Launcher E-2 thrust chamber assembly on its test stand at NASA Stennis Space Center. Photo: Launcher/John Kraus Photography

US-based Launcher’s 3-D printed E-2 liquid rocket engine successfully demonstrated nominal thrust, pressure and oxidiser/fuel mixture ratio for the first time in a test fire at the NASA Stennis Space Center, which took place last week.

E-2 is a closed cycle 3-D printed, high-performance liquid rocket engine in development for the Launcher Light launch vehicle which is scheduled to launch in 2024. A single E-2 engine will boost Launcher Light to low Earth orbit with 150kg of payload.

Data from the successful test fire of the E-2 engine showed that the engine had 10 metric tons of thrust, 100 bar of combustion pressure and the highest performance 2.62 propellant mixture ratio for LOX/Kerosene at 100 bar of pressure.

E-2’s chamber is uniquely liquid-oxygen cooled and 3-D printed in copper alloy in a single piece. It also uses industrial supply chain copper chromium zirconium alloy (CuCrZr), reducing costs and supply chain constraints compared to aerospace-grade copper alloy typically used in 3-D printed combustion chambers.

Launcher is the first small-launch company to use 3-D printed copper alloy, and leads in small launch 3-D printed technology with its development of the first large format (100 x 45 x 45cm) custom 3-D printer in partnership with additive manufacturing specialist AMCM. Launcher’s single-part copper alloy combustion chamber is produced on an AMCM M4K 3-D printer.

In addition, E-2’s ‘state of the art’ co-axial injector is 3-D printed on a Velo3D Sapphire. These technologies enable higher performance which translates into more payload per rocket and lower prices for Launcher customers.

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Demonstrating its reusability, the chamber was in perfect condition after 40sec of total test fire time. As a next step, Launcher tests again in early May with the same chamber and injector, lightly reworked to remove all film cooling — which increases performance.

In March 2022, Launcher successfully tested E-2’s turbine and liquid-oxygen pump in boost mode at 130% nominal flow. Launcher expects to demonstrate a full duration, 3min test with the E-2 integrated turbopump in closed cycle configuration by the end of 2022.