[lizknope]

https://en.wikipedia.org/wiki/KH-11_KENNEN

We don't know how much of it is the same but the mirror is very similar.

> KH-11s are believed to resemble the Hubble Space Telescope in size and shape, as they were shipped in similar containers. Their length is believed to be 19.5 meters, with a diameter of up to 3 meters (120 in).[5][23] A NASA history of the Hubble,[24] in discussing the reasons for switching from a 3-meter main mirror to a 2.4-meter (94 in) design, states: "In addition, changing to a 2.4-meter mirror would lessen fabrication costs by using manufacturing technologies developed for military spy satellites".

> In January 2011, NRO donated to NASA two space Optical Telescope Assemblies with 2.4 meters (94 in) diameter primary mirrors,[53][54][55][56] similar in size to the Hubble Space Telescope, yet with steerable secondary mirrors and shorter focal length (resulting in a wider field of view). These were initially believed to be KH-11 series "extra hardware", but were later attributed to the cancelled Future Imaging Architecture program.[57] The mirrors are to be used by NASA as the primary and spare for the Roman Space Telescope.