NASA astronauts training for a possible mission to Mars have been practicing water maneuvers in a mock-up Orion space capsule in the Gulf of Mexico.
There's no doubt that NASA's timeline and plan to reach Mars is relatively aggressive, and now the space agency is admitting it might've been a bit too aggressive - at least with the current funding levels.
Mr Gerstenmaier's admission comes just days after Vice President Mike Pence said that the USA will "usher in a new era" of American space leadership, but budget cuts for Nasa from the Trump Administration seem to have taken its toll.
"The entry, descent and landing is a huge challenge for us for Mars".
At a meeting of the American Institute for Aeronautics and Astronautics, Nasa's chief of human spaceflight, William Gerstenmaier, said they can no longer commit to a date.
An Orion spacecraft is being prepared, at Johnson Space Center in nearby Houston, for flight atop NASA's as-yet-unflown megarocket, the SLS or Space Launch System. The US space agency, as a result, can not afford to start designing vehicles to land on Mars or ascend the surface, according to the report.
Fortunately, NASA isn't our only hope when it comes to a manned Mars mission - one of their contractors, SpaceX, is planning one.
Moreover, Elon Musks's SpaceX has also set a deadline of 2018 for an unmanned Mars mission and 2025 for a named mission.
Vice President Mike Pence had earlier hinted on "commercial space" - a kind of contracting NASA used to fund its commercial cargo and crew programs.
However, since NASA has the "support to extensive Moon surface program", Gerstenmaier opened the door to the possibility of landing humans on Moon again.
As a U.S. government organization funded by the taxpayers, one would think that NASA is one of the most well-funded bodies in the world.