NASA has begun surveying scientists on what they would like to do with two Hubble-class space telescopes donated to the civilian space agency by its secretive sibling, the National Reconnaissance Office (NRO) -- which operates the nation's spy satellites.
But the gifts have some formidable strings attached, including costs to develop instruments and launch the observatories. The telescopes, though declassified, also are subject to export regulations.
"We need to retain possession and control," NASA's astrophysics division director Paul Hertz told Discovery News. "That doesn't preclude us from partnering (with other countries). It just sets boundaries on the nature of the partnership."
NASA also isn't allowed to use the telescopes for any Earth-observing missions.
Topping the list of possible missions for the donor hardware is a remake of NASA's planned Wide-Field Infrared Survey Telescope, known as WFIRST. The mission, estimated to cost between $1.5 billion and $2 billion, is intended to answer questions about dark energy, a relatively recently discovered phenomenon that is believed to be speeding up the universe's rate of expansion.
WFIRST is the National Academy of Sciences' top-ranked, large space mission for astrophysics.
NASA, however, is prohibited from starting a new major astrophysics initiative until development costs for the overbudget James Webb Space Telescope, the follow-on to the Hubble observatory, ramp down.
NASA has not yet determined how using the NRO's larger telescope -- the primary mirror is 2.4 meters in diameter, compared to WFIRST's proposed 1.3-meter mirror -- would impact the mission's goals or costs.
"One advantage it might make using these would be if it gives us a WFIRST with more capability and the capability to do the science better, or faster, or more science. There's a whole lot of ways that a larger telescope might benefit you, even if it doesn't save you money," Hertz said.
This week, NASA plans to issue a solicitation for additional proposals for using the NRO telescopes.
"We're hoping that that there are people out there who think of things that are really interesting that we haven't thought of," Hertz said.
Looking beyond the astrophysics community also might give NASA some budget leeway.
"The rest of the agency has potentially more flexibility," said Michael Moore, NASA's assistant director for innovation and technology.
"There are interesting things you can do for other reasons that wouldn't be science-driven necessarily," such as robotics, Moore told Discovery News.
Besides astrophysics, the observatories could be used to study extra-solar planets or the heliosphere, the region of space under the sun's influence.
Proposals are due Jan. 7 and a follow-up workshop is planned for February.