SpaceShipOne Flight 16P - Flight Profile

Flight Profile

The SpaceShipOne pilot was Mike Melvill. There were three chase planes.

All times are in PDT, which is seven hours behind UTC. This was the local civil time at the spaceport on the day of the flight. All measurements are first stated in the U.S. customary units in which they were originally reported, with conversions to SI units also given.

The flight was planned to take off from Mojave Spaceport in the early morning, when wind conditions are most favourable. Takeoff was scheduled for 06:47, but was delayed because of winds gusting to 50 mph (20 m/s), which subsided after sunrise. White Knight, carrying SpaceShipOne, taxied to the runway at 07:00, and took off at 07:11.

After takeoff, White Knight and SpaceShipOne ascended to the launch altitude, planned to be around 14 km. At 08:09 SpaceShipOne was released, glided for 6 s, then went into nose-up attitude and the rocket motor was ignited. The rocket motor was capable of burning for approximately 87 s, having been upgraded since the previous flight. It was planned to shut off the motor at an altitude of 345,000 feet (105 km), presumably to avoid pushing the envelope too far.

The spacecraft started rolling rapidly 50 s into the burn, while travelling at Mach 2.7. This was probably due to, or at least exacerbated by, pilot error. The pilot was not highly concerned by this, being confident that he could correct the situation, and he allowed the burn to continue during the roll. He later said "I thought it was kind of cool". The altitude was too high (and thus the atmosphere too thin) for the roll to cause significant aerodynamic stress, and it was correspondingly infeasible to damp the roll rate using the aerodynamic control surfaces.

When there was sufficient velocity to assure the achievement of the target altitude, as predicted by the navigational system, the ground controllers recommended that the pilot abort the burn. He promptly did so, 76 s into the burn, cutting it short by 11 s. After engine cutoff, the craft continued climbing while rolling. The pilot did not immediately work to damp the roll. Around apogee he took photographs of the Earth using a digital still camera.

The apogee altitude was estimated by the nearby Edwards Air Force Base, based on radar data, to be 337,569 feet (102.9 km). Due to the early burn cutoff, this was far less than originally anticipated. However, it was more than the 100 km necessary to qualify as a spaceflight and satisfy X PRIZE requirements. Early reports said that after the instruction from the ground the pilot had delayed the burn cutoff in order to exceed 100 km; in fact the instruction was issued just after the 100 km altitude was assured, and the pilot's reaction time accounts for the additional 2.9 km.

After apogee, the pilot feathered the wing for atmospheric reentry. He then damped out the roll, without difficulty, using the reaction jets. Overall, the craft did 29 complete rolls. Atmospheric reentry proceeded normally, with the craft rapidly righting its attitude due to the stable high-drag configuration. It changed back to gliding configuration normally, glided back to the spaceport, and landed safely at 08:34. White Knight then landed at 08:39.