Multimillionaire Dennis Tito revealed the details for his proposed manned flyby mission to Mars, which included a request for millions of dollars from NASA.

According to the Wall Street Journal, Tito appeared before a House of Representatives science subcommittee Wednesday to explain the details of his proposal. The Inspiration Mars mission, as it is called would take two astronauts on a flyby of Mars in 2018. He acknowledged the low likelihood of being granted federal money for the mission and said he also has a plan to launch in 2021.

He did not specify exactly how much the mission would cost or how much he would need from NASA, but outlined the mission's potential political significance and technological details.

"Perhaps several hundred million dollars in new federal spending can make this mission happen," Inspiration Mars officials wrote in a report, released Wednesday. "We now call on our nation's leaders to seize this singular opportunity to begin human exploration of the solar system and affirm America's leadership throughout the world."

He said the manned mission to Mars would "[win] back the world's attention" and is a "grand and worthy goal." He also said his proposal is a model for other private space companies looking to partner with NASA.

Tito said the federal funding would have to come within the next couple months to meet the 2018 deadline. He said the project on the whole will be "less than $1 billion" above current NASA spending levels. Tito also plans to raise $300 million of philanthropic money over the next five years.

"So far the fundraising has been pretty much out of my pocket," he said. "I don't have any assurances except my... stubbornness not to give up."

Rep. Dana Rohrbacher, a California Republican and advocate for private funding for space missions, told Tito he did find it likely. Private space companies are often faced with a difficult challenge when asking for federal money.

"I don't know if we can get it done," Rohrbacher said.

NASA and the Obama administration have plans to send humans to Mars, but not until around 2030. If Inspiration Mars can get off the ground by 2021, it could lay the groundwork for those future missions.

"There'll be a lot of science return and technology return," Taber MacCallum, Inspiration Mars' chief technology officer, told Sapce.com and other reporters Wednesday. "We will, I think, sort of break the sound barrier for going to Mars and back, enabling a range of missions to occur in the future."