[meteorite-list] Further Tests Designed for Rover's Right-Rear Wheel

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 9 Dec 2009 13:42:40 -0800 (PST)
Message-ID: <200912092142.nB9LgeaF008777_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2009-185

Further Tests Designed for Rover's Right-Rear Wheel
Jet Propulsion Laboratory
December 07, 2009

A series of diagnostic tests on Spirit's right-rear wheel on sols 2104
and 2105 (Dec. 3 and 4) investigated stalls that occurred on Sol 2099
(Nov. 28) and earlier. The rover team cannot draw any conclusions at
this point, but the results are not encouraging, and further tests are
planned.

The recent tests included rotor-resistance tests at three temperatures
and a one-radian (about 57 degrees) forward motion test. The resistance
tests indicate anomalously high resistance in the motor winding at all
three temperatures. However, a curious transition from anomalously low
resistance to high resistance was observed very briefly on the very
first resistance test. The resistance remained high for the balance of
all the testing. Control measurements on the left-rear wheel showed
normal resistance for that actuator motor. For the forward wheel motion
test, the right-rear wheel stalled immediately and did not produce any
motion.

The plan ahead is to explore a set of hypotheses: possible motor
failure, possible internal gearbox jam, possible external jam (e.g., a
rock in the wheel). Commands being developed for Spirit's activities on
sols 2109 and 2110 (Tuesday and Wednesday, Dec. 8 and 9) will include
more diagnostics to explore these hypotheses.
Received on Wed 09 Dec 2009 04:42:40 PM PST