NOAA-17 detailed report

As most of you now know the NOAA-17 AVHRR has entered a state of severe
instability and high current drain. The nominal current level for this
instrument is at around 140ma. Currently NOAA-17 AVHRR scan motor has been
observed at over 271ma and is likely to climb. This condition is due to the
continued breakdown and contamination in the lubrication of the scan motor
bearings. In this state the condition will only get worse and as the current
continues to rise due to the added friction to the scan motor assembly, the
windings within the scan motor will begin to breakdown and the motor will
eventually stop working. NOAA engineers at this point have no other plans to
try and recover the instrument and expects that total failure to occur in
the near future.
Other spacecrafts like NOAA-14 have been observed to have the same type of
problems however the duration of each episode on NOAA-14 was much shorter
and the current had always returned to nominal values. The current on
NOAA-17 AVHRR scan motor since the anomaly occurred back in February of 2010
has always remained higher that nominal which gives reason to believe that
total failure is imminent. This is not to say that we could not be surprised
once more and the instrument will recover but the chances are very slim for
that to occur. Only an act of GOD can fix this now.
Once the AVHRR fails NOAA engineers most likely turn off the instrument or
commands the scan motor off as well as turning off the transmitter to the
HRPT and APT data stream. The remaining operational instruments onboard
NOAA-17 include AMSU-A2, AMSU-B (though degraded), HIRS, SARP, SARR, SBUV,
and SEM will continue to operate and be utilized until a severe anomaly
affects the power subsystem or attitude control which renders the spacecraft
For most of us users this comes at a bad time when NOAA plans to phase out
APT and HRPT and replace it with an incompatible system which at this time
has not been developed. The groundwork for future spacecraft is still under
review and we will not know for sometime what the future will hold for
weather satellite enthusiasts. One thing is for certain is that we must
continue to petition for a compatible system or one without an exuberant
cost to the user community. NOAA is working hard to serve the users and
maintain the current fleet, which will continue to provide data for at least
another 4 or more years. I look forward to continuing to provide information
to you and I am always available to answer any questions you might have. I
encourage all of you to reach out to the various user forums on yahoo and
throughout the internet as these folks are more than willing to provide you
with the most current information.

Thank you
Steven Ross

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