Collapsible Rocket

Liquid Rockets are complex and have reliability problems due to their design. Liquid fuel and cryogenically cooled oxidizer need to be pumped super-fast using turbopumps. Turbo pumping heats the propellent which need to be cooled to improve the thrust. Therefore, I look alternative ways of eliminating the use of turbo pumps and cooling.

What if we could squeeze out the liquid propellent out of its container. For this idea to work, the walls of the rocket should have certain patterns. It should only collapse in one direction, vertical, not horizontal so that the aerodynamic shape of the rocket is not affected much. Carbon fiber would be woven inside the collapsible rocket walls to improve the strength.

While the rocket is in the launch pad, it would be supported from its upper section which would minimize the stress on the collapsible first stage. Because the liquids cannot be compressed and the tanks are full, the rocket would stay in its maximum height. Once the rocket is ignited, the propellent tanks would empty and the weight of the second stage and payload would squeeze the first stage. Coupled with the thrust coming from the bottom of the rocket, the propellent would be squeezed out and generate enough thrust. The rockets forward momentum would also push the propellent out, due to law of inertia, contributing to the thrust. The rocket doesn't need to be totally flattened out. The engine section would remain at its original dimensions.

After the first stage is released, it can deploy parachutes and recovered by the Catcher In The Fly, I had proposed earlier. The stage's engines can be reused but the collapsed casing would need to be recycled.

Super cool temperatures make the material brittle. Therefore, only RP-1 fuel can be used. The inner Liquid Oxygen (LOX) container which need to be collapsible as well would require a special alloy. If not found, nitrous oxide can be used which has a boiling point of -88 °C, much higher than oxygen.

Even though this idea may not work on the first stage, the second stage may utilize it.