The KH-9, also known as Hexagon or "Big Bird," was a large reconnaissance satellite designed to replace the earlier KH-4B Corona satellites. Unlike its predecessors, it utilized a new maneuverable bus called SCS (Satellite Control Section) and featured four return capsules for extended operational lifespan. Manufactured by McDonnell Douglas, the Mk.8 return capsules facilitated mid-air recovery of film capsules, similar to Corona satellites. The camera system, built by Perkin-Elmer, comprised two panoramic cameras for area surveillance, capturing images at altitudes ranging from 90 to 200 miles. These cameras utilized an f/3.0 folded Wright Camera optical layout with a 1.5 m focal length and achieved ground resolutions better than 0.61 m, scanning areas up to 120° wide.

The Tophat (sometimes also refered to by Top Hat) satellites were 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.

IRCB (Infra-Red Calibration Balloon) was a 66 cm diameter inflatable calibration sphere orbited in the Space Test Program. It was a piggyback payload on a KH-9 (Hexagon) spysat launch. The IRCB used an LPC-509 solid rocket motor to reach its own orbit. It was inflated upon separation from the launch vehicle. It was to serve as a calibration target for various other electromagnetic remote-sensing equipment. Internal battery power was provided.