Sam Dinkin, CEO of SpaceShot, the just-launched online game giving away rides to suborbital space as prizes, told me at the ISDC yesterday that his best customer has plunked down $500 in SpaceShot’s first month of operation. Space-Shot.com got 15,000 page views on launch day last month, representing 5,000 unique visits, said Dinkin.

Not bad for a venture awarding rides on a vehicle that has yet to fly, and a strong indicator of the tremendous potential demand for suborbital spaceflights among those not wealthy enough to buy $200,000 tickets outright. Dinkin’s identified a way to tap that market, essentially allowing those of ordinary means to pool their resources to send selected hopefuls among them into space.

The game costs $3.50 per play, which involves predicting the next day’s weather in Central Park. Predict better than others playing, and you advance through rounds of play, bringing you ever closer to a ride on the suborbital Rocketplane XP under development by Rocketplane Kistler. Dinkin has a deal with the company potentially worth hundreds of flights, including a guaranteed block of flights in the vehicle’s first six months of service.

Dinkin won’t tell me how much he paid Rocketplane to reserve those seats, but he’s hedging his bets; the money’s in escrow, and he can pull it and put it with another provider if Rocketplane doesn’t fly. Dinkin’s covering his customers too, as explained in the official rules:

“In the event that a given winner cannot participate in such a flight, through medical or other causes, or technical problems with the spacecraft, winners agree to accept the alternative prize of $150,000 instead. SpaceShot may revise this figure downward in $5,000 increments for new wins when a player receives the cash alternative prize.”

Nice.

Virgin Galactic‘s got a play-for-spaceflight plan too, but it hasn’t launched yet. In fact it seems somewhat…neglected, with its website promising that the games will begin “in Autumn 2005.”

Virgin and its spaceship contractor Scaled Composites have first-mover advantage in this space (literally), having launched the first commercial spaceship in 2004, but Rocketplane, along with SpaceShot, seem poised to catch up fast. And that competition can only be good for potential customers of both ventures.