T GE Aerospike: making the unmakeable
Making the unmakeable: How metal AM is bringing the aerospike rocket engine to life The history book of engineering is filled with concepts that failed to achieve success because they were ahead of their time. This was almost the case for the aerospike rocket engine, recognised in the 1950s as a strong concept and tested by NASA in the 1980s and 1990s, but found to demand too much of the manufacturing and materials technology available at the time. Metal AM magazine spoke with Pangea Aerospace and Aenium Engineering about reinventing the aerospike for the 21st century, and how Additive Manufacturing allowed them to 'make the unmakeable' – pushing their expertise in AM, materials science and Design for AM to its limits in the process.
Aerospike rocket engines were first conceived in the 1950s as a highperformance alternative to more traditional bell nozzle configurations. However, the shutdown of major space programmes, together with the manufacturing effort associated with their complexity, led to a period of relatively low research and industrialisation effort. Recently, aerospike engines have experienced a resurgence of interest because of their altitude adaptation properties and advantageous performance characteristics compared to bell nozzles. Furthermore, the ongoing maturity level of Additive Manufacturing processes and materials for propulsion applications makes it possible to build an economically viable aerospike engine with reduced lead time. Two European companies based in Spain, Pangea Aerospace, and Aenium Engineering, are working together to advance the aerospike concept for the 21st century through a focus on nozzle design, advanced AM processing and post-processing, as well as exploring material science and metallurgical approaches on new high-performance copper alloys to resist the harsh heat flux/mechanical
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strength requirements of this application. The alliance between both these companies has resulted in a breakthrough in aerospike rocket engines and the firing of the first liquid oxygen/liquid methane (LOX/ LNG) dual regeneratively cooled aerospike to be additively manufactured in history. DemoP1 packs 20 kN (~2 tons) of thrust in just above the
dimensions of a football. It does that thanks to a combustion chamber pressure in excess of 50 bar and a near-stoichiometric mixture ratio, yielding a hot and energetic flame causing heat fluxes in the walls up to 50 MW/m2. These numbers make DemoP1 an ambitious demonstrator to design and operate, especially at this small scale where cooling
Fig. 1 A close up view of Pangea Aerospace’s aerospike engine (DemoP1) (Courtesy Pangea Aerospace)
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