KH-11 / Kennen / Crystal

The KH-11 series of reconnaissance satellites, also known by their Byeman code names Kennen (the often reported "Kennan" is likely a misspelling) and Crystal (since 1982), are the first American spy satellites to utilize electro-optical digital imaging, and provide a real-time optical observation capability. They replaced the earlier film-return type satellites of the KH-8 Gambit-3 and KH-9 Hexagon series.

The satellites are believed to use a 2.4 m diameter prime mirror, which would proved a theoretical ground resolution of 15 cm. Operational resolution would be worse due to effects of the atmosphere. Reportedly some ELINT equipment is also carried. Prime contractor for the KH-11 satellites is Lockeed (now Lockheed Martin).

The KH-11 series transmit their data via relay satellites called Satellite Data System (SDS-1, SDS-2, SDS-3), which operate in Molniya orbits and geostationary orbits.

The KH-11 satellites were built in several blocks, each introducing improvements. The optical system remained probably mostly unchanged, while sensors and avionics have been improved. With the advent of the more powerful Titan-4 launch vehicle, the amount of fuel has likely been increased for a longer lifetime.

• Block 1 (KH-11 1-5): Original version
• Block 2 (KH-11 6-9): Improved infra-red capabilities, higher apogee
• Block 3 (KH-11 10-12, 14): Improved Metric CRYSTAL System" (IMCS), which adds reference markings for accurate mapping to images obtained by the satellite; more fuel for longer life time; built for Space Shuttle deployment and servicing
• Block 4 (KH-11 13, 15-16): Unknown improvements; Space Shuttle related equippment removed

The satellites of Block 3 and 4 are hence often dubbed "advanced Crystal". Likely the often reported designation "KH-12" is not correct and they are likely also called KH-11. The Byeman code name Ikon has been reported for this series.

The 8X or EIS program was planned as a replacement, but was finally cancelled due to escalting costs.

The FIA optical satellites were designed as their successors, but with continuing delays and finally the collapse of the FIA optical program, two more satellites (Block 5 ?) were procured.

The relation to the stealthy Misty satellites is unclear, but Misty might be derived from the KH-11 design.