[meteorite-list] Opportunity Rover Amnesia Event Follows Latest Memory Reformatting

[Ron Baalke]

http://www.jpl.nasa.gov/news/news.php?feature=4528

Rover Amnesia Event Follows Latest Memory Reformatting
Jet Propulsion Laboratory
March 27, 2015

Mars Exploration Rover Mission Status Report

The team operating NASA's Mars Exploration Rover Opportunity learned Thursday 
that the long-lived rover experienced a brief amnesia event related to 
its flash memory, the first since a reformatting of that nonvolatile type 
of memory a week earlier.

The amnesia event did not result in any loss of science data, and Opportunity 
subsequently continued its activities using tools on its robotic arm to 
examine a rock target called "Athens." The rover experienced dozens of 
similar amnesia events and more serious flash-related resets of the onboard 
computer prior to 2015, then operated without using flash memory until 
last week.

"We changed how the rover uses flash memory in an attempt to correct problems 
the rover had been experiencing," said John Callas, project manager for 
Opportunity at NASA's Jet Propulsion Laboratory, Pasadena, California. 
"Although we are a little disappointed at the occurrence of an amnesia 
event only five days after reformatting, we are not surprised. There is 
still no clear understanding of what is causing the problems. Only time 
will tell if we have been successful in mitigating the most serious flash 
problems."

Use of flash memory enables the retention of stored data when power is 
turned off. Opportunity is powered down every night to conserve energy 
generated by its solar panels. The rover also has volatile memory, which 
can store data while powered. For three months until last week, the team 
operated the rover in a mode that avoided use of flash. Instead, the rover 
stored science data in volatile memory for downloading to Earth each day 
before shutting down for the night.

Opportunity has seven banks of flash memory. This month, the team revised 
the rover's onboard software to avoid use of Bank 7, where some of the 
earlier problems with flash memory had been traced. After the March 20 
reformatting, the rover resumed use of the other six banks. No root cause 
for the full combination of flash problems has been determined, since 
many of the past problems with flash could not be traced to a specific 
bank.

Before switching to the no-flash mode in December, Opportunity was experiencing 
multiple resets daily. The rover has experienced no resets so far in the 
first week after resuming the use of flash, so the remedy actions appear 
to have addressed the most serious flash problems, at least for now.

Earlier this week, Opportunity became the first vehicle ever to travel 
the distance of a marathon race on the surface of another world. The rover 
is examining outcrops on the western rim of Endeavour Crater, approaching 
"Marathon Valley," where clay minerals have been detected in observations 
by NASA's Mars Reconnaissance Orbiter.

NASA's Mars Exploration Rover Project landed twin rovers Spirit and Opportunity 
on Mars in early 2004 to begin missions planned to last only three months. 
Both rovers far exceeded those original plans. Spirit worked for six years, 
and Opportunity is still active. Findings about ancient wet environments 
on Mars have come from both rovers. The project is one element of NASA's 
ongoing and future Mars missions preparing for a human mission to the 
planet in the 2030s. JPL, a division of the California Institute of Technology, 
manages the project for NASA's Science Mission Directorate in Washington.

For more information about Opportunity, visit:

http://www.nasa.gov/rovers

and

http://marsrovers.jpl.nasa.gov

Follow the project on social media at:

http://twitter.com/MarsRovers

http://www.facebook.com/mars.rovers

Media Contact
Guy Webster
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6278
guy.webster at jpl.nasa.gov

2015-102