NYTimes: The phone call came like a bolt out of the blue, so to speak, in January 2011. On the other end of the line was someone from the National Reconnaissance Office, which operates the nation’s fleet of spy satellites. They had some spare, unused “hardware” to get rid of. Was NASA interested?
... Sitting in a clean room in upstate New York were a pair of telescopes the same size as the famed Hubble Space Telescope, but which had been built to point down at the Earth, instead of up at the heavens.
... to turn one of the telescopes loose on the cosmos, pointing in its rightful direction, outward, to investigate the mysterious dark energy that is speeding up the expansion of the universe. If the plan succeeds — and Congress, the Office of Management and Budget and the Academy of Sciences have yet to sign on — it could shave hundreds of millions of dollars and several years off a quest that many scientists say is the most fundamental of our time and that NASA had said it could not undertake until 2024 at the earliest.