KH-7 (Keyhole 7) managed by NRO's Program A and operated this US Air Force system boasted long focal length cameras capable of identifying and measuring properties of targets such as missiles and aircraft, surpassing the resolution of the CORONA system. The spacecraft, a 3-axis-stabilized satellite separated from the Agena-D, housed the payload, camera system, and reentry vehicle (SRV), known as the OCV (Orbital Control Vehicle), built by General Electric. The KH-7 camera featured a 112 cm diameter primary mirror and achieved ground resolutions ranging from 0.61 m to 0.91 m, utilizing strip exposure techniques for capturing images with a swath width of 22 km and strip lengths of up to 741 km from its 167-kilometer orbit.

The Magnum satellite was part of a series of so called Program 11 or P-11 "Subsatellite Ferrets", low orbit ELINT/SIGINT satellites to pinpoint and characterize different Radar emitters in the Soviet Union and Warsaw pact states.