Phoenix Lander digging with stressed out memory

William Atkins
Thursday, 19 June 2008 19:26

Science - Space

NASA mission managers had some problems on Tuesday, June 17, 2008, with the Lander’s non-volatile flash memory, had it take the day off on Wednesday, and are telling it to do activities on Thursday that doesn't require its memory.

Late on Tuesday (Martian Day 21, Sol 21), Phoenix relayed back to Earth the same piece of data over 45,000 times. T

Needless to say, that generated quite a bit of interest as NASA scientists tried to figure out what was going wrong.

Mission scientist Ray Arvidson (Washington University, St. Louis, Missouri) stated, "It's unfortunate to lose any bit of science. But it's not really critical stuff that you kick yourself over." [Associated Press: “Mars lander loses day of work after data glitch”]

This type of data is usually stored in the Lander’s flash memory and used to maintain its computer files. Normally, important science data is also stored in the flash memory overnight and then uplinked to two orbiting spacecraft the next day.

However, so much of this maintenance data was inadvertently put into flash memory that the science data didn’t have enough room—so was never stored.

The science data was classified as non-high-priority because almost all of it can be recreated. However, some images taken of the robotic arm of Phoenix as it dug into the surface of the northern arctic region of Mars cannot be redone.

Phoenix project manager Barry Goldstein (NASA Jet Propulsion Laboratory) stated, “The spacecraft is healthy and fully commandable, but we are proceeding cautiously until we understand the root cause of this event," [University of Arizona: “NASA Mars Lander to Dig; Team Probes Flash Memory”]

While mission managers analyze the problem, they commanded the Phoenix to not perform any science activities on Wednesday (Sol 22) and to reduce the amount of maintenance data that goes into its flash memory.

Goldstein stated, “We can continue doing science that does not rely on non-volatile memory. Most science data collected during the mission has been downlinked to Earth on the same sol it has been collected, not requiring overnight storage, but on some sols the team has intentionally included imaging that yields more data than can fit in the afternoon communication passes. This has been done in order to take advantage of the capacity to downlink additional data during communications passes on the following Martian mornings."

He added, "In the short term, while the root cause of the unexpected amount of housekeeping data is being determined, the science team will forgo that strategy of storing data overnight." [University of Arizona]

What's on the agenda for Phonix on Thursday? Please read on.