Topic: GOES-17 and GOES-15 Drift and Transition Plan

Date/Time Issued: October 22, 2018 1956 UTC

Product(s) or Data Impacted: All GOES-17 ABI, GLM, SUVI, SEISS, MAG, and EXIS products

Date/Time of Initial Impact: October 24, 2018 1345 UTC

Date/Time of Expected End: December 10, 2018 TBD UTC

Length of Event/Outage: See details below.

Details/Specifics of Change: This notification serves to update the start/end of GOES-15 drift and GVAR relay, update the final operating location of GOES-17, and provide other specific information.

Due to the Critical Weather Day declaration, GOES-15 will now begin drifting from its present location of 135 degrees west on October 29, 2018 at 2015 UTC until November 7, 2018 at 1900 UTC when GOES-15 reaches its new operating location of 128 degrees west. It will drift east at a rate of 0.88 degrees per day allowing all instruments and services to remain on with nominal GVAR and LRIT distribution. The GOES-15 GVAR M-Brelay through GOES-14 commenced on October 17, 2018 at 1500 UTC and will be available through both GOES-15 and GOES-14 satellites during the drift period. On November 13, 2018 at 1500 UTC, GOES-15 GVAR relay through GOES-14 will end while the GOES-15 GVAR direct broadcast still continues.

On October 24, 2018 at 1345 UTC, GRB, DCS, HRIT-EMWIN, and SARSAT will be disabled. Between 1345-1740 UTC, five of the six GOES-17 instruments (ABI, GLM, SUVI, SEISS, and EXIS) will be placed in safe or diagnostic modes. The MAG instrument will remain on during drift. M-BAfter 1740 UTC, GOES-17 will begin drifting from its present location of 89.5 degrees west at a rate of 2.5 degrees per day. It will complete drift on November 13, 2018 when it reaches its final operational location of 137.2 degrees west. The change from 137.1 to 137.2 degrees west has been made for operational efficiency to minimize impacts with other geostationary satellites. M-B

During the drift period from October 24th-November 13th, the ABI, GLM, SUVI, SEISS, and EXIS instruments will not be capturing or distributing data. GRB, DCS, HRIT/EMWIN, and SARSAT are disabled during drift. This is due to X-band radio frequency downlink interference. Only MAG will continue to collect data but with data outages during spacecraft maneuvers on October 24 and 25, 2018 and November 12 and 13, 2018.

Following two days of calibration activity after GOES-17 reaches 137.2 degrees west, all instruments will resume data distribution on November 15, 2018. At 1500 UTC, GOES-17 GRB, DCS, HRIT/EMWIN and SARSAT will be activated. GOES-17 will remain non-operational for an additional 3 weeks to allow for operational testing at the 137.2 degrees west position. M-BAfter successful test completion, the satellite will go into operations as the GOES-West satellite on December 10, 2018.

GOES-17 and GOES-15 will operate in tandem for six months from their respective locations of 137.2 degrees west and 128 degrees west, until a date is specified for disabling the GOES-15 GVAR. Additional information will be communicated as needed.

Key points:

Contact Information for Further Information: Kathryn Mozer at

Web Site(s) for applicable information:

See for additional information.

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