Assuming the 500-mph, mile-long flight through the Mojave Desert does not kill him, Mike Hughes told the Associated Press, his journey into the atmosflat will mark the first phase of his ambitious flat-Earth space program.
Hughes's ultimate goal is a subsequent launch that puts him miles above the Earth, where the 61-year-old limousine driver hopes to photograph proof of the disc we all live on.
"It'll shut the door on this ball earth," Hughes said in a fundraising interview with a flat-Earth group for Saturday's flight, which ranged across theories that NASA is controlled by round-Earth Freemasons, and Elon Musk makes fake rockets from blimps.
Hughes promised the flat Earth community to expose the conspiracy with his steam-powered rocket, which will launch from a heavily modified mobile home - though he acknowledged that he still had much to learn about rocket science.
"This whole tech thing," he said in the June interview. "I'm really behind the eight ball."
That said, Hughes isn't a totally unproven engineer. He set a Guinness World Record in 2002 for a limousine jump, according to Ars Technica, and has been building rockets for years, albeit with mixed results.
"Okay, Waldo. 3 . . . 2 . . . 1 . . .!" someone yells in a test fire video from 2012.
There's a brief hiss of boiling water, then . . . nothing. So Hughes walks up to the engine and pokes it with a stick, at which point a thick cloud of steam belches out toward the camera.
He built his first manned rocket in 2014, the AP reported, and managed to fly a quarter mile over Winkelman, Arizona.
As seen in a YouTube video, the flight ended with Hughes being dragged, moaning from the remains of the rocket. The injuries he suffered put him in a walker for two weeks, he said.
And the 2014 flight was only a quarter of the distance of Saturday's mile-long attempt.
And it was based on round-earth technology.
Hughes only recently converted to flat-Eartherism, after struggling for months to raise funds for his follow-up flight over the Mojave.
It was originally scheduled for early 2016 in a Kickstarter campaign - "From Garage to Outer Space!" - that mentioned nothing about illuminati astronauts, and was themed after a NASCAR event.
"We want to do this and basically thumb our noses at all these billionaires trying to do this," Hughes said, standing in his Apple Valley, California, living room, which he had plastered with drawings of his rockets.
"They have not put a man in space yet," Hughes said. "There are 20 different space agencies here in America, and I'm the last person that's put a man in a rocket and launched it."
He compared himself to Evel Knievel, as he promised to launch himself from a California racetrack - the first step on his steam-powered leap toward space.
Hughes made other pitches, including a plan to fly over Texas in a "SkyLimo." But he complained to Ars Technica last year about the difficulty of funding his dreams on a chauffeur's meager salary.
A year later, he called into a flat-earth community web show to announce he had become a recent convert.
"We were kind of looking for a new sponsors for this. And I'm a believer in the flat Earth," Hughes said. "I researched it for several months."
The host sounded impressed. Hughes had actually flown in a rocket, he noted, whereas astronauts were merely paid actors performing in front of a CGI globe.
"John Glenn and Neil Armstrong are Freemasons," Hughes agreed. "Once you understand that, you understand the roots of the deception."
The host talked of "Elon Musk's fake reality," and Hughes talked of "anti-Christ, Illuminati stuff." After half an hour of this, the host told his 300-some listeners to back Hughes's exploration of space.
While there is not single hypothesis for what the flat Earth is supposed to look like, many believers envision a flat disc ringed by sea ice, which naturally holds the oceans in.
What's beyond the sea ice, if anything, remains to be discovered.
"We need an individual who's not compromised by the government," the host told Hughes. "And you could be that man."
A flat-Earth GoFundMe subsequently raised nearly $8,000 for Hughes.
By November, the AP reported, his $20,000 rocket had a fancy coat of Rust-Oleum paint and "RESEARCH FLAT EARTH" inscribed on the side.
While his flat-Earth friends helped him finally get the thing built, the AP reported, Hughes will be making adjustments right up to Saturday's launch.
He won't be able to test the rocket before he climbs inside and attempts to steam himself at 500 mph across a mile of desert air. And even if it's a success, he's promised his backers an even riskier launch within the next year, into the space above the disc.
"It's scary as hell," Hughes told the AP. "But none of us are getting out of this world alive."
This is true. Yet some may dare to fly beyond its edge.