NASA has long stated its aim of sending humans to Mars sometime in the 2030s.

But Donald Trump reportedly wanted it done much sooner.

In fact, an upcoming book by former White House communications official Cliff Sims says the president wanted the first manned spaceflight to the Red Planet done and dusted by the end of his first term in office ― 2020.

Sims details Trump’s fantastical attempt to bring the mission forward by more than a decade in Team Of Vipers, excerpts of which New York magazine published on Tuesday.

The author writes that Trump, before an April 2017 video call with U.S. astronaut Peggy Whitson, offered the space agency’s then-acting administrator Robert Lightfoot Jr. unlimited funds if NASA “focused entirely” on the mission to Mars “instead of whatever else you’re doing now.” Trump also promised to send NASA’s budget “through the roof.”

But the president was left “visibly disappointed,” Sims notes, when Lightfoot explained why it would not be possible.

CORRECTION: A previous version of this story misstated Peggy Whitson’s last name as Wilson.