SpaceShipOne Flight 15P - Flight Profile

Flight Profile

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.

Taxiing for takeoff from Mojave Spaceport was originally planned for 06:30, because the wind conditions in that area are most favourable in the early morning. Taxiing actually started at 06:37, and the flight took off at 06:47. After an ascent to 47,000 feet (14.3 km) coupled with the White Knight airplane, the SpaceShipOne craft separated at 07:50 and immediately ignited its rocket.

Shortly after ignition, at about 60,000 feet (18 km), the craft unexpectedly rolled 90 degrees to the left, due to wind shear. When the pilot attempted to correct it, it rolled 90 degrees to the right. The pilot levelled the craft out, and proceeded with the climb. The correction of the roll excursion, using full trim, caused a pitch trim tab to run up against a stop. This caused the trim actuator, as designed, to stop operating for a 3 s timeout. Not realising what had happened, the pilot and controllers interpreted this as failure of the trim actuator, and they switched to a backup system. Spacecraft attitude was problematic during the entire climb, and not corrected until the start of re-entry.

During the burn, a new aerodynamic fairing installed around the rocket nozzle overheated, became too soft, and crumpled inwards. This caused a loud bang, which the pilot reported, but did not cause a flight problem.

The rocket burn lasted for 76 seconds. At burn-out the altitude was 180,000 feet (54.9 km), the Mach number was 2.9, and the speed was 2150 mph (3460 km/h; 961 m/s).

The planned apogee altitude was 360,000 feet (110 km), but due to the attitude problem encountered during the climb the craft actually attained only 328,491 feet (100,124 m). In doing so it passed the boundary to space at 100 km, making the flight, as planned, officially a spaceflight. It can be calculated that the altitude exceeded 100 km for approximately 10.23 s.

Around apogee the craft experienced about 31⁄₂ minutes of weightlessness. Pilot Mike Melvill opened a bag of M&M's and watched them float around the capsule in free-fall.

The craft re-entered the atmosphere 22 miles (35 km) south of its planned 5 by 5 mile (8 by 8 km) re-entry zone. The pilot finally corrected the spacecraft attitude at this point, using a backup trim system. The craft reached Mach 2.9 and experienced deceleration of 5.0 g (49 m/s²) during descent. The craft switched to gliding configuration at an altitude of 57,000 feet (17.4 km), then returned to the spaceport and landed safely at 08:14.