German start-up POLARIS Spaceplanes has made a breakthrough, successfully completing roll and flight tests of its MIRA II demonstrator. Powered by the company’s 3D-printed AS-1 linear aerospike engine, the five-meter-long prototype represents, if not a giant leap for humanity, a critical step toward the development of the full-scale AURORA spaceplane, scheduled to debut in 2028.
The unmanned MIRA II took off from Peenemünde Airport with the help of jet turbines and achieved a three-second in-flight burn of its 1 kN LOX/kerosene aerospike engine over the Baltic Sea. Generating 900 newtons of thrust, the test is the first-ever airborne trial of a linear aerospike engine – despite a minor LOX tank leak that resulted in the loss of an access hatch.
Aerospike engines use a wedge-shaped design to optimize thrust across altitudes, enhance efficiency, and reduce weight, in contrast to traditional bell-nozzle engines. The bad news is that their intricate cooling systems and extremely high operational temperatures require advanced manufacturing techniques. With POLARIS embracing additive manufacturing, 3D-printed components are made by AM Global, enabling rapid iteration and reduced stress testing betweenMIRA II’s flights.
In the future, POLARIS plans to fine-tune its engine technology through its twin demonstrator, MIRA III, while preparing for NOVA, a larger prototype, before AURORA’s 2028 launch. These tests definitely signal a step forward in aerospace propulsion innovation.
Source: https://europeanspaceflight.com/
