Low Cost Rocket

Current trend for rocketry is towards reusability which makes sense in most cases. However, if a country is only planning to make several launches a year. It would be quite expensive to develop and operate reusable rockets. I thought of alternatives for a low cost rocket. Not all bottles are made of glass that can last for centuries. We also have plastic ones for single use.

After making some research on the subject I found out that single use materials actually would not be that cheap for a rocket. For example, the cascaded cryogenic propellent tanks of the rocket can be made of PTFE. However, PTFE is not that cheap. On the other hand, cheap polyethylene is brittle at low temperatures. At least I came up with some design changes to the engine of the rocket which would reduce the costs a little.

Powerful rocket engine requires bigger combustion chamber. However, larger inner volume would reduce combustion efficiency and the fuel would not be fully burned. To overcome this problem, I thought of a big combustion chamber that is divided into four quadrants by relatively thin separators. The pressure difference between the quadrants would be minimal and this allows thinner and lighter separators. Combining four combustion chambers into one would reduce the weight and cost of the engines. This design also allows the output of these combustion sections to be combined into a single nozzle. The pre-burners and the turbopumps can also be combined for these four engines. As a result, high efficiency, high thrust engines can be utilized on the rocket. Controlling one combo engine would be simpler compared to four independent engines.

In order to simplify the design, I also removed the regenerative cooling from the engine nozzle. Instead, pre-burners would heat up the propellant in a close loop system. The cooling of the nozzle would be achieved by directed bypass air. A duct surrounding the nozzle would guide the ambient air to cool the nozzle. The heated bypass air would than generate additional thrust by the ducted design.