KENNEN / CRYSTAL

In the 1960s, all U.S. photo-reconnaissance satellites returned photographic film, which had been exposed in orbit, via reentry vehicles back to Earth. Even though transmitting image information from the satellite to Earth with radio signals was regarded as desirable from the beginning (see WS-117L/SAMOS), 1960s technology was just not mature enough to successfully implement it. But this had changed by 1970, and in 1971, the development of an electro-optical imaging reconnaissance satellite was approved. The system was initially code-named ZAMAN, but the name was finalized to KENNEN in November 1971. The ultimate goal of KENNEN was to replace both HEXAGON/KH-9 as wide-area reconnaissance system and GAMBIT-3/KH-8 for high-resolution target photography. The unclassified numerical code for KENNEN was Program 1010, and the optical reconnaissance system was designated KH-11. Prime contractor for the system became Lockheed (now Lockheed Martin).

KENNEN is still classified, and therefore almost all specific information is effectively unconfirmed. It seems to be certain, though, that the satellite design is closely related to NASA's Hubble Space Telescope (HST). It uses a large primary mirror, with a diameter of 2.34 m (92 in) in the first satellites, but later enlarged to around 3 m (20 in). The light was initially collected by an array of light-sensitive diodes, but that was changed to a CCD (Charge-Coupled Device) in the second satellite, basically pioneering what is nowadays standard technology for digital photography. The images are transmitted to ground stations using SDS (Satellite Data System) communication satellites as high-bandwidth relays. The best-case ground resolution of KH-11 is expected to be in the order of 15 cm (6 in) or better.

Drawings: Guiseppe di Chiara, CC BY-SA 3.0

KENNEN (KH-11); speculative notional drawing, based on HST

The first KENNEN satellite was launched on 19 December 1976, followed by one each in 1978, 1980, 1981 and 1982. All used the Titan IIID as launch vehicle. Nominally, a complete KH-11 constellation consists of at least 4 satellites, two each in sun-synchronous orbits in two orbital planes. These planes are separated by about 50 degrees of longitude. The orbits are timed in a way that satellites in the eastern plane see the ground at afternoon hours, while the satellites in the western plane see it at morning hours. This way, all observations make use of shadows to enhance the height profile of any structures. In each plane, one satellite is the primary one, while the secondary one is 10-20 degress east of the primary in the eastern plane, and west of it in the western plane. The first five KENNEN satellites are usually referred to by observers as "Block 1". They all had similar orbits of around 270 km × 500 km. Because the lifetime of each KENNEN satellite is no longer limited by the amount of film and the number of reentry vehicles, they can stay operational until either a critical failure occurs or the fuel needed for orbital adjustments and attitude control is exhausted.

Image: Wikimedia, CC BY-SA 3.0

KH-11 constellation as of Sept. 2013

In 1982, the name of the KH-11 satellite system was changed to CRYSTAL. The next four launches, between December 1984 and November 1988, placed three CRYSTAL satellites (one launch failed to reach orbit) in slightly higher orbits, around 300 km × 1000 km. The higher orbits can significantly extend the lifetime of each satellite, because less fuel is needed to compensate for atmospheric drag. The launch vehicle was the Titan 34D. Because of the significant changes, these satellites have been referred to as "Block 2". It is suspected that they feature some major improvements, including an imaging infrared sensor.

Beginning with satellite USA-86, launched in November 1992, the larger Titan 4A was used as a launcher. This one and the following three KH-11 satellites, up until USA-161 in October 2001, are usually called the "Block 3" variant of CRYSTAL. From leaked information, it is known that these satellites were equipped with the so-called "Improved Metric CRYSTAL System" (IMCS), which added reference markers to its photos to indicate the geolocation with very high precision. Another improvement was the much higher data rate when transmitting data via the SDS network. The "Block 3" satellites are sometimes called "KH-12", "Advanced CRYSTAL" or IKON, but these labels are probably all fictitious. The more powerful launch vehicle hints at a higher launch mass, indicating a higher fuel load for longer mission times. On-orbit time of a CRYSTAL "Block 3" was around 15 years or more.

In the late 1990s, a follow-on program for KH-11 was started under the name FIA-O (Future Imagery Architecture - Optical). The development contract was eventually awarded to Boeing in 1999. However, delays and cost overruns led to the cancellation of FIA-O in 2005, and an order to Lockheed Martin to deliver two additional KH-11 platforms. The latter were eventually launched as USA-224 and USA-245 in January 2011 and August 2013, respectively. These satellites used yet another more powerful launcher, the Delta 4 Heavy, and are usually referred to as KH-11 "Block 4". There is no information about improvements (if any) in "Block 4". It is possible, that they are more or less identical to the "Block 3", but it is also possible, that some of the features which had been planned for the enigmatic EIS (Enhanced Imaging System) program have found their way into KH-11 "Block 4". Interestingly, satellite USA-186, launched in 2005 as the last of the originally planned KENNEN/CRYSTAL missions, is usually also listed as "Block 4", even though it used the Titan 4 launch vehicle like all the other "Block 3" vehicles.

It must be noted that none of the KENNEN/CRYSTAL flights were officially acknowledged as such. Instead they were always referenced as classified NRO payload. But up to USA-245, the last alleged KH-11 "Block 4", the orbits were matching what was expected from a KH-11 mission. Therefore, there is little doubt that the satellites in the following launch list are correctly identified as KH-11.

KENNEN/CRYSTAL (KH-11) Launch List

• Name / Launch: Unclassified name of the satellite. The OPS number ("OPS" standing for "Operations") is a random number given to all military-related satellite launches between 1963 and May 1984. Since June 1984, U.S. military satellites get a sequential "USA" number. "NROL" stands for National Reconnaissance Office Launch, a number assigned by the NRO to its satellite launches since 1996.
• Block: Unofficial "Block" number of satellite
• COSPAR ID: International designation of the satellite; not applicable, if orbit was not reached

KENNEN/CRYSTAL (KH-11) launches

As of June 2025, USA-186, -224 and -245 are still in orbit.

KH-11 "Block 5"

Roughly around 2010, Lockheed Martin received a contract to build new electro-optical imaging satellites. It is assumed that these are based on the KH-11 "Block 4", but the amount of modifications (if any) is completely unknown. Based on the Delta-4 Heavy launch vehicles and the eventual orbits, the satellites USA-290, USA-314 and USA-338 probably belong to this new batch of reconnaissance satellites. They are sometimes labeled KH-11 "Block 5". But even though the identification of these satellites as electro-optical imaging systems is plausible, it is must be regarded as unconfirmed. As of June 2025, all the alleged "Block 5" satellites are still in orbit.

KH-11(?) "Block 5" launches

MISTY/EIS

There are another two satellites, which might be directly connected to the KH-11 CRYSTAL program, but where this connection is even less tangible than for the so-called KH-11 "Block 5". The first of these, USA-53, was launched with Space Shuttle Atlantis on 28 February 1990. It was officially part of Air Force Program (AFP-) 731, and rumored to be code-named MISTY. After release from the Shuttle, USA-53 was effectively untrackable for amateurs, and was frequently referred to as a "Stealth Satellite". It's not unlikely, that specific measures have been taken to reduce its optical signature, e.g. by coating it with a special black color reflecting almost no light at all.

In the 1990s, a successor for KH-11 was planned under the name EIS (Enhanced Imaging System), originally "8X". Prime contractor was Lockheed Martin, and the EIS satellite was expected to be a modified variant of CRYSTAL "Block 3". Officially, the EIS program was cancelled before the first satellite was completed. However, in May 1999 the NRO launched USA-144, and it seems to be widely accepted, that it was an imaging satellite in the same general "class" as the KH-11. Sources disagree on which specific program USA-144 belonged to - some list it as launch #2 of the MISTY program, but it is also sometimes attributed to the EIS program.

Launches possibly related to KH-11

Main Sources

[1] David Baker: "US Spy Satellites", Haynes Publishing, 2016
[2] Gunter Krebs: Gunter's Space Page (for launch lists)

Back to Directory of U.S. Military Rockets and Missiles, Appendix 3

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Last Updated: 25 June 2025