astronauts work on hubble
© Associated Press/NASA TVIn this image from NASA TV astronauts Mike Good, left, and Mike Massimino work to upgrade the Hubble Space Telescope during a spacewalk, Friday, May 15, 2009
The struggle had NASA on edge for about two hours. The gyroscopes are needed to point the 19-year-old observatory, and getting them in was the top priority of the repair mission.

It was the second spacewalk in as many days for the Atlantis astronauts. On Thursday, another two-man team installed a powerful new camera and a computer data unit, after struggling with a stubborn bolt. NASA had hoped for an easier, less stressful spacewalk, but instead had to endure more drama.

Michael Massimino, who was working from inside Hubble, and his partner, Michael Good, had no problem removing all six of Hubble's 10-year-old gyroscopes. They easily plugged in the first new set of two gyroscopes, but despite repeated efforts, could not get the second set properly mounted.

Mission Control instructed them to go get the next box of gyroscopes to see if that one would fit. It did and the astronauts cheered.

But when the spacewalkers tried to tuck in the last set of gyroscopes, it wouldn't fit properly. Mission Control instructed the men to go get a spare box of gyroscopes from the shuttle, and put that one in. The spare is refurbished; it was returned from Hubble in 1999.

After repeated efforts, the astronauts managed to install the refurbished set, which one Hubble scientist said was almost as good as the brand new ones. By then, however, five hours of the spacewalk had passed and the spacewalkers had yet to start on the other major chore of the day.

But the gyroscopes were the No. 1 task. Three of the old gyroscopes no longer worked, and two others had been acting up. The other had seen a lot of use.

"My friend Leonidas has a couple of words for you guys that are appropriate right now," shuttle commander Scott Altman told the spacewalkers, referring to the Spartan king who died in battle in 480 B.C. "Remember this day, men, for it will be yours for all time." Then Altman laughed.