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 were launched in 2014, and a further two was launched on 19 August 2016 (USA-270 and USA-271). The first two were built by Orbital Sciences Corporation; their capabilities and development and construction budgets are classified. They operate in "near-geosynchronous orbit", The first launch was scheduled for 23 July 2014 aboard a United Launch Alliance Delta IV launch vehicle.

Even during the testing process these satellites were pressed into early service to fulfill critical needs.

On 12 September 2017, the third and fourth satellites were declared operational.

Two more satellites (GSSAP-5 and GSSAP-6) have been successfully launched on 21 January 2022 by a Atlas V launch vehicle. USA-270 approached two Chinese satellites in GEO to examine them more closely. In 2023, Chinese researchers reported having observed 13 other instances where US satellites approached Chinese ones.

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. Moreover, it revealed that two more satellites have been ordered to Northrop Grumman to keep up with the demand for GSSAP assets. The launches of the new satellites are planned for 2024 and 2027 respectively, with the spacecraft being the first of the constellation not to be launched in pairs.