Stage Zero Revisited

In my first book, I had proposed stage zero for a space rocket. After many design iterations, I am revisiting the idea again. This stage can easily be developed with current technologies. However, the stage is considered as a plane and therefore it is never build. However, it should be treated as a rocket with wings that flies at denser atmosphere.

It would run with the same fuel as the rocket itself. The oxidizer would be LOX. There are several options for its engine. It can be either a ramjet with LOX injectors or a simplified version of the rocket engine with high bypass enclosure. Designing a ramjet is much easier than a classical turbofan engine or a rocket engine. However, lower thrust would require more of these engines and larger propellant tanks. Unlike classical rockets, the atmosphere would be utilized during propulsion. It wouldn’t be as efficient as a turbofan engine, but would have much higher efficiency compared to a rocket engine. These engines will be supported by two wings, one at the top and one at the bottom. Multi-wings increase the lift of the stage zero and increases the strength of the engine housing. These wings together with the engines will be 90 degrees rotatable. This increases the thrust for takeoff and eliminates the need for ailerons. Stage zero will not fly at supersonic speeds. It will just climb. At higher altitudes more and more LOX will be used. Ambient heated air will provide additional thrust.

Stage zero would vertically takeoff and climb on a spiral route to the deployment altitude. The rocket would be housed inside a fairing to improve aerodynamics. At the deployment altitude, these fairings would open and the rocket would be released and fired. The objective of this stage is to launch the rocket at a much higher altitude. Therefore, the rocket wouldn’t need aerodynamic design details (no payload fairing) and all the engines can be vacuum optimized.

Companies have previously tried to launch a rocket from a plane. However, they are by no means close to my proposal. I propose a completely specialized rocket plane. Which is considerably different compared to a traditional cargo plane. It has multi-wings and special engines and the rocket is enclosed inside. Therefore, it should be mainly designed by rocket designers with collaboration with aeronautical engineers. Designing such stage would be much easier than designing a large first stage of a rocket. Additionally, this stage would consume less fuel compared to a rocket while it would have wings to support lift and high bypass engines for improved fuel consumption. Recovering stage zero would also be much easier due its wings compared to a very tall and thin first stage of a rocket. Finally, the rocket utilizing stage zero wouldn't need a launch platform. Horizontally assembled rocket can be launched horizontally.