| EWS-G2 | |
| Names List: | GOES-P GOES-15 |
| Mission Type: | Weather satellite |
| Operator: | NOAANASA |
| Cospar Id: | 2010-008A |
| Satcat: | 36411 |
| Mission Duration: | 10 years (planned) Elapsed: |
| Spacecraft Type: | GOES-N series |
| Spacecraft Bus: | BSS-601 |
| Manufacturer: | Boeing ITT Corporation |
| Power: | 2.3 kilowatts from solar array |
| Launch Date: | UTC |
| Launch Rocket: | Delta IV-M+(4,2) |
| Launch Site: | Cape Canaveral, SLC-37B |
| Launch Contractor: | United Launch Alliance |
| Orbit Reference: | Geocentric |
| Orbit Regime: | Geostationary |
| Orbit Semimajor: | 42166km (26,201miles) |
| Orbit Periapsis: | 35791km (22,239miles) |
| Orbit Apoapsis: | 35800.4km (22,245.3miles) |
| Orbit Inclination: | 0.2° |
| Orbit Period: | 1,436.2 minutes |
| Orbit Longitude: | 128° West |
| Orbit Slot: | GOES-West |
| Apsis: | gee |
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.
GOES-15 was launched atop a Delta IV-M+(4,2) rocket flying from Space Launch Complex 37B at the Cape Canaveral Air Force Station.[3] [4] The launch occurred at 23:57 UTC on 4 March 2010, forty minutes into a sixty-minute launch window. Upon reaching geostationary orbit on 16 March, it was redesignated GOES-15.[4] [5] On 6 December 2011, it was activated as the GOES-West satellite, replacing GOES-11.[6]
At launch, the mass of the satellite was . It has a design life of ten years. Power is supplied by a single gallium arsenide solar 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]
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. 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. 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. 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]