ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Wednesday, February 28, 1996 TAG: 9602280082
SECTION: NATIONAL/INTERNATIONAL PAGE: A-1 EDITION: METRO
DATELINE: CAPE CANAVERAL, FLA.
SOURCE: Associated Press
The plot thickened Tuesday: NASA managed to communicate with the escaped satellite-on-a-cord and discovered it had a dead computer and an empty gas tank.
``There has been an event on the satellite that we do not understand yet,'' Mission Control told the astronauts aboard space shuttle Columbia.
NASA officials said they were uncertain whether the satellite problems had anything to do with Sunday night's break in the 14-mile cord. They also did not know whether these problems would have occurred if the satellite had remained attached to Columbia.
All data indicated the satellite was fine when it broke loose and for at least 30 minutes afterward. Stray voltage or circuitry trouble may have caused the satellite systems to malfunction, NASA said.
``It's a very interesting puzzle,'' said NASA's Anthony Lavoie, chief engineer for the satellite. ``We don't have all the answers right now.''
Engineers at Johnson Space Center in Houston sent radio commands to the satellite as it soared overhead, hoping to find clues as to what caused the copper, nylon and Teflon cord to snap.
NASA was surprised to find that one of the main computers and a gyroscope were not working and that valves on both nitrogen-gas thrusters were open. All 100 pounds of gas had spewed out.
Controllers later managed to turn on that gyroscope and closed all thruster valves on the wobbly craft, which was dragging 12.2 miles of cord. They also activated all four science instruments on the satellite to monitor surrounding electrical and magnetic fields as well as the motion of the satellite and its tether.
The fact that it's working at all is ``extraordinary despite all that it's been through,'' said astronaut Jeffrey Hoffman.
The half-ton satellite - the heart of a $400 million-plus experiment to generate electricity in orbit - has enough battery power to allow communication for another one or two days.
After that, it will be an expensive piece of space junk.
NASA said it is too perilous to send the shuttle after the satellite. The dangling cord could wrap itself around the spaceship, endangering the astronauts.
Since the accident, NASA officials have refused to speculate on the cause of the tether break, despite astronauts' observation that the frayed end of the cord remaining on Columbia looked charred and melted.
Some scientists said the 3,500 volts of electricity the Italian satellite was generating could have caused a spark or discharge that could have severed the U.S.-built tether.
Lavoie said it's unlikely the satellite could have caused the tether to break, even with all its problems.
The satellite trailed Columbia by thousands of miles Tuesday in an orbit nearly 50 miles higher. Columbia will pass within 70 miles of the satellite Friday, eight days into their 14-day flight.
NASA expects the satellite to re-enter the atmosphere and burn up in three to four weeks. Officials said the satellite and white tether will be visible to the naked eye at times from the southernmost parts of the United States, as early-morning sunlight reflects off the long conglomeration.
``Obviously, we would have preferred people not get a chance to see this, but we have a satellite up there now with 20 kilometers of tether on it,'' Hoffman said. ``It should be an absolutely awesome sight.''
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``We have a satellite up there now with 20 kilometers of tether on it. It should be an absolutely awesome sight.''
Jeffrey Hoffman
Space shuttle crew member
we have a satellite up there now with 20 kilometers of tether on it,'' Hoffman said. ``It should be an absolutely awesome sight.''astronaut Jeffrey Hoffman.
LENGTH: Medium: 80 lines ILLUSTRATION: GRAPHIC: AP. 1. The tether. 2. Breaking away. color.by CNB