Northrop Grumman GSSAP

The GSSAP (Geosynchronous Space Situational Awareness Program) satellites have been developed by the USAF and Orbital Sciences (now Northrop Grumman) to provide a space-based space surveillance platform, to detect and track potential adversaries' space assets. The satellites operate near the GEO belt, and are capable of performing so-called Rendezvous and Proximity Operations (RPO), i.e., they can maneuver towards other objects in GEO to inspect them at close range. The satellites are also known by the name "Hornet".

Image: USSF

GSSAP

As of February 2026, eight GSSAP satellites have been put into orbit, two each on four launches. Of these, seven are still active, since USA 254 (GSSAP 2) has been deactivated in July 2023. Two additional satellites are planned to be launched in 2027 or later.

GSSAP Launch List

• No.: Sequential satellite number for the GSSAP (Hornet) program
• Name: Unclassified name of the satellite. Since June 1984, U.S. military satellites get a sequential "USA" number.
• COSPAR ID: International designation of the satellite

GSSAP launches

Main Sources

[1] Wikipedia: Space Based Space Surveillance
[2] Gunter Krebs: GSSAP 1, ..., 10 (Hornet 1, ..., 10)
[3] USSF: Geosynchronous Space Situational Awareness Program

Back to Directory of U.S. Military Rockets and Missiles, Appendix 3

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Last Updated: 15 February 2026