QUOTE (Cassini Event log)
Cassini's magnetometer team has concluded that a leak in a helium lamp in one of two detectors on the magnetometer caused the loss of one of the detectors--the vector scalar helium detector-- after nearly nine years of flawless operations. This detector is comprised of multiple electronic components and one helium lamp. The detector has not been operational since Nov. 2005, in spite of tests to turn the instrument off and then back on at increasing time intervals.
The second detector continues to function at full capacity.
The magnetometer operated flawlessly throughout pre-flight testing, Earth swing-by, cruise from Jupiter to Saturn, and the first year and one-half in Saturn orbit. However, a gradual degradation that began a year or more before Saturn orbit insertion in 2003 had been evident in two housekeeping and engineering telemetry parameters that monitor the output signals from the sensor.
The second detector continues to function at full capacity.
The magnetometer operated flawlessly throughout pre-flight testing, Earth swing-by, cruise from Jupiter to Saturn, and the first year and one-half in Saturn orbit. However, a gradual degradation that began a year or more before Saturn orbit insertion in 2003 had been evident in two housekeeping and engineering telemetry parameters that monitor the output signals from the sensor.
Nine years before the first subsystem loss! It is also worth noting that they were monitoring at least two parameters that more-or-less predicted the eventual malfunction. What great design and engineering teams!
