Subject: PI: DMSP On-orbit Attitude Control Test for F-15: 12-13 June 2007 -
 Topic: DMSP On-orbit Attitude Control Test for F-15: 12-13 June 2007
Message Issued: June 7, 2007, 1815 UTC
Satellites Impacted: DMSP F-15
Products Impacted: All OLS and SSM/I products from DMSP F-15
Date/Time of Initial Impact: June 12, 2007  1124 UTC
--------------------------
Details:

1. On 12 and 13 June 2007, the DMSP program office and NOAA DMSP
Operations will conduct a 24-hour operational test of "gyro-less"
attitude control software on DMSP F15.  The purpose of the test is to
gather information and data about the performance of the gyro-less yaw
estimator (GYE) software and the spacecraft under its control, so that
improvements and modifications can be made prior to further failures of
the remaining gyro(s) on F15 or F16. 
   - Start of the test will be at 12/1124Z on Rev # 38748 
   - End of the test will be at 13/1615Z on Rev # 38765

2.  Ground testing of the software indicated the potential for
spacecraft pointing accuracy to become significantly degraded during
this operation. Aerospace Corp. simulation of the resulting impacts to
data quality, while under GYE control, indicate the earth-location
mapping errors for DMSP F15 imagery could be 90km or greater at edge of
scanned scene, causing the potential for significant degradation of
automated products using the OLS and SSM/I instruments. 

3.  AFWA will continue to ingest and transfer all F15 SIMPLE formatted
data to external users during the test (e.g., NGDC, FNMOC, Royal Navy
FWOC, National/Naval Ice Center, etc.) and post images on JAAWIN, with
caveats to users in the Hot News section.

4.  Users of direct readout data (RTD) from DMSP F15 should be aware of
the potential for mapping errors during this test.

5.  If any user chooses to randomly sample the imagery during the test
and perform a qualitative assessment of the magnitude of geolocation
errors noted, please provide that information to Mr Larry Pitsenbarger,
HQ AFWA/A5RS; email: larry.pitsenbarger@afwa.af.mil.  Those results
should be delivered within 48 hours of test completion (NLT COB 15 Jun 07).
 
6. There is no backup date for this test.

---------------------------
Contact Information:
Brian Hughes
Satellite Services Division
NOAA/NESDIS/OSDPD
301-763-8051 x106
Brian.Hughes@noaa.gov
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