Bad Memories: Mars Rover Suffers More Amnesia Events
Although engineers identified the problem and applied a software fix for Opportunity's amnesia events, the aging NASA mars rover has again been afflicted with further memory issues.
Although engineers identified the problem and applied a software fix for Opportunity's "amnesia events," the aging NASA mars rover has again been afflicted with further memory issues.
"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, Calif., in a news release "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."
The problem was thought to be centered around one of the seven memory banks in Opportunity's flash memory - the rover's on board "hard drive" of sorts, where data can be stored even if the rover is powered down. Rather than being lost, mission telemetry can be stored when the rover is switched off to preserve battery life during the Martian nights.
But late last year, the rover would "forget" valuable data, caused by a corrupt flash data bank. As a consequence, random resets would occur throughout the day. This was hindering the mission's progress, prompting mission engineers to adopt a "no-flash mode" where Opportunity would avoid use of its flash memory, instead temporarily storing data to its volatile memory and regularly transmitting the data back to Earth before downtime.
Like the RAM on your PC or Mac, the volatile memory only provides temporary storage of data, becoming wiped when the rover powers down.
After uploading new software to avoid the use of the 7th flash memory bank, on March 20, engineers reformatted Opportunity's memory. Although the rover isn't currently exhibiting some of the worst symptoms associated with the amnesia, it appears that its memory problems are far from over.
NASA's Mars Exploration Rover Opportunity has extended its robotic arm for studying a light-toned rock target called "Athens" in this March 25, 2015, image from the rover's front hazard avoidance camera.
On Jan. 24, 2004, Mars Exploration Rover Opportunity (MER-B) entered the Martian atmosphere and bounced onto the red planet's surface. The complex stages of entry, descent and landing operation saw the rover, surrounded with airbags, roll into a small hollow called Eagle Crater in Meridiani Planum -- a feat rover mission scientists called a "hole in one." After righting itself, the airbags were deflated and pulled into Opportunity's lander so the golf cart sized robot could see Mars for the first time -- it's new home. The rover's primary mission was planned to last just 3 months; little did NASA realize that they would still have an operational rover exploring Mars
12 years later
. Here are just a few of the breathtaking views from Opportunity during the very early days of the mission.
Shown here is the first self portrait Opportunity beamed back to Earth shortly after landing on "Sol 0" of the mission (a sol is a Martian day and the length of any Mars surface mission is measured in sols). Its shiny solar array glints in the sunlight on top of its landing platform. Note the deflated airbags surrounding the rover and the rippled impressions the airbag made in the Mars dust.
Opportunity was the second of the twin Mars Exploration Rovers to touch down on Mars regolith in January 2004. A little over 2 weeks earlier, NASA had celebrated the successful landing of Spirit on the other side of the planet in Gusev Crater. Spirit was also highly successful, carrying out groundbreaking science in a very different landscape compared with Opportunity. Sadly, Spirit succumbed to the Martian elements in 2009 after becoming stuck in a sand trap.
In this section of a panorama captured by Opportunity's Pancam, the rover checks out its surroundings on Jan. 26, 2004. Eagle Crater's rim is approximately 10 meters from the rover, obsecuring Opportunity's view of the surrounding landscape.
This Jan. 30 view from Opportunity's rear Hazcam shows the deck of its lander and the surrounding crater before the rover "egressed" onto the Mars soil.
Evidence of the rover's dramatic entry surround the lander. These bounce marks look like they were created by a huge basketball, but they are actually imprints left by the huge airbags that were used to cushion Opportunity's landing, bounce and roll into Eagle Crater.
On Sol 7 of the mission (Jan. 31, 2004) rover drivers commanded Opportunity to roll onto the Martian surface, leaving behind the lander that it called home for the 283 million mile journey from Earth to Meridiani Planum.
The lander -- shown here in color with rover tracks in the background from Opportunity's egress -- was named the Challenger Memorial Station in memory of the final crew of the Space Shuttle Challenger who died when the shuttle suffered an in-flight breakup during launch on Jan. 28, 1986.
After exploring its little 22 meter-wide divot, Opportunity left Eagle Crater and took this panorama of its landing spot on the 33rd, 35th, and 36th sols of its mission. Surrounding the crater is the flat plains of Meridiani Planum, a region it would go on to spend 10 years and nearly 24 miles of hard roving (to date).
As the rover trundled over the loose regolith, rover drivers were able to use the wheels to carve out trenches in the dirt to see what materials lied beneath. Shown here is a trench that was opened for closer inspection by Opportunity's microscopic imager.
With the microscopic imager, Opportunity discovered the region it was exploring is littered in
. This surprise discovery has led scientists over the last decade to theorize that these spherical hematite inclusions originated from Mars' wet past or were formed through volcanic activity.
To analyze the material just below Mars rocks' surfaces, it employs the use of its rock abrasion tool that leaves a circular "lovebite" in rocks after use. This image by Opportunity's front hazcam shows one of those marks on a rock called "McKittrick," located in the "El Capitan" area of the larger outcrop near Opportunity's landing site on Sol 30 of the mission.
During exploration of Eagle Crater, Opportunity was able to spot its discarded backshell and parachute from its descent through the Martian atmosphere. This became a mission target for Opportunity to roll to and investigate.
In a rare opportunity to see a piece of the equipment that allowed the surface mission to survive the fiery entry into the Martian atmosphere a year after landing, Opportunity approached its old backshell that it last saw on Jan. 24, 2004, just before it touched down in Eagle Crater. Shown here is the shiny backshell from its heat shield that protected the rover from temperatures that soured to thousands of degrees on entry.
When Opportunity made its inspections of the heat shield debris field, engineers were excited to see that the shield had inverted, exposing the silvery inner material. Notice the large springs on the ground -- very man made objects in a very alien landscape.
In the months after landing, it became clear that Opportunity wasn't going to stop operating and its mission was extended far beyond its original 3 months. Throughout its adventures, Opportunity repeatedly took "selfies" so that engineers back on Earth could monitor dust buildup on its solar panels. Around a year and a half into the mission, the panels are seen to be virtually dust free. This, however, is not how Opportunity's solar array remained...
A decade of Mars roving caused a huge amount of dust buildup on Opportunity's solar panels. In this photograph taken in January 2014, Opportunity is almost camouflaged. Although this inevitably reduced the amount of sunlight that can be turned into energy, the rover soldiered on -- until it was given a helping hand by Mars winds and dust devil "cleaning event," blowing some of that dust clear...
This self-portrait of NASA's Mars Exploration Rover Opportunity was taken in late March 2014 (right) showing that much of the dust on the rover's solar arrays was removed since a similar portrait from January 2014 (left). A decade of Mars exploration has taken its toll -- one of the rover's six wheels has frozen up and some of its instruments are kaput -- but Opportunity rolls on, turning up valuable new science and finding new mysteries that provide answers to some of the most vexing questions in planetary science. But above all, Opportunity is a testament to the scientists and engineers at NASA and collaborating institutions who sure know how to build a rover.