By keeping the development of new satellite technology in the CIA, Wheelon was able to guide the direction of the technology. To him, the solution seemed obvious. Television stations could beam live images of football games across the country instantly, why couldn't the CIA's satellites transmit reconnaissance images from orbit?
The image tubes that TV cameras of the day used were too fragile and low resolution to use in orbit, but he found a promising new technology in AT&T's Bell Labs. Charge-coupled devices, or CCDs showed immense potential as electronic image sensors, but at the time the technology was still in its infancy. To keep the research alive, Wheelon started directing agency funds to support the lab's work on CCDs.
Wheelon left the CIA for the Hughes Aircraft Company in 1966, but his legacy continued as the CIA continued to support Bell Labs's CCD cameras. In 1976 the KH-11 KENNEN spy satellite was launched carrying the first electronic eye into orbit. It revolutionized the way we looked at Earth which revolutionized how we look at the rest of the universe.
Which is where the Hubble Space Telescope comes in because it's almost certainly a modified version of the basic KH-11 design. Though no official photos of the KH-11 satellites have been released, it's widely believed to bear more than a passing resemblance to the Hubble, with a long tube and a big curved mirror at its base to focus incoming light onto a CCD camera. When NASA was first designing the space telescope, they had originally planned on a mirror three meters across, but opted instead for one that 2.3 meters across to take advantage of mirror building machines built for spy satellites.