[kstar]

Mike:

AFAIK, there at least three known "Hubble class" telescopes which are adapted to look down, not up - below says ground resolution is "probably 6 inches or better."

http://en.wikipedia.org/wiki/KH-12

"KH-12" is an unofficial designation of the successor to the KH-11 spy satellite. A system with the official designation KH-12 does not exist because the National Reconnaissance Office (NRO) decided to refer to satellites by a random numbering scheme after repeated public references to KH-8, KH-9, and KH-11 satellites.[1] It is also known as the "Advanced KENNENAN" or by the codenames Ikon and Improved Crystal. It is a successor to the KH-11 reconnaissance satellite and also used digital imaging. It is believed that the KH-12 improved upon the previous design by including signals intelligence capabilities and sensitivity in broader light spectrums (probably into infrared). Data is transmitted through a relay network of communications satellites. The satellite, with a mass of 19,600 kilograms, has been manufactured by Lockheed. Ground resolution is probably 0.15 meters (6 inches) or better. Like the KH-11 (Crystal), the KH-12 is believed to use a large mirror to capture light, and probably resembles the Hubble Space Telescope (HST) in size and shape.

As the "Improved Crystal" nickname implies, many believe that the KH-12 is largely an incremental improvement upon the KH-11, and a number of observers classify the spacecraft as a KH-11. Similarly, a successor KH-13 program may currently exist (some have called that a "KH-12B").

The spacecraft's mirror is believed to be 2.9-3.1 meters[2] somewhat larger than that of KH-11, believed to have a 2.3 meter diameter, and that of the HST, 2.4 m. Jane's Defence Weekly indicates that the secondary mirror in the Cassegrain reflecting telescope system can be moved significantly, allowing images to be taken from angles unusual for a satellite. Also, there are indications that the satellite can take images every five seconds. Sources vary on how the KH-12 communicates with ground stations. Several different clusters of relay satellites are available, so the birds may use the Satellite Data System (SDS), MILSTAR, or Tracking and Data Relay Satellite System (TDRSS) networks.

At least three were launched between February 1990 and December 1996, and others have probably been launched since. KH-12 satellites were launched on Titan IV rockets. Each satellite is estimated to have cost more than US $1 billion, and the launches cost close to $400 million.[3]
KH-12 satellites are believed to have been the source of some imagery of Russia and China made public in 1997, as well as images of Sudan and Afghanistan made public in 1998 that were related to the response to the 1998 U.S. embassy bombings.

See the link for references and such.