Dennis Tito wants to send two astronauts to Mars as soon as Christmas 2017, but NASA — from whom Tito's non-profit Inspiration Mars organization needs $700 million in funding — has snubbed the American billionaire. In an email statement sent to Inspiration Mars, NASA's David Weaver said "the agency is willing to share technical and programmatic expertise with Inspiration Mars, but is unable to commit to sharing expenses with them."

In addition to financial assistance, the billionaire needs to use NASA's Space Launch System (SLS) to power his organization's planned mission — technology still under development, and funded by the federal government. Weaver also says Tito's aim of getting humans to Mars in the planned time-frame is unrealistic. "Inspiration Mars' proposed schedule is a significant challenge due to life support systems, space radiation response, habitats, and the human psychology of being in a small spacecraft for over 500 days." Tito's organization is pushing for a manned mission to launch between Christmas 2017 and January 5th, 2018, to take advantage of planetary positioning to make the distance between Earth and Mars shorter. The next window of opportunity for such an alignment will reportedly occur in 2021.

NASA's own schedule puts a manned mission to Mars somewhere in the 2030s. That slower pace — understandable in an agency that recently had its web presence turned off by a government shutdown — was hinted at in October when the space agency released a cautious statement reiterating that it had "not made any commitments to Inspiration Mars related to launch vehicles." Although Weaver says NASA remains "open to further collaboration as their proposal and plans for a later mission develop," don't expect Inspiration Mars to be taking humans to the red planet this decade.