Stratolaunch / Thunderbolt

Thunderbolt with Roc carrier plane [Stratolaunch]

Stratolaunch is a consortium consisting of Scaled Composites and Orbital to build an air-launched rocket system called Eagles to provide orbital access for medium payloads to space with greater safety, cost-effectiveness and flexibility.

Scaled Composites will provide the six engined carrier aircraft Roc built from parts of two Boeing B-747.

SpaceX was originally the partner to develop the launch vehicle based on the Falcon-9 rocket. In November 2012 SpaceX dropped out of the project and was replaced by Orbital Sciences, who will design a launch vehicle. Dynetics, which was to provide the mating and integration system allowing the carrier aircraft to safely carry the booster also dropped out.

The Thunderbolt rocket, initially known as "Pegasus-2" consists of two ATK built solid-fuel stages and a restartable crogenic upper stage. The first two stages will have a Thrust Vector Control (TVC) system. The upper stage will be initially powered by two RL10C-1 engines for low earth orbit missions or by one RL10 for GTO missions.

In May 2015, Stratolaunch announced, that the Thunderbolt rocket is economically not feasable and that they are going to evaluate over 70 other launch vehicle variants.

In early 2019 it was announced, that Stratolaunch dropped plans to develop a launch vehicle of its own. The carrier plane will be used for launching the Northrop Grumman Pegasus-XL rocket. Stratolaunch ended operations at the end of May 2019 and Pegasus launchers planned to fly with their Roc carrier plane will be repurposed for the standard L-1011 carrier plane.