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

DATE: MONDAY, January 10, 1994                   TAG: 9401100082
SECTION: NATIONAL/INTERNATIONAL                    PAGE: C-4   EDITION: METRO 
SOURCE: The Washington Post
DATELINE: WASHINGTON                                LENGTH: Medium

SMALL FIX MAKES BIG PROBLEM?

Seven months before the launch of NASA's Mars Observer, managers made a change in the flight plan that might have caused the $500 million spacecraft to vanish on Aug. 21, according to sources familiar with the program.

Instead of pressurizing the craft's propellant tanks five days after the launch, as originally planned, NASA managers decided to delay the procedure for 11 months - until the Observer reached the red planet. They did so, ironically, to avert a potentially serious leak, officials said.

But the valves had not been designed to operate under the altered conditions, the sources said, and the result was probably an even worse leak that caused a catastrophic rupture in a fuel line and spun the craft out of control.

That the change in plan was made did not come up during a press briefing Wednesday at NASA headquarters, where an independent investigating panel reported its conclusions about what happened to the spacecraft and why.

Sources familiar with the program expressed surprise that mention of this management decision was omitted from the briefing and also from the report's executive summary and overview that were released to the press.

The change is described, however, in at least two places deep inside the report's 8-inch-thick, four-volume documentation, which was not released to the press but was available for review at NASA headquarters.

Timothy Coffey, chairman of the investigating board, was traveling and not available for comment, his office said. Others on the panel said they were not sure why the management decision to delay pressurizing the tanks was not mentioned.

The disappearance of the Observer is one of several embarrassments for NASA in recent years.

The decision to change the pressurization plan for the Mars probe was made in February 1992 because someone reminded the team that a similar propulsion system used on the Viking missions to Mars in the late 1970s had run into leakage problems when the fuel tanks were pressurized early in the flights, Glenn Cunningham, Mars Observer project manager at the Jet Propulsion Laboratory in Pasadena, confirmed last week.

As to why this concern developed so late in the program - after it was too late to make what would have been a simple mechanical fix and still meet the launch date - Cunningham said, "That's the sixty-four-dollar question."

by CNB