NEMESIS
In 2006, Lockheed Martin received a contract to build and launch a satellite for an undisclosed government entity within only 30 months from contract award. The satellite used Lockheed Martin's commercial A2100 satellite bus, and was referred to by the project number P360. When it was eventually launched into a geosynchronous orbit on 8 September 2009, the satellite had been given the name PAN. PAN officially stood for "Palladium at Night", whatever that was supposed to mean.
At the time of launch, it was totally unclear, what the mission of the satellite is and which agency owns it. But amateur observations of its orbit and some leaked documents eventually formed a consistent picture. PAN is the first satellite of an NRO program named NEMESIS. It is a SIGINT program to eavesdrop on the transmissions of commercial geosynchronous satellites for telephony connections. To do this, PAN maneuvered itself into a co-orbit with the target satellite and followed it for as long as needed for a specific objective. By 2014, this moving from one target satellite to the next had stopped, so PAN has possibly taken over a different mission at that time. In the early 2020s, PAN started again to maneuver in GEO.
 |
| Image: NSA / Lockheed Martin(?) |
| NEMESIS 1 (PAN) |
On 17 September 2014, a satellite named CLIO was launched into a GEO orbit. Just like PAN, CLIO was built by Lockheed Martin, based on the A2100 bus, and no owner was officially announced. Because of these parallels, it is generally assumed that CLIO is the second satellite of the NEMESIS program.
NEMESIS Launch List
- No.: Sequential flight number for the NEMESIS program
- Name: Unclassified name of the satellite. Since June 1984, all U.S. military satellites get a sequential "USA" number. The two NEMESIS satellites also received an additional individual name in public announcements.
- COSPAR ID: International designation of the satellite
| No. | Name | COSPAR ID | Launch | Launch Vehicle |
|---|---|---|---|---|
| 1 | USA 207 / PAN | 2009-047A | 8 Sep 2009 | Atlas-5(401) |
| 2 | USA 257 / CLIO | 2014-055A | 17 Sep 2014 | Atlas-5(401) |
NEMESIS launches
Main Sources
[1] Marco Langbroek: A NEMESIS in the sky, The Space Review, October 2016
[2] NSA: Two New Collection Assets
to Greatly Expand MHS Target Coverage, SIDtoday, January 2009
[3] Gunter's Space Page (for launch lists)
Back to Directory of U.S. Military Rockets and Missiles, Appendix 3
Last Updated: 23 August 2025