|Mission type||Infrared early warning|
|Operator||United States Air Force|
|Start of mission|
|Launch date||20 January 2018, 00:48UTC|
|Rocket||Atlas V 411 AV-076|
|Launch site||Cape Canaveral SLC-41|
The SBIRS satellites are a replacement for the Defense Support Program early warning system. They are intended to detect ballistic missile launches, as well as various other events in the infrared spectrum, including nuclear explosions, aircraft flights, space object entries and reentries, wildfires and spacecraft launches.
SBIRS-GEO 4 was manufactured by Lockheed Martin and is built upon the A2100M satellite bus. The Atlas V launch vehicle used for SBIRS-GEO 4 flew with a strap-on booster, a different configuration from the previous three SBIRS-GEO launches. This was done as part of a space debris mitigation effort, to allow the Centaur upper stage to preserve sufficient fuel for a deorbit burn.
The Air Force announced the satellite was operating as expected and had established initial communication with it.
- Clark, Stephan (20 January 2018). "U.S. military satellite launched to fortify against missile attacks". Spaceflight Now. Retrieved 20 January 2018.
- Erwin, Sandra (20 January 2018). "Air Force missile-warning command center makes contact with new SBIRS satellite". SpaceNews.com. Retrieved 24 January 2018.