PASADENA, Calif. --A flash-memory chip snafu has been cited as the apparent cause for crippling the Spirit Mars Exploration Rover, according to the Space.com Web site on Sunday (January 25, 2004).
Last Wednesday (January 21, 2004), officials at NASA's Jet Propulsion Laboratory (JPL) discovered "a serious anomaly" with the robot Spirit, which landed on Mars several days ago. The problem stopped the data transmissions of the robot for almost 24 hours. But now, the unit is rebooting over and over again in an attempt to restore itself.
Officials from JPL now believe the problem involves the robot's flash memory and associated software, according to the Web site. Spirit's flash memory is mostly used for the storage and retrieval of engineering and scientific data, although the report did not elaborate on the details.
"Engineers found a way to stop Spirit's computer from resetting itself about once an hour by putting the spacecraft into a mode that avoids use of flash memory," according to a statement released by NASA today (January 26, 2004). "One of the next steps planned is to erase from flash memory the files stored there from the spacecraft's cruise to Mars from Earth. That is intended to lessen the task of managing the flash memory files."
Restoration efforts continue making progress on Spirit. "We have a patient in rehab, and we're nursing her back to health," said JPL's Jennifer Trosper, mission manager, in a statement from NASA on Monday.
Officials from NASA did not elaborate on the flash-memory problems. The two Mars rovers consist of a single board computer called the RAD6000, which is reportedly built by BAE Systems in Manassas, Va. The microprocessor on the system is an older, 25-MHz part, based on IBM Corp.'s PowerPC family. It is a radiation-hardened device.
The RAD6000 does not use a hard drive for storage. Instead, data are kept in 128-MB of random access memory, although it's unclear which vendor supplies those parts. The computer runs a real-time operating system from Wind River Systems Inc.
Others are also providing chips for the Mars rovers. Intersil Corp. said that specially produced advanced semiconductor products it manufactures are incorporated in various electronic systems of the two Mars Exploration rovers.
Xilinx Inc. claims that its radiation tolerant FPGAs are playing a critical role in the mission. Xilinx' radiation-tolerant Virtex FPGAs are being used in the "main brain" of the rover vehicle, controlling the motors for the wheels, steering, arms, cameras and various instrumentation, enabling the vehicle to travel about the planet.
Xilinx radiation-tolerant XQVR4000XL devices are used to control the crucial pyrotechnic operations during the multi-phase descent and landing procedure for the Spirit Rover and will play a similar role in the Opportunity rover.
Meanwhile, on the bright side, NASA's second rover, Opportunity, is sending data of Mars surface to Earth. During the second day on Mars for NASA's Opportunity rover, key science instruments passed health tests and the rover made important steps in communicating directly with Earth, according to the U.S. agency.
On Earth this morning, the rover transmitted high-resolution color pictures of Mars. "We're looking out across a pretty spectacular landscape," said Jim Bell of Cornell University and lead scientist for the panoramic cameras on Spirit and Opportunity, in a statement "It's going to be a wonderful area for geologists to explore with the rover," he said in a statement from NASA.
Another major step planned for Opportunity's third day is to begin using its high-gain antenna for communicating directly with Earth at a high data rate, said Jackie Lyra of NASA's JPL.
So far, Opportunity has tested the three scientific sensing instruments on its robotic arm that will be used for up-close examination of rocks and soil: the microscopic imager, the alpha particle X-ray spectrometer for determining what elements are present, and a Moessbauer spectrometer for identifying iron-containing minerals, according to NASA.
"I'm pleased to report that all are in perfect health," said Steve Squyres of Cornell University and principal investigator for the science instruments on the rovers, in a statement.