A small team in the Mojave Desert built the first privately funded crewed spacecraft to cross the boundary of space using a rocket motor that burned synthetic rubber with nitrous oxide and a reentry system modeled on a badminton shuttlecock. This episode explores Burt Rutan and Paul Allen’s Tier One program and the Ansari X Prize, which required a reusable vehicle to reach 100 kilometers twice within two weeks while replacing no more than 10 percent of its non-fuel weight. We look at why Allen spent roughly 25 million dollars chasing a 10 million dollar prize and why suborbital flight at Mach 3 demands about 60 times less energy than reaching orbit.

We break down the White Knight carrier aircraft that air-launched SpaceShipOne from 50,000 feet and doubled as an in-flight simulator, the hybrid engine that could not be throttled or steered once lit, the sea-level pressurized cabin with 16 small windows that let pilots fly without spacesuits, and the feathering wings that fold 70 degrees for a passively stable carefree reentry. Then we follow the flights: Brian Binnie’s first supersonic test on the Wright brothers’ centennial, Mike Melvill’s violent rolls on the June 2004 flight to space and again on flight 16P, and Binnie’s clean prize-winning flight to 112 kilometers on October 4, 2004.

• How air launch bypasses the densest atmosphere and shrinks the rocket needed
• Why a rubber and nitrous oxide hybrid motor is safer than liquid propellants but gives the pilot almost no control
• The physics of the shuttlecock: center of gravity forward, drag aft, and only about 14 pounds of thermal protection
• Roll excursions during boost and the cold gas thrusters Melvill used to recover
• Retirement to the National Air and Space Museum and the path to Virgin Galactic and SpaceShipTwo