When space tourist Dennis Tito returns to Earth on Sunday, plenty of others will be lined up to take his place. 

Arlington-based Space Adventures, which helped Tito broker the reported $20 million deal to buy a ride on a Russian spacecraft, says it has several serious customers willing to pay tens of millions of dollars for a trip into outer space. 

Moreover, the company has already booked 100 reservations for a $98,000 suborbital space flight aboard a "space business jet" that hasn't even been built. Space Adventures declined to release potential space tourists' names. 

Space Adventures President and Chief Executive Eric Anderson said Tito's weeklong visit to the International Space Station and flight aboard a Russian Soyuz rocket has piqued interest in the fledgling space tourism industry. 

When the movie 2001: A Space Odyssey came out in 1968, "people envisioned that flights in space would be routine by now," Anderson said. "When people really think about it, they realize this is long overdue." 

NASA, which opposed Tito's visit to the space station and demanded he sign waivers agreeing to pay for anything he breaks, says it has no plans to let civilians buy flights on its space shuttles. 

It has, however, worked with its other international partners to develop procedures for future civilian visits to the space station, said NASA spokeswoman Debra Rahn. Those protocols, pushed forward because of Tito's deal, should be in place by the end of June. 

Tito "just flew a little earlier than the partners had anticipated," Rahn said. 

For now, the bulk of Space Adventures' effort is directed toward what it hopes can be a more affordable space adventure: suborbital space flight, the type pioneering astronaut Alan Shepard took for the first time exactly 40 years ago, on May 5, 1961. 

Space Adventures' goal is to have the first tourists flying by 2005. 

More than a dozen companies are working on a "space plane" that could make such a trip. 

Anderson envisions a craft that would carry three to six tourists 100 kilometers up in the air, the accepted definition of a space flight. Passengers could experience three or four minutes of weightlessness and be able to look down on almost 3,000 miles of Earth's surface — enough to take in the outline of North America's East Coast. 

Such a flight could require only four days of training, compared with the six months Tito underwent, Anderson said. 

So far, 100 people and corporations have paid roughly $2 million in deposits, most it refundable, to get a spot on the first flights. The company plans to hold an auction among reservation holders to determine the order. 

"We're engineers, so we never say 100 percent. But it would be highly unlikely that this won't come about," company Vice President Larry Ortega said. 

Bob Haltermann, executive director of the Arlington-based Space Transportation Association's tourism division, a nonprofit group that lobbies on behalf of space tourism, suggested that one of the seven seats on a space shuttle could be opened to the public through a lottery that could help NASA raise millions of needed dollars. 

"NASA is a very exclusive group of people, and they have a problem with wanting to keep it that way," Haltermann said. 

Tito, 60, said that when he returns to Earth, one of his first jobs will be trying to get NASA to embrace his idea that space is for everyone. 

"I am enjoying this so much," Tito said Friday. "If I were allowed, I would spend several months up here in space."