Saving the Hubble Space Telescope may be too dangerous and cost too much, U.S. legislators said Wednesday after hearing from scientists who are divided about what to do with the aging camera.

The chairman of a congressional science committee said the government needs to decide whether the telescope is worth the cost of repair – estimated at up to $2 billion US.

"We have to make hard choices about whether a Hubble mission is worth it now, when moving ahead is likely to have an adverse impact on other programs, including quite possibly other programs in astronomy," said Sherwood Boehlert, a Republican congressman from New York.

It may cost up to $2 billion US to repair the Hubble Space Telescope.
It may cost up to $2 billion US to repair the Hubble Space Telescope.

Hubble, which hovers about 600 kilometres above the Earth and circles it every 95 minutes, has beamed back crucial information since it was launched in 1990.

Hubble's images let astronomers pinpoint the age of the universe at 13.7 billion years and discover a mysterious force called dark energy, which may oppose gravity and allow the universe to expand.

The U.S. space agency, NASA, has sent four repair missions to Hubble but experts say they need to send another one because batteries and gyroscopes will likely fail within a few years.

NASA originally intended to send a space shuttle crew for the servicing mission, but decided after the Columbia shuttle disaster that it was too risky for astronauts.

Officials from the agency proposed using robots, and the Canadian Space Agency's Dextre robot was said to be the leading candidate.

However, a U.S. National Academy of Sciences committee concluded in December that using a robot would take too long and might not work.

The panel, which passed on its report to the congressional science committee, concluded that sending astronauts to fix Hubble was no more risky than sending them to the international space station.

"The crew risk of a single shuttle mission to Hubble is very small," the scientific panel's chairman, Louis Lanzerotti, told the legislators Wednesday.

If Hubble doesn't get repaired, NASA has agreed to use a robotic spacecraft to steer it into the ocean by 2013.