
                         Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: FRIDAY, August 27, 1993                   TAG: 9308270007
SECTION: NATIONAL/INTERNATIONAL                    PAGE: A4   EDITION: METRO 
SOURCE: Associated Press
DATELINE: PASADENA, CALIF.                                LENGTH: Short

MARS PROBE'S TROUBLE MAY BE BAD TRANSISTOR

A transistor blamed for a pre-launch breakdown on a weather satellite now lost in space may have caused the disappearance of Mars Observer, NASA said Thursday.

If that theory is correct, the agency's Jet Propulsion Laboratory said, the loss of communications with Mars Observer "would be a non-recoverable situation," meaning the $980 million mission is doomed.

NASA lost touch with both the Mars Observer and the $62 million NOAA-13 weather satellite on Saturday.

The transistors are crucial for operation of computer clocks on both spacecraft. Neither spacecraft can operate without the clocks, known as RXOs, or "redundant crystal oscillators."

NOAA-13's launch was delayed from June until this month, partly because its clock had failed and had to be replaced. An investigation blamed that breakdown on the failure of the same kind of transistor used in Mars Observer's two clocks, the National Aeronautics and Space Administration said in a statement.

The transistors, manufactured by Frequency Electronics, all came from the same lot, the agency said.

Some analysts suspect the missing-in-action Mars Observer was blown to bits before it ever went into orbit around Mars.

But NASA believes that's extremely unlikely. But with no word from the spacecraft, engineers cannot rule out the possibility that it sailed past Mars or was destroyed or damaged.

by CNB