Liquid Rocket Engine Concept for SMILE Launcher

The development of the liquid propellant engine within the frame of the SMILE Project is described in the current paper. The analysis of a generic liquid propelled rocket launcher was performed and resulted in a description of the engines of each stage. The focus of this work is on the performance analysis of the first stage engine. As the liquid engine concept for the first stage aims for a cost efficient solution, three separate concepts are discussed. Thus, a conventional bell nozzle main combustion chamber and two aerospike concepts with multiple combustor chamber configurations geometries are compared and evaluated with respect to each other. The basis for the analytical comparison is a weight driven performance calculation. It is shown that 30 unitary combustion chambers in linear aerospike configuration can compete, regardless of their higher weight, against the other two concepts. An analytical calculation for the maximum change of velocity for each configuration is performed over a variable initial acceleration of the first stage. The analysis indicated only a minor impact on the change of velocity, the difference between best and worst performing configurations is less than 30 m/s, assuming an initial acceleration of 1.4 for the first stage. It can be further stated that a structure, which is fully dependent on the initial acceleration, results in minor differences of the change of velocity for the first stage