The Strawman series of ELINT/SIGINT satellites, known for decades only as "Heavy Ferrets", are the fourth variation of Agena-based ELINT satellites. These satellites were designed to detect, map and investigate SAM and ABM radars.

Mission type: Government/Top Secret · Orbit: Low Earth Orbit

Rocket: Thorad SLV-2H Agena D · Provider: United States Air Force