KH-11 Missions
Nine KH-11 satellites were launched between 1976 and 1990 aboard Titan-3D and −34D rockets, with one launch failure. For the following five satellite launches between 1992 and 2005, a Titan IV launch vehicle was used. The most recent launch in 2011 was carried out by a Delta IV Heavy rocket. The KH-11 replaced the KH-9 film return satellite, among others, the last of which was lost in a liftoff explosion in 1986.
KH-11 satellites are in either of two standard planes in Sun-synchronous orbits. As shadows help to discern ground features, satellites in a standard plane east of a noon/midnight orbit observe the ground at local afternoon hours, while satellites in a western plane observe the ground at local morning hours. Historically launches have therefore been timed to occur either about two hours before or one hour after local noon (or midnight), respectively.
| Name | KH-11 Block |
Launch date | ID | NROL number | Orbit | Plane | Orbital decay date |
|---|---|---|---|---|---|---|---|
| OPS 5705 | 1-1 | 19 December 1976 | 1976-125A | N/A | 247 km × 533 km, i=96.9° | West | 28 January 1979 |
| OPS 4515 | 1–2 | 14 June 1978 | 1978-060A | 276 km × 509 km, i=96.8° | West | 23 August 1981 | |
| OPS 2581 | 1–3 | 7 February 1980 | 1980-010A | 309 km × 501 km, i=97.1° | East | 30 October 1982 | |
| OPS 3984 | 1–4 | 3 September 1981 | 1981-085A | 244 km × 526 km, i=96.9° | West | 23 November 1984 | |
| OPS 9627 | 1–5 | 17 November 1982 | 1982-111A | 280 km × 522 km, i=96.9° | East | 13 August 1985 | |
| USA-6 | 2-1 | 4 December 1984 | 1984-122A | 335 km × 758 km, i=98° | West | 10 November 1994 | |
| Unknown | 2-2 | 28 August 1985 | N/A | Failed to orbit | East | N/A | |
| USA-27 | 2–3 | 26 October 1987 | 1987-090A | 300 km × 1000 km, i=98° | East | 11 June 1992 | |
| USA-33 | 2–4 | 6 November 1988 | 1988-099A | 300 km × 1000 km, i=98° | West | 12 May 1996 | |
| USA-86 | 3-1 | 28 November 1992 | 1992-083A | 408 km × 931 km, i=97.7° | East | 5 June 2000 | |
| USA-116 | 3-2 | 5 December 1995 | 1995-066A | 405 km × 834 km, i=97.7° | East | 19 November 2008 | |
| USA-129 | 3-3 | 20 December 1996 | 1996-072A | NROL-2 | 292 km × 894 km, i=97.7° | West | |
| USA-161 | 4-1 | 5 October 2001 | 2001-044A | NROL-14 | 309 km × 965 km, i=97.9° | East | |
| USA-186 | 3–4 | 19 October 2005 | 2005-042A | NROL-20 | 256 km × 1006 km, i=97.9° | West | |
| USA-224 | 4-2 | 20 January 2011 | 2011-002A | NROL-49 | 290 km × 985 km, i=97.9° | East |
KH-11 satellites require periodic reboosts to counter atmospheric drag, or to adjust their ground track to surveillance requirements. Based on data collected by amateur observers, the following orbital characteristics of OPS 5705 were calculated by amateur skywatcher Ted Molczan.
| OPS 5705 Time period |
Periapsis (AMSL) |
Apoapsis (AMSL) |
Apogee at end of period (AMSL) |
|---|---|---|---|
| 19 December 1976 – 23 December | 253 km (157 mi) | 541 km (336 mi) | 541 km (336 mi) |
| 23 December 1976 – 27 March 1977 | 348 km (216 mi) | 541 km (336 mi) | 537 km (334 mi) |
| 27 March 1977 – 19 August | 270 km (170 mi) | 537 km (334 mi) | 476 km (296 mi) |
| 19 August 1977–1978 January | 270 km (170 mi) | 528 km (328 mi) | 454 km (282 mi) |
| 1978 January – 28 January 1979 | 263 km (163 mi) | 534 km (332 mi) | Deorbited |
Read more about this topic: KH-11 Kennan
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