-Covey Return to Flight Task Group has indicated NASA has met 12 of 15 of the CAIB recommendations for return to flight. The only other unmet CAIB recommendation has to do with NASA's ability to repair an orbiter's "thermal protection system" (TPS) during orbit. But members of the task group have already indicated that this is not a sufficient reason to impede the shuttle's return to flight.
The Stafford-Covey group has also approved endorsed NASA's "safe haven" plan, which consists of equipping the International Space Station in order to provide shelter to a shuttle crew in the case an orbiter is irreparably damaged upon liftoff and cannot safely re-enter Earth's atmosphere. If this happens, a shuttle crew would have to live aboard the station for six to eight weeks while another orbiter is prepared to undertake a rescue mission.
No date has been set for the possible launch. NASA has an opportunity from July 13 to July 31 to conduct a daytime launch on a rendezvous trajectory with the space station. If Discovery does not launch during that window, shuttle managers would have to wait until September 9 for acceptable lighting conditions to return.