Imagine you had a Hubble-class telescope and could use in any way you wanted to explore planets. What would you do with it?

A number of scientists have had the chance to explore that question courtesy of an American spy agency. A year ago, NASA received a surprise phone call from the National Reconnaissance Agency (NRO), which flies spy satellites, asking if it would like two spare, Hubble-class space telescopes. NASA’s managers said,”Yes!,” and now the agency is looking for the best uses for the telescopes. The highest priority is to see if one telescope could be used to meet the needs for the Wide-Field Infrared Survey Telescope (WFIRST) to study dark energy. That potentially leaves a second telescope for other deep space or solar system studies.

Before I describe the concepts discussed at a recent conference, a truth in advertising statement is required. Each telescope represents $250M worth of hardware. However, not all the systems needed for an actual satellite are included, instruments are not included, and the whole lot would need to be launched. Figures I’ve read suggest that turning each telescope into a working observatory would cost approximately $1B, depending on the specifics of the mission. NASA’s current budgets have no room to fund a single mission, much less two. In a few years, there may be room for a mission or two, so the space agency is soliciting ideas.