Weather System Follow-on Microwave

{{Short description|American meteorology satellite}}

{{Use American English|date=February 2021}}

{{Use dmy dates|date=February 2021}}

{{Infobox spaceflight

| name = Weather System Follow-on Microwave-1

| names_list = WSF-M1

| image =

| image_caption =

| image_size = 300px

| mission_type = Space weather

| operator = USSF

| COSPAR_ID =

| SATCAT =

| website =

| mission_duration =

| spacecraft =

| spacecraft_type =

| spacecraft_bus =

| manufacturer = Ball Aerospace & Technologies

| launch_mass =

| dimensions =

| power =

| launch_date = 11 April 2024, 14:25 UTC

| launch_rocket = Falcon 9 Block 5 Cargo

| launch_site = Vandenberg

| launch_contractor = SpaceX

| entered_service =

| deactivated =

| last_contact =

| decay_date =

| orbit_reference = Geocentric orbit

| orbit_regime = Sun-synchronous orbit

| orbit_periapsis =

| orbit_apoapsis =

| orbit_inclination =

| orbit_period =

| apsis = gee

| instruments = Microwave imaging radiometer

| insignia =

| insignia_caption =

| insignia_size = 200px

| programme = Weather System Follow-on Microwave program

| previous_mission = DMSP-19

| next_mission = WSF-M2

}}

The Weather System Follow-on Microwave (WSF-M) satellite is the United States Department of Defense's next-generation operational environmental satellite system. WSF-M will be a Sun-synchronous low Earth orbit (LEO) satellite with a passive microwave imaging radiometer instrument and hosted furnished Energetic Charged Particle (ECP) sensor.{{cite web |url=https://directory.eoportal.org/web/eoportal/satellite-missions/content/-/article/wsf-m |title=WSF-M (Weather System Follow-on - Microwave) Satellite |work=eoPortal |publisher=ESA |date=March 2021 |access-date=24 May 2021}}{{cite news|last1=Russell|first1=Kendall|title=Ball Aerospace Wins Air Force Contract for New Weather Satellite|url=https://www.satellitetoday.com/telecom/2017/11/30/ball-aerospace-wins-air-force-contract-new-weather-satellite/|publisher=Satellite Today|date=30 November 2017|access-date=13 December 2017}} Space Operations Command intends to include ECP sensors on all future satellites for space weather monitoring, starting from the early 2020s.{{cite news|last=Werner|first=Debra|title=Are small satellites the solution for space weather monitoring?|url=https://spacenews.com/are-small-satellites-the-solution-for-space-weather-monitoring/|work=SpaceNews|date=6 March 2019|access-date=13 October 2019}} WSF-M was launched in April 2024 on a Falcon 9 Block 5 rocket from Vandenberg Space Force Base.{{cite tweet |user=USSF_SSC |number=1529969683671134209|title=SSC ordered 8 National Security Space Launch missions from our industry partners ULA & SpaceX for launch in 2024 for #SpaceForce. |date=27 May 2022 |access-date=27 May 2022}}{{cite web |url=https://www.ball.com/aerospace/newsroom/blogs/ball-aerospace-ships-wsf-m-satellite-for-launch |title=Ball Aerospace Ships Space Systems Command Operational Weather Satellite for Launch |date=6 February 2024 |access-date=8 February 2024}}

WSF-M is the first satellite in the Weather System Follow-on (WSF) program. Following the cancellation of the National Polar-orbiting Operational Environmental Satellite System (NPOESS), the Air Force continued the development of a weather satellite under the Defense Weather Satellite System (DWSS) program based on NPOESS. However, when that system faced delays and funding issues, the White House cancelled it and instituted the WSF program.{{cite news|title=USAF Weather Satellite Program in Disarray|url=http://www.defense-aerospace.com/articles-view/release/3/181430/us-air-force-weather-satellite-program-in-disarray.html|website=defense-aerospace.com|access-date=13 December 2017|date=23 February 2017}}

WSF-M is designed to mitigate three high priority U.S. DoD Space-Based Environmental Monitoring (SBEM) gaps: ocean surface vector winds, tropical cyclone intensity and LEO energetic charged particles.