[meteorite-list] Phoenix Mars Lander to Dig; Team Probes Flash Memory

[Ron Baalke]

http://www.jpl.nasa.gov/news/phoenix/release.php?ArticleID=1750

NASA Mars Lander to Dig; Team Probes Flash Memory
Jet Propulsion Laboratory
June 18, 2008

TUCSON, Ariz. -- NASA's Phoenix Mars Mission generated an unusually high
volume of spacecraft housekeeping data on Tuesday causing the loss of
some non-critical science data. Phoenix engineers are analyzing why this
anomaly occurred. The science team is planning spacecraft activities for
Thursday that will not rely on Phoenix storing science data overnight
but will make use of multiple communication relays to gain extra data
quantity.

"The spacecraft is healthy and fully commandable, but we are proceeding
cautiously until we understand the root cause of this event," said
Phoenix Project Manager Barry Goldstein of NASA's Jet Propulsion
Laboratory.

Usually Phoenix generates a small amount of data daily about maintaining
its computer files, and this data gets a high priority in what gets
stored in the spacecraft's non-volatile flash memory. On Tuesday, the
quantity of this data was so high that it prevented science data from
being stored in flash memory, so the remaining science data onboard
Wednesday, when the spacecraft powered down for the Martian night after
completing its 22nd Martian day, or sol, since landing, was not
retained. None of that science data was high-priority data. Almost all
was imaging that can be retaken, with the exception of images taken of a
surface that Phoenix's arm dug into after the images were taken.

To avoid stressing Phoenix's capacity for storing data in flash memory
while powered off for overnight sleeps, the team commanded Phoenix
Tuesday evening to refrain from any new science investigations on
Wednesday and to lower the priority for the type of file-housekeeping
data that exceeded expected volume on Tuesday.

"We can continue doing science that does not rely on non-volatile
memory," Goldstein said. 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. 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.

Meanwhile, extra communication-relay opportunities have been added to
Thursday's schedule, so the science plan for the day will be able to
generate plentiful data without needing overnight storage.
Trench-digging, imaging and weather monitoring are in the plan.

The Phoenix mission is led by Peter Smith of the University of Arizona
with project management at JPL and development partnership at Lockheed
Martin, located in Denver. International contributions come from the
Canadian Space Agency; the University of Neuchatel, Switzerland; the
universities of Copenhagen and Aarhus, Denmark; Max Planck Institute,
Germany; and the Finnish Meteorological Institute. For more about
Phoenix, visit: http://www.nasa.gov/phoenix and
http://phoenix.lpl.arizona.edu.


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

Dwayne Brown 202-358-1726
NASA Headquarters, Washington
dwayne.c.brown at nasa.gov

Sara Hammond 520-626-1974
University of Arizona, Tucson
shammond at lpl.arizona.edu