[meteorite-list] Free Spirit: Third Extrication Drive Ends With Wheel Stall

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 23 Nov 2009 15:58:17 -0800 (PST)
Message-ID: <200911232358.nANNwInG021158_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2009-173

Free Spirit: Third Extrication Drive Ends With Wheel Stall
Jet Propulsion Laboratory
November 23, 2009

Spirit experienced a wheel stall with the right-rear wheel during the
second step of a two-step drive on Sol 2092 (Saturday, Nov. 21). This is
not the same wheel that stalled on Sol 1899 (May 6), the left-middle
wheel. On Sol 2092, the right-rear wheel did not experience a hard stall
like what was seen on Sol 1899. Instead, it stalled because the wheel's
progress fell behind the expected rotation rate. The rover had completed
about 4 meters (13 feet) of commanded wheel spin before the stall
terminated the drive. The center of the rover moved about 4 millimeters
(0.2 inch) forward, 3 millimeters (0.1 inch) to the left and about 3
millimeters (0.1 inch) down. The rover suspension stayed within the
tighter limits set for the drive, and there was only a fractional change
in rover tilt.

The plan ahead for today, Nov. 23, is to sequence a set of diagnostics
to explore the right rear wheel stall. The diagnostics will include a
rotor resistance test, a possible steering test, a small backward
rotation of just the right-rear wheel and a short (about 1 meter, or 3
feet) forward commanded motion of the rover. Resumption of the
extrication driving would be no sooner than Wednesday.

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
2009-173
Received on Mon 23 Nov 2009 06:58:17 PM PST