Please make a donation to support Gunter's Space Page.
Thank you very much for visiting Gunter's Space Page. I hope that this site is useful and informative for you.
If you appreciate the information provided on this site, please consider supporting my work by making a simple and secure donation via PayPal. Please help to run the website and keep everything free of charge. Thank you very much.

KH-9 Hexagon

KH-9 without MCS [NRO]

KH-9 with MCS [NRO]

KH-9 (Keyhole-9), also known as Hexagon or inofficially as "Big Bird", was a large reconnaissance satellite to replace the earlier KH-4B Corona satellites.

In contrast to earlier models, it was not based on the Agena stage, but on a new maneuverable bus called SCS (Satellite Control Section). It featured four return capsules for a much increased lifetime. The McDonnell Douglas manufactured Mk.8 return capsules were of a similar type as in the earlier Corona satellites and were designed to deorbit a film capsule from space with mid-air recovery of the returning capsule by a specially equipped aircraft.

The camera system was built by Perkin-Elmer and consisted of two large panoramic cameras for area surveillance with a forward looking camera on the port side, and an aft looking camera on the starboard side. Images were taken at altitudes ranging from 90 to 200 miles. The camera optical layout is an f/3.0 folded Wright Camera, with a focal length of 1.5 m. The system aperture is defined by a 0.51 m diameter aspheric corrector plate, which corrects the spherical aberration of the Wright design. In each of the cameras the ground image passes through the corrector plate to a 45 angle flat mirror, which reflects the light to a 0.91 m diameter concave main mirror. The main mirror directs the light through an opening in the flat mirror and through a four-element lens system onto the film platen. The cameras could scan contiguous areas up to 120 wide, and achieved a ground resolution better than 0.61 m during the later phase of the project.

12 of the 20 satellites featured also a mapping Camera System (MCS) mounted on the forward end with an own smaller Mk.5 return capsule. It was present on missions KH-9 5 to KH-9 16. The mapping camera or "frame camera" used 9 inch film and had a moderately low resolution of initially 9 m, which improved to 6 m on later missions. Intended for mapmaking, photos this camera took cover essentially the entire Earth with at least some images between 1973 and 1980.

Missions 1205 to 1207 carried Doppler beacons to map the atmospheric density at high altitudes in an effort to understand the effect on ephemeris predictions. The measurements of the atmospheric density were released through NASA.

The lifetime of the satellites increased from 40 days in the beginning to up to 275 days during the final missions.

Secondary Payloads

Some satellites carried secondary payloads mounted on the satellite:

  • KH-9 12 carried the STP S75-1 payload
  • KH-9 14 carried the STP S76-1 (NAVPAC 01) payload and the STP S77-2 (S3-4) payload
  • KH-9 17 carried the STP S81-1 (SEEP) payload
  • KH-9 19 carried the STP S85-1 (HVP-III) payload
  • KH-9 20 carried the STP S86-1 (RADC 801), GPSPAC 3 and RDBS payloads
Nation: USA
Type / Application: Reconnaissance, photo
Operator: USAF
Contractors: Lockheed (prime); Perkin-Elmer (cameras)
Equipment: ?
Configuration: SCS, 4 Mk.8 SRVs, 1 Mk.5 SRV (MCS versions only)
Propulsion: ?
Power: 2 deployable solar arrays, batteries
Lifetime: 40 - 275 days
Mass: 11400 kg
Orbit: 160 km × 260 km, 96.4 (typical)
Satellite COSPAR Date LS Launch Vehicle Remarks
KH-9 1 (Hexagon 1201, OPS 8709) 1971-056A 15.06.1971 Va SLC-4E Titan-3D
KH-9 2 (Hexagon 1202, OPS 1737) 1972-002A 20.01.1972 Va SLC-4E Titan-3D with P-11 4424
KH-9 3 (Hexagon 1203, OPS 7293) 1972-052A 07.07.1972 Va SLC-4E Titan-3D with P-11 4425
KH-9 4 (Hexagon 1204, OPS 8314) 1972-079A 10.10.1972 Va SLC-4E Titan-3D with P-801 4
KH-9 5 (Hexagon 1205, OPS 8410) 1973-014A 09.03.1973 Va SLC-4E Titan-3D
KH-9 6 (Hexagon 1206, OPS 8261) 1973-046A 13.07.1973 Va SLC-4E Titan-3D
KH-9 7 (Hexagon 1207, OPS 6630) 1973-088A 10.11.1973 Va SLC-4E Titan-3D with P-11 4426, P-801 5
KH-9 8 (Hexagon 1208, OPS 6245) 1974-020A 10.04.1974 Va SLC-4E Titan-3D with P-11 4428, IRCB
KH-9 9 (Hexagon 1209, OPS 7122) 1974-085A 29.10.1974 Va SLC-4E Titan-3D with P-11 4429, S3 1
KH-9 10 (Hexagon 1210, OPS 6381) 1975-051A 08.06.1975 Va SLC-4E Titan-3D with P-226 1
KH-9 11 (Hexagon 1211, OPS 5547) 1975-114A 04.12.1975 Va SLC-4E Titan-3D with S3 2
KH-9 12 (Hexagon 1212, OPS 4699) 1976-065A 08.07.1976 Va SLC-4E Titan-3D with P-11 4430, S3 3
KH-9 13 (Hexagon 1213, OPS 4800) 1977-056A 27.06.1977 Va SLC-4E Titan-3D
KH-9 14 (Hexagon 1214, OPS 0460) 1978-029A 16.03.1978 Va SLC-4E Titan-3D with P-11 4432
KH-9 15 (Hexagon 1215, OPS 3854) 1979-025A 16.03.1979 Va SLC-4E Titan-3D with P-11 4431
KH-9 16 (Hexagon 1216, OPS 3123) 1980-052A 18.06.1980 Va SLC-4E Titan-3D with P-801 6
KH-9 17 (Hexagon 1217, OPS 5642) 1982-041A 11.05.1982 Va SLC-4E Titan-3D with P-11 4433
KH-9 18 (Hexagon 1218, OPS 0721) 1983-060A 20.06.1983 Va SLC-4E Titan-34D with P-801 7
KH-9 19 (Hexagon 1219, USA 2) 1984-065A 25.06.1984 Va SLC-4E Titan-34D with P-11 4434
KH-9 20 (Hexagon 1220) 1986-F03 18.04.1986 Va SLC-4E F Titan-34D with Pearl Ruby