Commercial space entrepreneurs are developing rockets that will take tourists to the moon in the not-too-distant future. But a software maker has taken a head start on the adventure by simulating a lunar ride for the PC user.

Virtue Arts, based in Los Angeles, has developed software that renders the exact physics and topology of the moon in a 3D game, letting players drive over the lunar surface, gaze at the galaxy or study objects that were left by NASA astronauts on real missions.

Lunar Explorer uses NASA data on the topology and physics of the moon that lets kids and adults explore the lunar surface.

NASA Ames plans to use the software to engineer space vehicles and train astronauts for future missions.

"This revolutionizes the use of visualization technology - it brings it down to everyone's computer, " Mary Duda, founder and CEO of Virtue Arts, said in an interview.

Jerome Rasky, the 10-year-old son of a NASA scientist, tested a game version of the software, called Lunar Racing Championship at NASA's Exploration Center. He said it's not as easy as it looks.

"It's like someone put a jet on your car and you have to control it, " Rasky said. "I've played car games before but nothing like this."

Virtue Arts engineered its game and moon-exploration software with publicly available data that NASA and other international space agencies have collected from missions to the moon. That way, the software draws on real science to encourage play and learning, according to Duda.

For example, the moon's gravity is one-sixth of the Earth's, so driving among its rocks and on its dusty surface is more weightless and out of control than driving on Earth. Aerodynamics are meaningless on the moon, so the lunar buggy in Virtue's Lunar Racing Championship software includes rocket boosters and a reaction control system, which is typically found on spacecraft, to stabilize itself in the event of spinning out of control. But speeds of only 8 miles per hour can cause a dust storm because of the moon's fine surface.

The lunar software also includes exact renderings of the constellations, the Earth, the Sun and the galaxies.

Virtue Arts developed a system called RADE, or rapid application development environment, so that it can process the lunar data in real time on a consumer PC. It's a tall order, according to Virtue Arts Chief Technology Officer Romesh Prakashpalan, because the application must process a data source of 10 gigabytes, an amount that's typically been the domain of high-end servers.

The Lunar Racing Championship application is also networked so that, for example, two kids can race each other in the game from two different PCs.

The Lunar Racing Championship game is expected to be released to consumers next June for $49.95. Lunar Explorer is currently available for $39.95. Both applications can run on a standard consumer-grade PC with a graphics accelerator.

Obviously, NASA plans to use the software for a higher purpose.

"We need to simulate space for designing vehicles and missions because there are a lot of complicated questions to answer in the process, " said Dan Rasky, a senior scientist at NASA.