Hubble analyzer fixed, but not without headaches

— -- On a marathon spacewalk Sunday, two astronauts overcame repeated obstacles to make the second of two historic repairs to the Hubble Space Telescope.

The efforts paid off: Hubble's $166 million chemical analyzer, dead for nearly five years, came back to life after astronaut Michael Massimino and a colleague rewired its electronics. The astronauts cheered when Mission Control announced the chemical analyzer, the Space Telescope Imaging Spectrograph, or STIS, had been revived.

The instrument studies objects such as the atmosphere of planets circling other stars.

On Saturday, another team of astronauts revived a Hubble camera that broke two years ago. The mission is "an astounding victory for science," said NASA scientist Jennifer Wiseman. "The telescope has more capabilities now than it ever has before."

Never before have astronauts tried to repair Hubble's scientific instruments. Those instruments weren't designed for maintenance, so working on them poses major challenges to astronauts wearing stiff, thick space gloves.

Sunday's outing was the fourth of five spacewalks planned for the crew of Atlantis. The shuttle is paying the last service call to the storied, 19-year-old telescope, credited with solving some of the universe's greatest mysteries — including estimating the age of the universe at 12 billion to 14 billion years. The seven Atlantis astronauts want to rejuvenate the Hubble to ensure it will last at least another five years.

The astronauts encountered multiple problems Sunday. First, Massimino couldn't undo a bolt on a handrail, which blocked access to the failed spectrograph. Massimino finally yanked the handrail free after Mission Control gave the OK.

Then Massimino had trouble installing a device designed to grab 100-plus tiny screws he had to take out. The device was supposed to sit on the door of the spectrograph and keep the screws from floating into the Hubble's workings.

Finally Massimino's power screwdriver went dead, leading the exasperated astronaut to blurt out, "Oh, for Pete's sake!" He had to stop work and travel to a distant tool box to get a spare screwdriver.