Bass, who already has passed a battery of medical tests and has begun flight training, wants to buy a ride to the station from the Russians and create an eight-episode reality TV program chronicling his journey.
But while a television producer working with Bass said Wednesday that a contract had been signed with the Russians -- and that a major television network is in negotiations to help sponsor the trip -- there are still a number of hurdles to clear before the 'N Sync member can become the world's third space tourist.
First, the National Aeronautics and Space Administration and the other station partners must agree to let Bass take the trip.
Then there is the estimated $20 million price tag, which Bass boosters hope will be covered by sponsors eager to tap into the young audience that Bass is almost certain to attract.
David Krieff, president of Destiny Productions and the primary backer of the plan to launch Bass, said he expects an easy ride from here.
"We're all drinking champagne here today," said Krieff, who declined to identify the network involved in the discussions, although some online reports suggest it is MTV.
"We've already got great sponsorship opportunities," he said. "I'm excited about it, and I think it's a great opportunity. I'm thrilled we've come this far."
A representative of MirCorp, the Dutch space-tourism company working with Bass, could not be reached Wednesday.
Only a few months ago, the Russians were insisting that Bass was not a candidate to join two cosmonauts on a 10-day mission aboard the Soyuz craft in October.
But in the letter to NASA, the head of the Russian spaceflight directorate describes Bass' trip as crucial to the cash-strapped program.
Mikhail V. Sinelschikov asked for the cooperation of NASA and other international partners in approving Bass, even though the crew-selection guidelines agreed to earlier this year by the partnership require that names be submitted at least six months in advance of a flight.
The letter implies that without the estimated $20 million infusion from the Bass trip, the Russians won't be able to meet their obligations to the station project.
"Extenuating circumstances regarding funding forces us to come up with this late nomination," Sinelschikov wrote.
The letter goes on to say that Bass' inability to speak Russian should not be a problem, because the two cosmonauts assigned to travel with him are both fluent in English.
In addition, Sinelschikov wrote, the flight activities will be tailored to jibe with Bass' shortened training schedule.
While NASA has not opposed Bass' trip, spokesman Bob Jacobs said it would be premature to speculate about whether he would be cleared to fly by the partnership because the Russians had not yet formally presented his nomination.
"This is not just a NASA-Russia thing," he said.
The administrators who will make the decision are not scheduled to meet until September, although they could huddle before that, Jacobs said.
The rule requiring the partners to sign off on any nonastronaut headed to the station emerged from the controversy surrounding the May 2001 flight of California businessman Dennis Tito, the pioneering space tourist. NASA and the Russian space agency battled for months about Tito's flight, and the partners wanted to make sure that they had some control over who travels to the station.
In late April, South African Internet magnate Mark Shuttleworth became the second tourist to ride a Soyuz to the space station. NASA didn't fight his selection and allowed Shuttleworth and his two Russian crewmates to train on a station mockup at Johnson Space Center in Houston.
Bass, 23, spent a week in seventh grade at Space Camp at Kennedy Space Center. In biographies aimed at the band's young female fans, Bass lists "astronaut" as his childhood ambition and says he yearned to fly after his experience at the camp. Instead, he rocketed to fame as a member of the wildly popular five-person band.
Among the things that could disqualify a "spaceflight participant" such as Bass are "notoriously disgraceful" conduct, habitual drunkenness and drug use. Musical taste or talent is not addressed.
Krieff, who is working with the William Morris talent agency to sign up sponsors -- Radio Shack has been on board for a couple of months -- said he does not anticipate any problems with either the international partners or the money.
He did acknowledge, however, that former NASA official Lori Garver, who has dubbed herself "AstroMom" and has done some training alongside Bass, is the official backup if plans for the singer fall through.
If Bass does go, Krieff envisions a one-time series, somewhat modeled on MTV's hit The Osbournes, that would track Bass during his flight.
"It's going to be an unbelievably captivating program," he said. "And one that really has, in my opinion, real relevance in terms of Russia and America forming a peaceful union to send a kid from 'N Sync into space."