The U.S. space agency, NASA, continues work on improving the safety of the space shuttle, before the fleet of orbiters resumes its visits to the international space station next year. Agency officials say they have made significant progress toward launching a safe mission in March or April.
U.S. space shuttle managers are completing a long list of recommendations made one year ago by aviation safety experts, who investigated the loss of the shuttle Columbia seven months earlier.
Columbia broke apart on its final orbit, and all seven astronauts died because debris from an external fuel tank had punched a hole in its wing during launch days before, causing the wing to melt from hot atmospheric gases during re-entry.
To prevent another loss, the accident investigators called for 15 safety improvements they said should be completed before flights resume. NASA officials say they have met five, and have made progress toward the other 10, which must be met by December, if a shuttle is to lift off early next year.
NASA administrator Sean O'Keefe said recently that the experts' recommendations set out only broad safety aims, leaving NASA to decide how to accomplish them.
"What we are going through right now is a very exhaustive effort,? Mr. O'Keefe said. ?My guess is it's taking a longer period of time than if those answers had been prescriptive, because, in the end, everyone who is participating in it knows we must own that answer. On the day that the launch occurs, we will know that we have done our level best to achieve that."
Shuttle officials say the main safety priority has been reached. On the external fuel tank where hard insulating foam tore off and cracked Columbia's wing during liftoff, heaters have been substituted to prevent ice build up caused by the frigid fuel inside. They are trying to improve foam application in other areas of the tank.
Air, sea and ground cameras and radar will look for debris during shuttle launches, new wing sensors can detect a debris strike, and for the first time, astronauts will be able to patch small holes in orbit. Yet by the time of the next mission, they will not be able to fix severe damage of the type that doomed Columbia, and stronger protective wing panels have not been developed to guard against that possibility.
Also proving difficult is development of an ability to inspect the shuttle in orbit with a camera mounted on a boom. Although this is not one of the 15 requirements for a return to flight, NASA head Sean O'Keefe says it is important.
"Achieving stability on this arm is not happening with the pace, which we would like. It has been described to me by every engineer working on this as the equivalent of trying to take a photo, while you're moving the camera. So, what you get is a very jittery shot,? Mr. O'Keefe said.
Mr. O'Keefe says a shuttle can never be completely risk free, so if astronauts ever again face danger, new procedures call for a backup shuttle to be prepared to fly a rescue mission. An endangered shuttle can also dock with the space station, and the can be crew transferred.
Because the station can support only six people, station program manager Bill Gerstenmaier says life support systems would have to be maximized for the addition of a shuttle crew for a long period. Equipment would also have to be transferred out of the station to the troubled shuttle to provide accommodations.
"The general habitation is not desirable, but it is acceptable, and there is enough room overall on station. It's not going to be, maybe, the most comfortable in the world, but it is a survival capability," Mr. Gerstenmaier said.
NASA has also improved its attitudes about safety. The Columbia accident investigators criticized its leadership for not being sufficiently concerned about mission safety and ignoring safety concerns of lower level employees, especially during Columbia's flight. But a private consultant hired by NASA to help reform management says the organization is opening communication channels to its workers, and changing its safety culture.
Psychologist Thomas Krause of Behavior Science Technology, Incorporated said "NASA leadership has taken on an aggressive set of organizational changes and initiatives."
Mr. Krause adds that "There has been extensive agency-wide dialog of the causes of the Columbia tragedy and the remedies. There has been leadership evaluation and training, employee involvement, emphasis on communications, and major structural reorganization."
Mr. Krause says workers are no longer afraid to speak up, and he gives NASA's safety consciousness a grade of 70 or 80 percent. But he says it must do better because of the complexity and risks of its work.