The US solid rocket manufacturer ATK has received a contract from Orbital Sciences Corporation to provide first and second stage propulsion for the Air Launch Vehicle (ALV) that Orbital Sciences is designing and building for Stratolaunch Systems Corporation. ATK has extensive experience in building large diameter solid rocket engines including the Solid Rocket boosters of the Space Shuttle.
Comment by David Todd: While the the air-launched Stratolaunch main rocket launch system will use cheaper-to-produce high thrust (if less efficient) solid rocket engines for its first two stages, unlike its Pegasus air launched predecessor, it will also employ a high energy liquid fuelled upper stage to ensure that it can carry enough payload accurately into orbit. This configuration, designed by Orbital Sciences, is very similar to the solid-solid-liquid stage formulation of Europe’s next ground launched rocket: the Ariane 6.
