Topic: S-NPP Star Tracker Lunar Intrusion Test scheduled for April 11, 2016
Date/Time Issued: April 7, 2016 1430Z
Product(s) or Data Impacted: No impact expected
Date/Time of Initial Impact: April 11, 2016 18:18:44Z
Date/Time of Expected End: April 11, 2016 18:30:02Z
Length of Outage: N/A
Details/Specifics of Change: On Monday April 11, the S-NPP satellite
will be commanded to ignore Star Tracker inputs from the on-board
Attitude Determination & Control System (ADCS) from 18:18:44 Z to
18:30:02 Z. S-NPP has been experiencing larger than expected attitude
errors when the Moon intrudes the Star Tracker Field-Of-View (FOV),
potentially due to poorly identified stars. Removing the Star Tracker
inputs from the ADCS will prevent inclusion of any poorly identified
stars in the attitude solution, and the ADCS will use Gyro data only
for attitude estimation during this period. No data impacts are
expected and those data should continue to meet specification during
that short test event, however, there is a potential for slightly
degraded attitude that may affect all observations towards the end of
this period.
Contact Information for Further Information: ESPC Operations at
ESPCOperations@noaa.gov at 301-817-3880