Opportunity's systems declared healthy, as Spirit lives on

By Blaine P. Friedlander Jr.

A view to the west-southwest of Opportunity shows part of the crater in which it rests. This is the darkest landing site ever visited by a spacecraft on Mars, but this image has been lightened somewhat for the Web. The rim of the crater is approximately 10 meters (32 feet) from the rover. The crater is estimated to be 20 meters (65 feet) in diameter. Scientists are intrigued by the abundance of rock outcrops dispersed throughout the crater, as well as the crater's soil, which appears to be a mixture of coarse gray grains and fine reddish grains. NASA/JPL/Cornell Click on the image for a high-resolution version (Very large! 7838 x 2915 pixels, 14.5MB)

PASADENA, Calif. -- NASA engineers at the Jet Propulsion Laboratory today (Jan. 26) declared that the Mars rover Opportunity's systems are in perfect running order. Even one of its five scientific instruments, the Mössbauer spectrometer, which had problems during its journey from Earth, is working well, Cornell University's Steven Squyres, leader of the mission science team, said at a press conference.

Opportunity returned stunning panoramic images that showed a wealth of detail of the crater in Meridiani Planum, where the craft bounced down at 12:05 a.m. Eastern time Jan. 25. "This is geologists gone wild," quipped a delighted Squyres, Cornell professor of astronomy.

Meanwhile, NASA engineers produced a new diagnosis of what ails Spirit, Opportunity's twin rover which has been on Mars since Jan. 3. On Jan. 21 a routine command for the operation of the elevation motor on Spirit's was ignored and the rover began spewing garbled data and refusing to conserve energy or to put itself into sleep mode.

Jim Bell, right, Cornell associate professor of astronomy and leader of rhe Pancam team for both Mars rovers, happily describes the first panoramic color image from Opportunity at a NASA press conference in Pasadena Jan. 26. Fellow Cornell professor Steve Squyres, lead scientist for the rovers' science packages, looks on. Cornell News Service photo by Blaine Friedlander Jr. Copyright © Cornell University Click on the image for a high-resolution version (2048 x 1536 pixels, 557K)

Mission engineers said that Spirit's onboard computer system had tried more than 60 times to re-boot -- or reset.

After days of theorizing as to the cause, engineers today produced a seemingly simple diagnosis: computer files left over from the "cruise phase" of the mission (i.e. the journey from Earth to Mars orbit) had not been deleted from the rover's flash memory and were taking up valuable space, sending Spirit into revolt. In fact, Spirit dated its readable transmission information as the year 2053. "There are not a lot of scenarios that put us in 2053," said Jennifer Trosper, mission manager at JPL.

Previously, mission engineers had thought that a solar storm might have caused the glitch. On Jan. 21, one of the instruments on the NASA Mars Odyssey satellite orbiting the red planet detected an ion or neutron storm that apparently originated from the sun. The Russian-built High Energy Neutron Detector, or HEND, on Odyssey, reported that Mars might have been besieged by a solar storm, and the storm could be a suspect in causing the software to act strangely.

However, engineers began to discount the theory as when they noticed that the timing of the storm and the computer glitch did not seem to match. Trosper, however, said the storm could still be contributing factor.

On Jan. 24 engineers discovered that Spirit's flash memory, the same kind of memory used in digital cameras, had been disrupted. The flash memory is one of three kinds of memory used by the rovers to send and receive data: a random-access memory, or RAM; an electrically erasable, programmable read-only memory, or EEPROM, which allows large amounts of data to be stored and retrieved; and the flash memory, which retains data without the need for power. The rovers' software and those spectacular images are stored in the EEPROM.

Spirit's computer runs on a modified microprocessor, a 32-bit Rad 6000, a radiation-hardened version of a PowerPC chip commonly found in Macintosh computers, operating at a speed of 20 million instructions per second.

The RAM is 128 megabytes, while the flash and the EEPROM combine for 256 megabytes. The rovers' wing-shaped solar panels daily recharge the lithium-ion battery system that provides 140 watts -- or about two light bulbs' worth -- of power.

JPL engineers and software experts are now temporarily working around the problem flash memory, allowing the rover to gather power and retain its ability to keep its temperature-sensitive instruments warm.

Trosper said that Spirit is now in "rehab" and that the cruise-phase files will be deleted. She suggested that JPL engineers also delete the cruise-phase files in Opportunity's flash memory.

Yesterday (Jan. 25), for the first time in days, Pete Theisinger, NASA rover project manager, showed evidence of a smile when discussing Spirit. "We are on our way to normal recovery," he said. "And we have a very good chance of having a very good rover."

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