Topic: SNPP Table 21 Upload planned for Tuesday September 20, 2016
Date/Time Issued: September 19, 2016 2246Z
Products or Data Impacted: None Expected
Date/Time of Initial Impact: September 20, 2016 1640Z
Date/Time of Expected End: September 22, 2016 1630Z
Length of Outage: See details below
Details/Specifics of Change:
On Tuesday September 20, 2016, an updated Command Block Memory (CBM) Table (Table 21) will be loaded to S-NPP with commands to patch Star Tracker software. The patch is to lower the Star Tracker Thermo-Electric Cooler (TEC) setpoint by 10 degrees Celcius in order to improve Star identification. During the upload of this CBM, the on-board CBM will be stopped, and will prevent some of ATMS Scan Reversals from running. Scan Reversals will be managed via ground command and may not coincide with nominal cadence, and some reversals may be missed.
On Wednesday September 21, 2016, Star Tracker #1 will be patched by from the CBM, followed by patching Star Tracker #2 on Thursday September 22, 2016.
Timeline of activities are as follows:
Tuesday September 20, 2016:
1639Z-1651Z SVL 25386: Upload CBM
1645Z: ATMS scan reversal will not be executed.
1650Z: Approximate time for manual ATMS scan reversal. Subject to miss reversal during this orbit.
1822Z-1833Z (SVL 25387): Backup upload opportunity. If CBM needs to be uploaded during this orbit, ATMS Scan Reversals will need to managed from ground for next two orbits, and the back orbit Scan Reversal will be missed for orbit 25387.
Wednesday September 21, 2016: Patch Star Tracker #1
14:36Z—14:50Z SVL 25399: Activate CBM Block for Star Tracker #1. No data impact expected.
Thursday September 22, 2016: Patch Star Tracker #2
1600Z—1613Z SVL 25414: Activate CBM Block for Star Tracker #2. No data impact expected.
Contact Information for Further Information: USMCC Operations usmcc@noaa.gov at
301-817-4576
Web Site(s) for applicable information: N/A