The space shuttle Discovery's successful landing in the darkened desert of California's Edwards Air Force Base shortly after 8 a.m. ET ended what turned out to be one of the safest missions in the program's historyand one of the most precarious following the disastrous Columbia re-entry two and a half years ago.
At mission control inside the Johnson Space Center in Houston, the sense of calm was noticeably higher than that during liftoff nearly a month ago when two minutes into the flight it was learned that foam debris which doomed Columbia had also fallen from Discovery's detachable fuel tank.
The sound of twin sonic booms just after 8 a.m. ET never sounded so good to NASA, signalling re-entry into the Earth's atmosphere after the craft and its heat shield tiles survived the hottest part of the descent at some 3,000 degrees Fahrenheit. "We're happy to be home," Discovery commander Eileen Collins transmitted to NASA from the Edwards runway. NASA was happy tooalthough everyone would have been even happier had they landed in Florida, as scheduled. Unfortunately, cloud cover and lightning forced the landing in California.
NASA extended the mission one day in the hopes of landing in Florida. Now the shuttle must be transported back to Florida where it will be ready as Atlantis's backup for a mission tentatively scheduled for September. Had Discovery touched down in Florida, of course, it would have been easier to stick to their time-table. Before that next mission, NASA must continue to answer questions about foam debris. The growing consensus, however, is that personnel walking on the craft during preparations may have accidentally dented the external fuel tank, leading to the dislodged foam. In other words, NASA is beginning to think that is was not a problem with tank design.
The high degree of safety is a direct result of the new ability to examine the shuttle in flight with remote cameras. And while the dislodged foam caused much consternation at the space agency, Discovery had the least loss of foam when compared to the other shuttle launches. Still, the first-ever space walk to the underside of the shuttle was deemed necessary to pull cloth from between tiles, again to err on the side of caution. And despite the smaller amount of foam debris hits, NASA admits that the largest chunk to fall could have been equally disastrous had it hit the shuttle's wing or a heat-shielding tile elsewhere on the craft.
Even the shuttle's flight path home was done for safety, in an eerie sort of way. The path to Florida did not go over the Southeastern United States, where Columbia broke up,but instead was routed via the Gulf of Mexico. The path to Edwards specifically avoided flying over the city of Los Angeles.
NASA has already announced it will not fly another shuttle until it can ensure even greater safety, and it will tout any next shuttle mission as one more apt to capture the imagination of the public that space flight has been known for. The Discovery flight was to retrieve two tons of garbage from a space station many often forget even exists. Now, NASA must ensure it can continue to secure the existing shuttle's foam coverage if it wants to continue flights through its planned 2010 retirement; it must also design a new manned orbitor and complete the space stationall while continuing to capture America's imagination.