Endeavour's astronauts had trouble pointing the ultraviolet telescopes aboard the space shuttle Friday, just two days into their two-week astronomy mission.
"Boy, the (pointing system) is drifting all over the place," astronaut Ronald Parise grumbled.Parise and Samuel Durrance, both astrophysicists, had to manually point one of the three telescopes, which are supposed to lock automatically on their targets via computer. The two scientists had to do the same thing in 1990 on the first, problem-plagued flight of the telescopes, which are called Astro.
The astronauts had to skip some stars Friday because of the pointing trouble. By evening, ground controllers had resolved most of that problem by having the crew change its procedures, said NASA's Dave Jacobson, chief engineer for the mission.
Charles Meegan, a NASA scientist on the ground, said there will be plenty of time to go back and focus on the lost targets: The 151/2-day mission is the longest shuttle flight planned by NASA.
Among the more than 600 possible targets are galaxies, quasars, the moon, Jupiter and Io, one of Jupiter's moons. Astronomers hope to observe a volcanic eruption on Io on Saturday.
As of Friday afternoon, the telescopes had focused - more or less - on several stars, as well as a remnant of an exploded star 1,500 light years away.
None of that was very useful to Arthur Davidsen, an astrophysicist at Johns Hopkins University. He is in charge of the telescope that needed manual pointing.
"We're not satisfied with what we've got so far," Davidsen said. "We're having some difficulty getting stable and precise pointing. But I think this can be overcome. This is very early still. I'm not worried - yet."
The two other telescopes have small mirrors that can be moved quickly via computer command to compensate for the drift, but Parise couldn't do that fast enough in at least one case.
NASA spent $45 million to improve the pointing system and the telescopes after that first troubled flight. The telescopes cost $150 million back in 1990.
The problem this time didn't appear to be as severe, mission manager Robert Jayroe said. And it didn't seem to be slowing the astronauts down as much.
"We had so much practice on Astro-1 with that we got real good at it," Jayroe said.
Four of Endeavour's seven astronauts are operating the telescopes. They're working in two shifts around the clock.