Geosynchronous Space Situational Awareness Program

Geosynchronous Space Situational Awareness Program (GSSAP) or Hornet is a class of United States spy satellites.

The first two GSSAP spacecraft , GSSAP 1 (USA-253) and GSSAP 2 (USA-254) were launched in 2014. They were built by Orbital Sciences Corporation; their capabilities and development and construction budgets are classified. They operate in "near-geosynchronous orbit",^[1][2] The first launch was scheduled for 23 July 2014 aboard a United Launch Alliance Delta IV launch vehicle.^[3] Even during the testing process these satellites were pressed into early service to fulfill critical needs.^[4] In August 2023 the Space Systems Command announced the retirement of the GSSAP-2 satellite, the first of the constellation to be decommissioned, and its subsequent transfer into a graveyard orbit.

GSSAP 3 (USA-270) and 4 (USA-271) satellites were launched on 19 August 2016. On 12 September 2017, both were declared operational.^[5] USA-270 approached two Chinese satellites in GEO to examine them more closely.^[6] In 2023, Chinese researchers reported having observed 13 other instances where US satellites approached Chinese ones.^[7]

Two more satellites (GSSAP-5 and GSSAP-6) have been successfully launched on 21 January 2022 by a Atlas V launch vehicle.^[8]

In August 2023 the Space Systems Command revealed that two more satellites have been ordered to Northrop Grumman to keep up with the demand for GSSAP assets.^[9] The launches of the new satellites were planned for 2024 and 2027 respectively, with the spacecraft being the first of the constellation not to be launched in pairs.^[10]

GSSAP 7 and 8 are scheduled to be launched together in 2025 by a Vulcan Centaur VC4S.^[11][12][13] GSSAP 9 and 10 will follow in 2027.^[11]