Burt Rutan's Ansari SpaceShipOne performs a successful spaceflight, the first of two required to win the Ansari X Prize.

Elbert Leander "Burt" Rutan is a retired American aerospace engineer and entrepreneur noted for his originality in designing light, strong, unusual-looking, and energy-efficient air and space craft. He designed the record-breaking Voyager, which in 1986 was the first plane to fly around the world without stopping or refueling. He also designed the Virgin Atlantic GlobalFlyer, which in 2006 set the world record for the fastest and longest nonstop non-refueled circumnavigation flight in history. In 2004, Rutan's sub-orbital spaceplane design SpaceShipOne became the first privately funded spacecraft to enter the realm of space, winning the Ansari X-Prize that year for achieving the feat twice within a two-week period.

SpaceShipOne is an experimental air-launched rocket-powered aircraft with sub-orbital spaceflight capability at speeds of up to 3,000 ft/s (2,000 mph) / 910 m/s (3,300 km/h) using a hybrid rocket motor. The design features a unique "feathering" atmospheric reentry system where the rear half of the wing and the twin tail booms folds 70 degrees upward along a hinge running the length of the wing; this increases drag while retaining stability. SpaceShipOne completed the first crewed private spaceflight in 2004. That same year, it won the US$10 million Ansari X Prize and was immediately retired from active service. Its mother ship was named "White Knight". Both craft were developed and flown by Mojave Aerospace Ventures, which was a joint venture between Paul Allen and Scaled Composites, Burt Rutan's aviation company. Allen provided the funding of approximately US$25 million.

The Ansari X Prize was a space competition in which the X Prize Foundation offered a US$10,000,000 prize for the first non-government organization to launch a reusable crewed spacecraft into space twice within two weeks. It was modeled after early 20th-century aviation prizes, and aimed to spur development of low-cost spaceflight.