Never mind Formula One -- let's race rockets!

Motor racing is taking to the sky.

The aerospace junkies behind the Ansari X Prize, a $10m flight contest, on Monday introduced the Rocket Racing League (RRL), an organisation to host and run rocket competitions throughout the US.

Peter Diamandis, co-founder of the RRL, called it the next-generation racing industry: "The Rocket Racing League will inspire people of all ages to once again look up into the sky to find inspiration and excitement."

A debut exhibition race is planned for the X Prize Cup in September 2006. In the six months after that, the league expects to see races at an additional two air shows and two car racing events, with a championship event in New Mexico at the 2007 edition of the X Prize Cup.

The events will take a leaf from motor racing's book.

Rocket planes called X-Racers will compete on a sky 'track' in the design of a Grand Prix race, with long straights and the added dimenson of vertical ascents and deep banks. The race will run perpendicular to spectators and be about two miles long, one mile wide and 1,500m in the air. The X-Racers will be staggered upon take-off and fly their own 'tunnel' of space, each separated by a hundred metres or so.

Pilots will be guided by differential GPS (Global Positioning System) technology to help them avoid collisions.

A prototype of the X-Racer, being built in partnership with California-based XCOR Aerospace, will be flown this weekend at the X Prize Cup 2005 in Las Cruces, New Mexico. The X-Racer rocket is modelled on XCOR's EZ-Rocket, but the next version will draw from the airframe of Florida-based Velocity.

Retired US Air Force Colonel Rick Searfoss, a former commander of the space shuttle Columbia, will fly the rocket.

The venture has its eye on marketing the races as entertainment. The races will be open to the public around the US, and by the third year of racing, the league expects that one out of three venues will be outside the country.

RRL plans to introduce a videogame based on the competitions in late 2007.

Diamandis founded the X Prize, an annual contest promoting personalised space flight. In October 2004, the contest made history when the SpaceShipOne craft, backed by Microsoft co-founder Paul Allen, sped 100km above the Earth's surface and then landed safely in the Mojave desert twice in less than a week.