NOAA-15 HIRS and AVHRR Update - July 21

NOAA-15 Update - July 21, 2000


On Monday, July 24, a test will be conducted with the NOAA-15 HIRS. At
12:38Z, the HIRS filter wheel housing heater will be turned on for a
duration of 48 hours. It is hoped that the filter wheel elevated temperature
will draw additional lubricant into the bearing assembly. Product impacts
should be expected for the first 12 hours or so after the heater turn-on as
the filter wheel reaches a new steady-state operating temperature.

In addition, an on-board command macro is being validated for upload to
NOAA-15 early in the week. This command macro, which is loaded directly to
flight software, is designed to automatically trigger off elevated HIRS
filter wheel current values (280 mA threshold) to command the filter wheel
into High Power mode, thereby supplying 35% more current to the filter wheel
motor. This action duplicates the current operational procedure during a
pass, but extends the capability to 100% of the orbit.


On Thursday, July 27, the recorders will be configured for one day to record
continuous AIP data along with GAC. The AIP data, which contains all
spacecraft and instrument data aside from the AVHRR, is recorded independent
of the MIRP. This operational test will be used to compare data quality
between the two streams to help evaluate MIRP/AVHRR impacts to other
instrument data. The prime impact to the users due to this test is the loss
of one day of LAC recordings from NOAA-15.

If you have any questions or concerns please contact me.


Cecil A. Paris
Calibration Physical Scientist
Phone 301-457-5247
Fax 301-457-5199