Originally created 07/14/97

Pathfinder's computer reprogrammed to avoid glitches



LOS ANGELES (AP) - NASA scientists trying to eliminate a software bug that briefly disconnected Pathfinder from Earth have reprogrammed the spacecraft's computer in hopes of avoiding a similar glitch.

The NASA team determined that a system overload caused the spacecraft's computer to reset last week, which left the team unable to communicate with the craft for a short time.

Over the weekend, the team reprogrammed Pathfinder to keep working if similar problems recur unless the problems persist. The change should prevent the team from losing contact with Pathfinder in the event of future overloads.

"What we've done is set a parameter (telling it) don't reset if you have problems, the first time," said Brian Muirhead, project manager at NASA's Jet Propulsion Laboratory in suburban Pasadena. "It's not a serious problem."

The software adjustment came as the Sojourner rover awaited another encounter with Yogi, the bear-shaped rock it got stuck on earlier in the week. Sojourner sat motionless over the weekend two feet from the rock it had unsuccessfully attempted to examine days before.

Sojourner was expected to sniff out the chemical composition of the rock by touching it with an instrument called an alpha proton X-ray spectrometer by sometime on Monday, Muirhead said.

Also this week, the team plans to study the planet's surface in hopes of finding out how Mars evolved and hoped to perform a Danish experiment testing the source of the magnetic dust that fills Mars' atmosphere.

"It collects the magnetic particles from the atmosphere and from that we can discern something about the particles. There's no place on Earth that is covered with magnetic dust," Muirhead said. "We should get an idea where that evolved from."