The U.S. space agency says it will send space shuttle astronauts one more time to extend the life of the Hubble Space Telescope. The decision reverses one made by NASA's previous management two years ago, which caused a scientific and public outcry.
Astronauts have repaired and upgraded the Hubble Space Telescope four times during its 16 years in orbit and a fifth visit had been planned for last year. But the 2003 loss of the space shuttle Columbia during re-entry put shuttle flights on hold.
A year later, the NASA administrator at the time, Sean O'Keefe, canceled the Hubble servicing mission as too risky for a shuttle crew. The possibility for a robotic repair visit was also eliminated when studies showed it to be too expensive and too complex to prepare by 2007, the time it was thought the telescope would fail because of weakening batteries and dead stabilizing gyroscopes
Now, the present NASA chief, Michael Griffin, has overturned the decision not to send a shuttle crew back to Hubble.
"Today I'm here to announce a much more pleasant decision on behalf of the agency," he said. "We are going to add a shuttle servicing mission to the Hubble Space Telescope to the shuttle's manifest, to be flown before it [the shuttle] retires."
Griffin was interrupted by a standing ovation from the employees of the NASA technical center near Washington that designed and built the telescope and planned the four previous maintenance missions.
"They have all four gone as flawlessly as one could ever imagine and I am fully confident that this fifth mission will go as flawlessly as any of us can imagine and I'm very proud of your efforts to do so," he said.
Griffin says the shuttle Discovery will take a crew of seven to restore Hubble and add new equipment as early as May 2008 to keep it operating until 2013. He points out that the mission can wait that long because NASA engineers have devised ways to prolong the life of the telescope's batteries and gyroscopes. Even if they fail by 2008, he says the telescope can be protected in a so-called safe mode until astronauts arrive.
Reaction to Griffin's decision has been enthusiastic. Barbara Mikulski, a U.S. senator from Maryland, the location of the NASA technical center, is exultant.
"It's a great day for science. It's a great day for discovery," she said. " It's a great day for inspiration because that is one of the things that Hubble has meant to so many people."
The astronomical community is equally cheered by Griffin's decision.
"I couldn't be happier," says Michael Bakich, a senior editor at Astronomy magazine. "I view the Hubble Space Telescope as one of the great machines of all time. The number of discoveries it has made and what we have learned are just incalculable."
NASA administrator Michael Griffin says the agency has gained confidence since the Columbia disaster that it can conduct a Hubble servicing mission without more risk than a shuttle visit to the International Space Station. He notes that NASA has developed techniques to inspect and repair shuttles in orbit, relieving fears that a shuttle could not survive the kind of damage that doomed Columbia, a small hole in its wing incurred when launch debris slammed into it.