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"[0]
...
"In January 2011, NRO donated to NASA two space Optical Telescope Assemblies with 2.4 meters (94 in) diameter primary mirrors... The mirrors are to be used by NASA as the primary and spare for the Roman Space Telescope. "[0][1]
[0] https://en.wikipedia.org/wiki/KH-11_KENNEN#Derivatives
[1] https://en.wikipedia.org/wiki/Nancy_Grace_Roman_Space_Telesc...
