After 19 years of service, during which time it has provided the most eye-popping images ever of galaxies, nebulae and, most recently, of a planet orbiting an alien star, the Hubble Space Telescope is suffering the pains of old age.
It’s unsteady, with only half its gyroscopes working, and several key science instruments are broken. To restore it to its former glory, NASA today plans to launch the fifth and final repair mission to the ailing orbiting telescope.
The mission is unusually risky, even by space travel standards, involving five spacewalks and extended time in the debris-riddled layer above Earth, where even a small collision with space junk could render the shuttle useless.
Top NASA officials say they have done everything they can to ensure the safety of the crew of the shuttle Atlantis, from flying the orbiter upside down and backward to minimize the danger of being struck in a vulnerable place by space debris to having a second shuttle on the launch pad in case a rescue mission must be mounted.
“This is going to be an extremely challenging mission,” said shuttle pilot Greg Johnson.
But if successful, the mission will leave the telescope with six new gyroscopes, six fully charged batteries, and four repaired or replaced cameras and spectrographs, including the workhorse wide-field camera No. 2 that was responsible for some of Hubble’s most dramatic images.
The repairs will keep Hubble functioning at peak efficiency at least through 2014, by which time the next-generation James Webb telescope is scheduled to take its place. Upgraded instruments will allow the refurbished telescope to look back in time to the very beginnings of the universe.
“This will be our first realistic chance of detecting the first stars and galaxies that formed” right after the Big Bang, almost 14 billion years ago, said astronomer Matthew Malkan of the University of California, Los Angeles, whose team will be among the first users of the refurbished instrument.
Malkan estimates that the reborn Hubble will be 100 times as powerful as it was when it was carried to orbit in April 1990.
It might even be powerful enough to find the current “holy grail” of cosmology – the source of the dark matter and dark energy that is thought to make up as much as 96 percent of the universe. Although neither has been detected directly, scientists believe they must exist to explain the behavior of galaxy clusters, as well as the fact that the expansion of the universe is speeding up.
The mission is not without controversy. In fact, it was canceled after the shuttle Columbia disaster in 2003, out of concern that a problem with Atlantis could leave the crew stranded in space. NASA Administrator Sean O’Keefe declared then that the only safe destination for the shuttle fleet was the International Space Station, which could offer a haven to the crew of a damaged shuttle.
It took the intervention of Congress, which earmarked money to NASA with the restriction that it could only be used on a Hubble repair mission, and the appointment of a new administrator, Michael D. Griffin, to get the mission back on the manifest.
“I thought this was a mission we ought to be doing,” said Griffin, who recently left the agency for a teaching position at the University of Alabama, Huntsville. “For the cost of one shuttle mission, we get a chance to have a brand new telescope in Earth orbit.”