Subject: Administrative: NOAA-18 ENHANCED GYE FLIGHT SOFTWARE TEST, Issued: February 13, 2012 1340 UTC
Topic: NOAA-18 Enhanced GYE Flight Software On-Orbit Test
Date/Time (UTC) Message Issued: February 13 2012, 13:40:00 UTC
Satellite(s) Involved: NOAA-18
Instrument(s) Involved: All Instruments
Product(s) Involved/Affected: All data and products from NOAA-18
Date/Time(UTC) of Initial Implementation: February 21, 2012, 15:03:40 UTC
Date/Time(UTC) of Expected End: February 23, 2012, 22:59:40 UTC
Length of Outage: 56 hours
Details/Specifics of Change:
From 21 February 2012 (JDAY 052) at 15:03:40 UTC (orbit 34811) to 23 February 2012 (JDAY 054) at 22:59:40 UTC (orbit 34844), NOAA-18 will be placed for an enhanced GYE flight software on-orbit test. The test consists of four parts:
2 orbits of reduced gyro testing due to a software location change, from 15:03:40 UTC (orbit 34811 through 34813) on February 21.
24 hours of gyroless testing, from February 21, 2012, 18:09:10 UTC (orbit 34813) to February 22, 2012, 17:58:30 UTC (orbit 34827), with yaw updates allowed from the sun sensor.
24 hours of gyroless testing, from February 22, 2012, 17:58:30 UTC (orbit 34827) to February 23, 2012, 17:48:00 UTC (orbit 34841) without yaw updates from the sun sensor.
A recovery with 3 orbits (34841 through 34844, 17:48:00 through 22:59:40 UTC) to verify that the spacecraft is back in nominal mode ACS control and performing as expected.
During the test period, NOAA-18 instrument L1b data may have geolocation errors out of SPEC. In general, the geolocation accuracy of NOAA-18 L1b data is expected to be close to that of the operational NOAA-15, which has been operated in an enhanced reduced gyro mode since 2011-143. The biggest/sharpest geolocation errors may occur for the second test period, from February 21, 2012, 18:09:10 UTC (orbit 34813) to February 22, 2012, 17:58:30 UTC (orbit 34827). There may be once per orbit GYE yaw disturbances, which are expected to happen in a very short time period and to trigger geolocation errors up to a level of 20 to 25 km. However, the regions with that geolocation error are expected to be narrow. In addition, the big geolocation errors will mainly be observed near the two edges of scans and near the South Pole.
The NOAA-18 instrument L1b data will be distributed throughout the test period, since the data will be useable for many users. At the start of test two, users can expect a latency increase by up to 2 orbits. For those users who have a strict geolocation accuracy need, they may want to block the data usage during the test period, from February 21, 2012, 15:03:40 (orbit 34811) UTC to February 23, 2012, 22:59:40 (orbit 34844) UTC.
Contact Person(s) Name/Email/Phone Number for Questions:
ESPC Operations at ESPCOperations@noaa.gov at 301-817-3880
Carl Gliniak at email@example.com at 301-817-4207
Dejiang Han at firstname.lastname@example.org at 301-817-4119
Web Site(s) for applicable information: N/A