NASA to cut off Hubble telescope

By Michael Cabbage
The Orlando Sentinel

	NASA / AP The Hubble Space Telescope is shown following its release from the space shuttle Discovery in this 1997 photo.
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NASA administrator Sean O'Keefe told project scientists the decision was made to minimize risk to shuttle crews in the wake of last year's Columbia accident.

After the accident, an investigation board recommended that astronauts have the capability to inspect and make repairs to the shuttle's thermal protection system when not docked to the international space station. The difficulty of developing that capability for a single shuttle flight not bound for the station, combined with this week's decision to retire the fleet by 2010, helped drive the decision.

"This was a very tough decision for NASA and the administrator," said John Grunsfeld, NASA's chief scientist and an astronaut who flew on two previous Hubble servicing missions. "To respond responsibly to the Columbia Accident Investigation Board's recommendations that we have inspection and repair techniques would have involved the development of a tremendous amount of technology that looks like it would have been too big of a challenge."

Renowned as one of the most important science instruments ever built, the telescope has orbited 375 miles above Earth since its launch aboard the shuttle in 1990. Since a flawed mirror was replaced by spacewalkers in 1993, Hubble has captured unprecedented images of more than 25,000 celestial targets ranging from nearby planets to distant galaxies. The telescope is considered one of NASA's greatest triumphs.

	AP, 1999 The Hubble Telescope captured an image of the spiral galaxy NGC 4414, among other celestial targets.

O'Keefe's decision came two days after President Bush ordered NASA to refocus its priorities on launching a manned mission to the moon by 2020. As part of the plan, the shuttle will be retired as soon as the space station is completed. All remaining missions will be bound for the outpost.

The fifth servicing flight aboard the shuttle tentatively was scheduled to lift off by 2006 and would have kept Hubble operating until about 2010. Without it, researchers estimate the telescope likely will stop working by 2008.

"We're hoping that with the gyroscopes that are currently on the telescope and the batteries — those are the two weak areas — that we should be able to keep the telescope running through 2007, perhaps longer," Grunsfeld said.

The telescope's batteries are expected to last until 2008. However, Hubble is equipped with six gyroscopes that keep the telescope stable while doing observations. Four gyroscopes currently are operational. Three must work for Hubble to operate.

Hubble is expected to leave orbit and fall to Earth around 2011 without a reboost from the shuttle. NASA plans to launch a robot craft before then that will lock onto the telescope and help crash it safely into the ocean. A next-generation space telescope is expected to launch around 2012.

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