Two More Steps to Space

by Courtesy Scaled Composites

Mojave, CA

4/18/2003

Legendary aviation designer Burt Rutan unveiled Friday what is probably the leading contender for a manned, commercial space-launch system. SpaceShipOne was revealed to the public at Rutan’s Scaled Composites headquarters in Mojave, California fully formed–a launch-ready prototype that will, within a few weeks, begin the series of tests that could send passengers into suborbital flight by early next year.

Rutan promises that his radical new system will be safe, reliable and, perhaps most importantly, cheap. The craft is one of the most innovative designs to contend for the X-Prize, a $10 million prize that will go to the first team to launch two passengers to a height of 100 km and safely return them to Earth–and then do it again within two weeks. If the chatter of the 300-person-plus crowd at Rutan’s unveiling on Friday is to be believed, it also marks the beginning of a new era in aviation.

SpaceShipOne looks much more like an airplane than a traditional rocket, with swooped-back vertical wings trailing a pointed cockpit. To launch, a specially built jet-powered airplane called the White Knight will carry SpaceShipOne to 50,000 feet and then drop the craft from its belly. Within seconds, SpaceShipOne will fire its single hybrid rocket engine

, which has been specially designed for the program–and shoot nearly straight up, at an angle of 84 degrees. The hybrid rocket is being developed by two competing third-party teams–Spacedev of San Diego, California., and EAC of Miami, Florida. Until Rutan’s company chooses a design, everyone is keeping quiet about engine specifications.

By the time the rockets have consumed their fuel, SpaceShipOne will have shot to an elevation more than 100 km–62 miles–above the surface of Earth (well above 99.9 percent of the atmosphere), and into sub-orbital flight. A pilot and two passengers will enjoy three or four minutes of weightlessness before gravity tugs the craft back down.

Now for the difficult part: reentry. Traditionally, there have been two dangerous strategies for returning a spacecraft to Earth: the high-speed, heat-intensive, straight-down drops such as those used in the Apollo program, and the precarious, controlled flights of the shuttle. Rutan has devised an ingenious third method for SpaceShipOne. During descent, the entire wing structure of the ship will tilt upwards about 70 degrees, making the entire craft look like a peacock lifting its tail. The wings control and guide the craft as it drops from space, while the fuselage acts as a giant air brake, slowing the ship’s descent. The drop is inherently stable, Rutan says: It doesn’t require precision maneuvering like the shuttle, and even though the ship hits Mach 3 on the way down (far slower than the Shuttle’s re-entry speed), the airbrake system eliminates the need for thick heat shields. At 80,000 feet, the wings return to a level position, and SpaceShipOne returns to Earth as a glider.

SpaceShipOne has not yet flown, but a space-ready prototype has been built, and flight-testing should begin soon. Rutan emphasizes the importance of his step-by-step testing program. As Popular Science‘s contributing aviation editor Bill Sweetman puts it, with other manned spaceflight test programs, “You either get into space, or you die.” (See “Space Shuttle: The Next Generation”, May 2003.)

SpaceShipOne should begin the first phase within a few weeks with simple drop tests: The White Knight mothership will release the spacecraft and let it glide back down to Earth. After a few unpowered flights, the team will release the spacecraft and, without pointing it into space, fire the hybrid rockets. Only when spacecraft and pilot control are full tested will Rutan’s team attempt a launch upwards into space. Rutan repeatedly refused to provide a timetable for the first flight but, given that the X-prize expires at the end of 2004, we can expect space-bound launches by this time next year, if not sooner.

Rutan is quiet on the matter of costs, though he said the $10 million dollar X-prize would not cover his program, and added that winning the X-prize is an “inspiration,” not his ultimate goal. He hopes, when his program is operational, to fly three people into space once a week for five months straight. Rutan added: “You might think of [SpaceShipOne] as a sub-scale, proof-of-concept spaceplane for a 10-person spaceship,” a craft better suited to a profitable space tourism business. Rutan also hopes that his craft will inspire a rush by designers and builders to create other space-planes; such a rush, he says, could lead to a renaissance in aviation design.