[meteorite-list] Use of Curiosity Rover Arm Expected to Resume in a Few Days

[Ron Baalke]

http://www.jpl.nasa.gov/news/news.php?feature=4504

Use of Rover Arm Expected to Resume in a Few Days
Jet Propulsion Laboratory
March 6, 2015

Mission Status Report

Managers of NASA's Curiosity Mars rover mission expect to approve resumption 
of rover arm movements as early as next week while continuing analysis 
of what appears to be an intermittent short circuit in the drill.

A fluctuation in current on Feb. 27 triggered a fault-protection response 
that immediately halted action by the rover during the mission's 911th 
Martian day, or sol. Since then, the rover team has avoided driving Curiosity 
or moving the rover's arm, while engineers have focused on diagnostic 
tests. Science observations with instruments on the rover's mast have 
continued, along with environmental monitoring by its weather station.

"Diagnostic testing this week has been productive in narrowing the possible 
sources of the transient short circuit," said Curiosity Project Manager 
Jim Erickson of NASA's Jet Propulsion Laboratory, Pasadena, California. 
"The most likely cause is an intermittent short in the percussion mechanism 
of the drill. After further analysis to confirm that diagnosis, we will 
be analyzing how to adjust for that in future drilling."

The sample-collection drill on Curiosity's robotic arm uses both rotation 
and hammering, or percussion, to penetrate into Martian rocks and collect 
pulverized rock material for delivery to analytical instruments inside 
the rover.

The short on Sol 911 occurred while the rover was transferring rock-powder 
sample from the grooves of the drill into a mechanism that sieves and 
portions the powder. The percussion action was in use, to shake the powder 
loose from the drill.

Engineers received results Thursday, March 5, from a test on Curiosity 
that similarly used the drill's percussion action. During the third out 
of 180 up-and-down repeats of the action, an apparent short circuit occurred 
for less than one one-hundredth of a second. Though small and fleeting, 
it would have been enough to trigger the fault protection that was active 
on Sol 911 under the parameters that were in place then.

The rover team plans further testing to characterize the intermittent 
short before the arm is moved from its present position, in case the short 
does not appear when the orientation is different.

After those tests, the team expects to finish processing the sample powder 
that the arm currently holds and then to deliver portions of the sample 
to onboard laboratory instruments. Next, Curiosity will resume climbing 
Mount Sharp.

NASA's Mars Science Laboratory Project is using Curiosity to assess ancient 
habitable environments and major changes in Martian environmental conditions. 
JPL, a division of the California Institute of Technology in Pasadena, 
built the rover and manages the project for NASA's Science Mission Directorate 
in Washington. For more information about Curiosity, visit:

http://www.nasa.gov/msl

http://mars.jpl.nasa.gov/msl/

You can follow the mission on Facebook and Twitter at:

http://www.facebook.com/marscuriosity

http://www.twitter.com/marscuriosity

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

2015-081