Aerospike Ramjet Rocket

Famous Falcon 9 rocket’s nozzle is made of Niobium, propellent tanks are made of aluminum-lithium alloy, turbopump turbines are made of Nickel Chrome Superalloy. This list continues. In addition to the cost and manufacturing difficulty of these expensive materials, the geometry and the complexity of the engine is also beyond the reach of many. I had previously proposed much simpler rocket designs and now comes a new one.

The idea is to turn the engine of the rocket into a staged ram and scramjet. The air inlet cone attached to the bottom of the rocket and the air inlet cone of the upper stage will collect and compress the incoming air to be burned by the fuel droplets at the bottom of the rocket. This cone will serve as an aerospike nozzle and will direct the exhaust gas for an efficient thrust. The fuel will drip from the tiny nozzle holes drilled on the bottom of the rocket. Initially they will be covered by the solid booster propellent. Just before takeoff, this solid propellent will be ignited to clear up the nozzle holes. Additionally, the heat generated by the ignition will heat up the fuel and the air to initiate the combustion. This combustion would not be enough to lift off the rocket. Therefore, small solid boosters strapped around the first stage of the rocket will also be started. As the rocket gains speed and looses weight it will keep accelerating. The objective of this stage is to raise the rocket above the clouds and give it a sufficient speed for the next stage to generate thrust without solid booster assistance.

There will be three stages with air inlet. Each one will be optimized for the speed it will be operating. This simplifies the design and reduces weight as the depleted stages are discarded. The fourth stage of the rocket will mostly travel through the vacuum to give the payload its orbital speed. I will explain it on my next article.

The rockets will be made of stainless steel for easy manufacturability and higher heat resistance compared to aluminum alloys. They would be cast into shape and then surface finished to allow mass manufacturability. The consumed rockets will fall to the earth slowed down by the parachutes. They will be collected from the sea to be recycled again.