Stratolaunch

Air-launched orbital launch vehicle being developed by Paul Allen. 550,000 kg takeoff mass; 6,000 kg payload or Dragon reusable capsule to low earth orbit. Announced on 13 December 2011 with first flight scheduled for 2016.

The custom-built catamaran carrier air vehicle, designed by Burt Rutan, has a takeoff mass of 550,000 kg, a 117 m wingspan, and is powered by six 747-class turbofan engines. It can carrier the launch vehicle over a radius of 2400 km before dropping it for launch at an altitude of 9100 m, or ferry the empty vehicle or cargo over a maximum range of 17,000 km. It requires a 3700-m long runway for takeoff. The 220,000 kg, 37-m long SpaceX two-stage launch vehicle is a modification of the Falcon 9 with aft-mounted aerodynamic surfaces.