WASHINGTON - Astronomers around the world are holding their breath this week as NASA prepares to launch its most challenging and perilous mission yet to repair and upgrade the 12-year-old Hubble Space Telescope.
In five days of grueling spacewalks, four astronaut-mechanics will work to ensure the future of what is still the world's premier astronomical observatory. They hope to extend a $6 billion mission that has produced thousands of astonishing images and expanded man's understanding of some of the universe's deepest mysteries.
Few will be following their progress more intently than the hundreds of scientists and engineers at the Space Telescope Science Institute in Baltimore, who have invested their careers in Hubble's success.
Astronomer Mario Livio, head of the institute's science division, compared the institute's anticipation of this fourth Hubble servicing mission to childbirth.
"By the time your fourth child is born, yes, you're nervous about this. But you've seen it going well the first three times, so you have a certain confidence things are going to go well," he said.
Even so, he said, as the countdown goes to zero this week, "the level of nervousness will go up."
Seven astronauts are to board the newly refurbished shuttle Columbia for a dawn launch Thursday. In 37 hours of spacewalks beginning March 3, they will:
Replace the last of Hubble's original instruments with a state-of-the art camera that promises a tenfold improvement in the telescope's "discovery potential."
Try to install an experimental refrigeration system for an infrared camera that broke down in 1999 when it ran out of coolant.
Install new, more powerful solar panels and replace a faltering piece of Hubble's pointing system.
And, in their most critical assignment, astronauts will cut all electrical power to the telescope for the first time to replace a circuit box that was never designed to be disconnected in space. No one is sure whether the telescope's instruments will work when the power goes back on.
"Nervous as hell." That's how Ann Kinney, NASA's director of astronomy and physics, described herself as the launch of the fourth Hubble servicing mission neared.
During 12 years in orbit, the 12 1/2 -ton telescope has vastly expanded scientific understanding of the universe. On the short list of its accomplishments are:
Confirmation of the existence of black holes.
