It's a Rocket! It's a Plane! It's...Rocket Plane!

But Dan Erwin, an associate professor of astronautics at the University of Southern California, feels that Rocketplane just might have the magic numbers. â€I think this is actually doable,†he says. â€The mass, thrust, volume-all that stuff I figure can work.†Erwin sees the rocket engine as the biggest hurdle. â€There are no show-stoppers in principle,†he says of developing a new rocket safe enough for manned flight, â€but there is an awful lot of elbow grease that has to be laid on the problem.â€

Blastoff

That task falls to David Crisalli, head of engine contractor Polaris Propulsion. Before starting his company in Oxnard, California, in 1997, Crisalli was an engineer with top rocket maker Rocketdyne. His customers now include Boeing, Northrop Grumman and Rocketdyne. Crisalli took on the project with the assurance that Rocketplane wasn´t about to cut corners on safety to meet its schedule and budget. â€There´s a difference between thinking out of the box and being out of your mind,†he says.

Satisfied that Rocketplane fit into the former category, Crisalli brought a group of Apollo-era NASA contractors out of retirement to help him develop a regeneratively cooled (that is, cooled by circulating propellant) rocket engine that can be used over and over again like a jet engine. Polaris completed preliminary design work on Rocketplane´s AR-36 in April and then went to work building it. It´s on schedule for the Rocketplane XP´s first rocket-powered test flights in 2008, after jet-engine-only test flights begin at the end of 2007.

French won´t say how much it will cost to develop and operate the Rocketplane, or when he´ll recoup his investment. But he and his engineers see suborbital space tourism as merely the start of an ever-expanding market that will eventually include same-day global package delivery and ultrafast intercontinental travel. With the Kistler acquisition, French expects to operate flights to orbit for both government astronauts and space tourists visiting commercial space stations.

But first they´ll need a successful debut. Anderson is ready to go.

Michael Belfiore´s book The Entreprenauts: Visionaries and Daredevils of the New Space Age is forthcoming from Smithsonian Books/HarperCollins.