EWS-G2 (Electro-optical Infrared Weather System Geostationary)[1] is a weather satellite of the U.S. Space Force, formerly GOES-15 (also known as GOES-P before becoming operational). The spacecraft was constructed by Boeing, and is the last of three GOES satellites to be based on the BSS-601 bus. It was launched in 2010, while the other BSS-601 GOES satellites—GOES-13 and GOES-14—were launched in May 2006 and June 2009 respectively.[2] It was the sixteenth GOES satellite to be launched.
At launch, the mass of the satellite was 3,238 kilograms (7,139 lb). It has a design life of ten years. Power is supplied by a single gallium arsenidesolar panel, which provides up to 2.3 kilowatts of power. A 24 cell nickel hydrogen battery is used to provide power when the satellite is not in sunlight.[7] Instruments aboard GOES-15 include a five channel multispectral imager to capture visible light and infrared images of the continental United States, a sounder to take readings of atmospheric temperature and moisture, a solar x-ray imager to detect solar flares, and instruments to monitor the magnetosphere, cosmic background radiation and charged particles.[7]
Operations
NOAA began to transition GOES-15 out of operational status at the GOES-West position in late 2018 to replace it with GOES-17.[8][9]GOES-15 began an eastward drift maneuver on 29 October 2018 to 128° W, with all of its sensors still functioning.[9] GOES-15's drift is intended to provide additional separation from GOES-17 to prevent communication interference. GOES-15 drifted east at a rate of 0.88° per day until 7 November 2018, when it reached its new operating location of 128° West. Once GOES-17 reached its assigned longitude on 13 November 2018, additional tests were performed; provided that testing goes well, GOES-17 will become operational as GOES-West on 10 December 2018.[9] Both GOES-17 and GOES-15 operated in tandem through early 2020 to allow for assessment of the performance of GOES-17 as the GOES-West operational satellite.[9] On March 2, 2020, GOES-15 was deactivated and moved to a storage orbit, with plans to re-activate it in August 2020 to back up GOES-17 operations due to a known flaw causing many sensors to become unreliable at night during certain times of the year.[10][11] On 22 September 2023 the satellite's ownership was officially transferred to the U.S. Space Force, taking its current designation as part of the EWS-G network. As a consequence, the spacecraft has started drifting over the Indian Ocean to reach its new assigned orbit and it's scheduled to become operational in November 2023.[1]
Launches are separated by dots ( • ), payloads by commas ( , ), multiple names for the same satellite by slashes ( / ). Crewed flights are underlined. Launch failures are marked with the † sign. Payloads deployed from other spacecraft are (enclosed in parentheses).
