The Hubble space telescope, which has glimpsed billions of years back in time to the early days of galaxies, got a new lease of life in October with NASA deciding to include a service mission in its hectic schedule.
NASA officials said the mission date would be September 11, 2008. The decision took 18 months and extensive study of safety issues, NASA director Michael Griffin said. His announcement triggered half a minute of applause from workers at the Goddard Space Centre in Maryland that operates Hubble.
Without servicing, Hubble could lose its ability to take picture of galaxy formations and boiling star nebulae by next year, scientists said. A repair mission slated for 2004 was cancelled under pressure for the aging shuttles to return to flight and finish construction on the International Space Station (ISS) before the heavy-lifting aircraft are retired in 2010.
The 2003 Columbia shuttle disaster made planning for a repair mission even more difficult as NASA has spent the past two years launching test flights in its cautious return to space. The success of the test flights convinced Griffin and NASA to add a Hubble repair flight to the schedule.
The prospect that Hubble would die in space alarmed international scientists and worried schoolteachers who use Internet photographs from outer space - quasars and black holes and galaxy formations - to inspire their students. NASA investigated and then dropped the idea of sending a robot to do the repairs.
The Hubble mission will have to carry out at least four or five space walks to service the telescope and be prepared to make extra walks to repair any damage to the shuttle that occurs on takeoff.
Missions to the space station are easier because ISS crew is on hand to help inspect the shuttle. The ISS also offers up to three months refuge for visiting crew in case of an emergency.
The Hubble, which orbits 580 km above earth, offers neither. That means the shuttle would have to survive on its own for up to 25 days, with the second shuttle on stand-by at a separate launch pad for a rescue mission.
After years in planning, the $1.55 billion space telescope was released from a shuttle in 1990, only to find its vision blurred by small error, one-fiftieth of the width of a human hair in its lens. It produced blurry images barely better than those seen through Earth's cloudy atmosphere.
"Word came back that Hubble couldn't see and it needed the most expensive contact lens in world history," recalled Senator Barbara Mikulski, a powerful Democrat and one of NASA's biggest boosters.
After the repair, Hubble became one of the most scientifically productive spacecraft ever launched, peering 2.2 billion light years away into the Abell 1689 galaxy, recording the minus 270 degree Celsius background glow from the Big Bang and producing jaw-dropping images of swirling clouds of space matter in oranges, greens, yellows, reds - the Crab Nebula, the starburst Galaxy Messier 82.
NASA's decision to scrap the Hubble provoked protests in the scientific community, especially after US President George W Bush decided to divert NASA money into a $12 billion new moon programme over five years.
The space community took little consolation that Hubble's replacement, the James Webb Space Telescope, is slated for launch in 2013. That would still have left them with a three- or four-year gap with no window on the universe.
With the new mission, Hubble can last at least until 2013.