HOUSTON — A shuttle astronomer saw Halley's comet for the first time from orbit Monday but his view was spoiled by failure of an instrument designed to make the comet appear thousands of times brighter.
On the ground, National Aeronautics and Space Administration officials said they may shorten Columbia's much-delayed mission from five days to four. This would help NASA keep on its tight schedule of 15 shuttle missions this year.
Mission specialist George D. Nelson attempted to take unprecedented close-up pictures of Halley's comet using a camera attached to a light intensifier that would make the comet's faint light 10,000 times brighter, but discovered the device would not work.
The device had inadvertently been left operating in its packing case since late November or early December before it was stowed aboard Columbia. Nelson put fresh batteries in it but that did not help.
Instructions for Repair
Scientists said a repair procedure will be radioed up to the shuttle crewmen today to see if they can fix it with a wrench, a screwdriver and a Swiss army knife.
Mission Control instructed Nelson to remove the light intensifier from the 35-millimeter camera and take long exposures of the comet.
"Without the intensifier, the comet is pretty difficult to find in the window," Nelson told mission control. "I think we got it, and we got five different exposures on it. I'm not sure how bright they're going to be."
The comet is so close to the sun that it is in view from the shuttle only four minutes at a time.
On the following orbit Nelson used a spectrometer designed to help scientists identify the chemical makeup of the massive cloud of gases around the comet's icy nucleus, but he said he never saw the comet through that instrument.
"Maybe we got lucky," he said. "I don't know."
Alan Stern, the University of Colorado scientist in charge of the comet research, was more optimistic at an evening news conference. He said the observations were expected to produce some valuable results even without the image intensifier.
Stern said he did not think the failure was related to the fact that it had been left on. Instead, he said, the trouble appeared to be caused by a stuck safety device designed to keep it from looking at objects too bright. If that is the case, he said, the astronauts should be able to fix it by taking the unit apart and adjusting some screws.
May Land Thursday
Flight director Jay Greene said at a briefing Monday that he expected NASA to consider ending Columbia's flight a day early, on Thursday instead of Friday.
He said it is important to get Columbia back to the Kennedy Space Center in Florida to start preparing it for an astronomy mission scheduled for launch March 6. Columbia's launch for the current mission originally was scheduled for Dec. 18, but a record seven delays before its liftoff Sunday have created a squeeze on the March mission and on preparations for a Jan. 24 flight by shuttle Challenger.
The seven-member crew, which includes Rep. Bill Nelson, (D-Fla.), also spent much of the day conducting a variety of other experiments.
There were other troubles too. The crew reported malfunctions of a medical device, another astronomy instrument and a materials processing experiment. An auxiliary power unit fuel line also was getting too cold.