The exciting news of the day is that the “National Reconnaissance Office” is donating two unused spy satellites to NASA. From the limited information available, there are two satellites with 2.4 meter mirrors just sitting around gathering dust (metaphorically speaking, because they’re actually parked in a climactically controlled clean room). There are no instruments on board, and they lack solar panels or pointing controls, so it will take a fair bit of engineering to turn these into upward-looking space telescopes. In the real world, “engineering” is the same thing as “money”, so the exact fate of these satellites is not clear. However, it is likely that one will be repurposed into “WFIRST”, which was the Frankenstein-style mission proposed by the latest astronomical decadal survey to provide further observational constraints on Dark Energy. Many had wondered why no significant funding lines were opening up for WFIRST, but it seems likely that this has been the deep-background plan for a while. However, WFIRST is only one mission, and there are two satellites, which opens up some exciting possibilities. I’m sure the UV community in particular is starting to salivate — they’ve been making huge advances in coating and detector technology, so even a modest 2.4m mirror could offer as big a gain as the jump to the James Web Space Telescope (JWST) offers in the infrared.
As someone who spends a lot of time working with the Hubble Space Telescope, this is nothing but good news. The official lifespan of the Hubble is nominally over a few years from now, and the thought of losing generic optical-UV capabilities in space for a decade or more is horrifying. I’m now much more optimistic that we’ll at least have something up there while we do the hard work of figuring out how to move past the 2.4m aperture size.
The other interesting bit in this for many is the fact that this gift is coming from what is known as the “dark side” — the area of technological development that scientists are not allowed to know about. The same companies that build major space science facilities (Northrup-Grummond, Ball Aerospace, etc) also build facilities for the military and “reconnaissance” organizations. The science and military efforts are kept heavily firewalled from each other, of course, but there is frequently a very abstract, high-level of cross talk between the two. When you’re putting together a project, it becomes clear from the contractor which kinds of capabilities are “easy” (where “easy” means they know how to do it, because of requests from some other government entity). It is therefore no coincidence that both the Hubble Space Telescope and these unused satellites share a 2.4m mirror, and you can pretty much be assured that some of the expertise used in building JWST either came from or is destined to pass through to the dark side.