A proof-of-concept additively manufactured 4 kN sea-level thrust aerospike rocket engine driven by a pressure-fed combustion cycle running on compressed natural gas and gaseous oxygen. Featuring a two-piece construction consisting of the rocket engine body and compact altitude-compensating aerospike nozzle design, both part count and high-temperature metal-to-metal seals are minimised. By incorporating the aerospike nozzle design, significant improvements in overall engine efficiency are achieved.

The ProjectX engine was developed as a technology demonstrator to showcase the aerospike nozzle design and the advanced manufacturing techniques used to build it. Built with sub-surface water channels to actively cool the engine, the ProjectX aerospike rocket engine is capable of withstanding the extremely hot combustion temperatures generated during operation.