Courtesy USA-Today Charisse Jones April 26, 2011
Student question: Why use a carrier aircraft instead of launching a rocket directly into space?
Pam: It will save a considerable amount of fuel and energy, therefore reducing the cost of each flight and its ecological impact. Virgin Galactic has built a “green spaceship” with a remarkable low environmental footprint.
According to Virgin: "Every astronaut is an environmentalist,” implying that the very act of viewing the Earth from space will change people’s attitudes about pollution and the environment.
Virgin Galactic spacecraft is planning next year to take paying passengers ($200,000 per person with a $20,000 deposit). The craft is projected to be a six passenger, two pilot craft. Its planned trajectory will overlap the Earth’s atmosphere at 70,000 feet (21,000 m), which will make it a sub-orbital journey with a short period of weightlessness. The spacecraft, SpaceShipTwo, will be carried to about 16 kilometers or 52000 ft by a carrier aircraft, White Knight II. At that point, when the carrier aircraft reaches its maximum height, the SpaceShipTwo vehicle will separate and continue to over 100 km (the Kármán line, a common definition of where "space" begins). The time from liftoff of the White Knight booster carrying SpaceShipTwo until the touchdown of SpaceShipTwo after the sub-orbital flight will be about 3.5 hours. The sub-orbital flight itself will only be a small fraction of that time. The weightlessness will last approximately 6 minutes. Passengers will be able to release themselves from their seats during these 6 minutes and float around the cabin.