GOES-N to GOES-13, EWS-G1 and the Graveyard (Orbit)
The Imager on GOES-13 captured approximately 2,307,267 images (counting each of the 5 spectral bands as an image), with an additional (at least) 264,480 images as EWS-G1 — for a total of 2,571,747 images! In addition, the GOES-13 Sounder captured 3,054,820 images (counting each of the 19 spectral bands as an image).
GOES-N and GOES-13
After years of planning, GOES-N was launched in the Spring of 2006. The spacecraft was built by Boeing, while the Imager and Sounder were both built by (then) ITT Industries, Inc., as part of a series (GOES-N/O/P). After reaching the geostationary orbit, it was renamed GOES-13 and there was a post-launch test (PLT) period to verify its operational readiness (which produced a NOAA Technical Report: Hillger and Schmit). More on the GOES-13 PLT, including results from both the Imager and Sounder, is available here. A University of Wisconsin-Madison/SSEC story (“Changing the GOES line-up“) from 2006.
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“The latest Geostationary Operational Environmental Satellite (GOES), GOES-N, was launched on 24 May 2006, and reached geostationary orbit at 89.5°W on 4 June 2006 to become GOES-13. It was later moved to 105ºW for the Science Test and eventual storage. The National Oceanic and Atmospheric Administration (NOAA)/National Environmental Satellite, Data, and Information Service (NESDIS) conducted a 3-week GOES-13 Science Test that began 7 December 2006 and ended officially on 28 December 2006. The Science Test schedule was integrated within the NESDIS/National Aeronautics and Space Administration (NASA) GOES- 13 Post-Launch Test (PLT) schedule. GOES-13 has instruments similar to those on GOES-8/12,but is on a different spacecraft bus. The new bus allows improvements both to navigation and registration, as well as the radiometrics. By supplying data through the eclipse periods, the GOES-N/O/P system addresses one of the major limitations which are eclipse and related outages. This is possible due to larger spacecraft batteries. Outages due to Keep Out Zones (KOZ) will be minimized.“
FROM THE 2008 NOAA Report
After the PLT checkout and handover from NASA to NOAA, GOES-13 was placed in on-orbit storage until it was put into operational use beginning in April of 2010. In 2012, there was an outage, while GOES-14 provided support. In 2013, the spacecraft was hit with a micrometeor, but the spacecraft was reactivated after spending two and a half weeks in safe mode. GOES-13 was featured in hundreds of entries on the CIMSS Satellite Blog covering many of the Earth-looking uses, including severe weather, fires, fog, smoke, etc. It ended operational service for NOAA in January of 2018, and was an in-orbit backup satellite until being transferred to the U.S. Space Force in 2019.
GOES-13 Became EWS-G1
EWS-G1 (Electro-optical Infrared Weather System Geostationary) is a U.S. Space Force mission. The imager is running a routine scan schedule, as can be seen on the UW/SSEC geo-browser. This schedule includes scans of the Indian Ocean, the extended Indian Ocean and Full Disks. Previously only Full Disk images had been obtained every 30 minutes (see this EWS-G1 quick-guide). EWS-G1 imagery has been available via the UW/SSEC since late 2020. While operating over the Indian Ocean, the Imager monitored many phenomena, including many typhoons. Beginning in June of 2023, EWS-G1 has employed the “XGOHI” remapping of data before GVAR generation, to handle larger satellite inclination angles, increasing the time of providing quality imagery. This capability was first employed on GOES-10 (and then GOES-12) when their images provided special coverage of the Southern Hemisphere for a combined almost 7 years.
GOES-15 has become EWS-G2
It was recently announced by the Secretary of the Air Force that GOES-15 has become EWS-G2: “The U.S. Space Force accepted the transfer of a second geostationary weather satellite from the National Oceanic and Atmospheric Administration to extend persistent weather coverage of the Indian Ocean region until the 2030 timeframe. … As it currently does with EWS-G1, NOAA will operate EWS-G2 on behalf of the Space Force from the NOAA Satellite Operations Facility in Suitland, Maryland, and Wallops Command and Data Acquisition Station in Wallops Island, Virginia.”
The above loop is available as an mp4 and an animated gif.
EWS-G2 has the same spectral coverage as the EWS-G1. The EWS-G2 was formerly NOAA’s GOES-15, which was launched in March 2010 and the first GOES-15 images were sent on April 6, 2010 (see this GOES-15 technical report, which was written soon after launch). EWS-G2 is now routinely sending data.
Last Image and “Graveyard” Orbit
The above image was intentionally offset to allow for special end of satellite life data collection for calibration purposes of the other GOES-N/O/P series Imagers.
EWS-G1 will soon be placed in a “super synchronous” (or “graveyard“) higher orbit – hence an end of an era. Thanks to GOES-13/EWS-G1 for much valuable data over the years.
More
The posted near realtime imagery are free for public use (please credit UW-Madison/SSEC) and users can contact UW/SSEC Satellite Data Services for information on data access / subscription. Most of the above images were made using the McIDAS-X software. NOAA/NESDIS/STAR supplies some calibration support of these imagers.
History has been repeated, as GOES-1, after it’s operational use, was moved in the late 1970s to collect imagery over the Indian Ocean — and this has happened once again with GOES-13 and GOES-15 becoming EWS-G1 and EWS-G2.