The KH-4B (Keyhole-4B) was sixth version in the Corona-program to build an optical reconnaissance satellite.
KH-4B carried two J-3 panoramic cameras, with a focal length of 61 cm, and a ground resolution of 1.8 m. The ground swath was 16 km × 217 km.
The DISIC (Dual Improved Stellar Index) camera provided a mapping capability superior to the KH-5 Argon system. The DISIC camera had a focal length of 91 cm, a ground resolution of 30 m, and frame coverage of 260 km × 260 km.
Secondary Payloads
Some satellites carried secondary payloads mounted on the satellite:
- KH-4B 9 carried the DB-1 (Doppler Beacon 1) payload
- KH-4B 10 carried the DB-2 payload
- KH-4B 12 carried the DB-3 payload
- KH-4B 13 carried the DB-4 payload
- KH-4B 14 carried the DB-5 payload
- KH-4B 15 carried the DB-6 payload
- KH-4B 16 carried the STP S71-3 payload
- KH-4B 17 carried the STP S71-5 payload
Several missions carried small "Subsatellite Ferret" satellites into orbit.