Polaris will build a two-stage, horizontal take-off and fully reusable hypersonic research vehicle, featuring a linear aerospike rocket engine.
German company Polaris Spaceplanes announced on Jan. 27, 2026, that it has received a contract from the Federal Office of Bundeswehr Equipment, Information Technology, and In-Service Support (BAAINBw) to build and flight-test a reusable hypersonic vehicle. The company says the vehicle has to be flight ready by the end of 2027.
The vehicle has been further described as a two-stage, horizontal take-off and fully reusable hypersonic research vehicle, with the size and maximum takeoff weight of a fighter jet. The firm’s statement on its LinkedIn page said that the project has both civilian and defense applications, serving as an experimental testbed and a small satellite launch platform.
Called the Hypersonic Test and Experimentation Vehicle (HYTEV), the project follows nearly two years of preparatory work, says the company, following BAAINBw contracts in April 2023 and February 2025 to develop a linear aerospike rocket engine and design the HYTEV, respectively. The company has designated the aerospike engine as AS-1, and has been testing small-scale demonstrators MIRA II and MIRA III for more than a year now, recording a few milestones so far.
The MIRA II experienced a major success on Oct. 29, 2024, when it fired the AS-1 mid-air, making it the first ever in-flight ignition of a linear aerospike rocket engine, the company said. Polaris revealed in November 2025, along with extensive footage, that the program had completed 250 flights in seven demonstrators.
The final fighter-sized aircraft will be powered by two turbofans and the AS-1 aerospike engine, with a rocket-powered upper stage.
Aircraft and milestones so far
Polaris said in its LinkedIn post: “We are extremely pleased to announce that POLARIS has received a BAAINBw contract for manufacturing and operating a two-stage, horizontal take-off and fully reusable hypersonic research vehicle.”
The November 2025 footage included a small clip of the airframe of a larger aircraft being under construction, which will have naturally incorporated lessons from the small-scale demonstrators. This could probably be the supersonic NOVA demonstrator, based on the development roadmap POLARIS has previously revealed.
Hartpunkt, quoting unidentified company officials, put the expected space payload weight at 1,000 kg, a targeted hypersonic speed exceeding Mach 5, and said a possible role could be “reconnaissance missions outside the atmosphere.” Another clip in the November 2025 video showed one of the sub-scale MIRA aircraft being refueled by the other, but it is not known if they were controlled manually or were operating autonomously.
Germany is making one of its biggest pushes into advanced aerospace in recently. Government officials have confirmed a significant investment in spaceplane research, signaling that the country plans to take a much more serious role in the future of reusable flight.
The… pic.twitter.com/oRdfKHinf4
— Dylan Small (@_DylanSmall_) November 25, 2025
The MIRA aircraft are largely a flying-wing type, with two large winglets, and four large protruding air inlets above the wing’s leading edge. The aerospike engine sits in the centerline, running across the aircraft’s spine, between the four exhausts of the two turbofan engines.
Polaris’s LinkedIn post further said: “The main purpose of the two-stage system is to serve as hypersonic testbed and experimental platform for defense-related as well as scientific/institutional research. In a secondary function, the vehicle can be used as a spaceplane for launching small-satellites when using an expendable upper-stage […] We are incredibly proud about the continuous trust of the Bundeswehr in our competences. As far as we know, a contract for a comparable system was never awarded before to an entity in Europe, maybe even worldwide.”
First in-flight Aerospike rocket engine ignition
European Spaceflight, in a Nov. 12, 2024, report about the AS-1’s first in-flight ignition test with its in-house 1 kN LOX (Liquid Oxygen)/kerosene fuel on the MIRA II, said that its “twin,” the MIRA III, has been developed for greater redundancy and testing flexibility, and will lay the foundation for the supersonic NOVA demonstrator. This will inform the final AURORA reusable hypersonic spaceplane, which the latest BAAINBw contract covers, to deliver payloads into Low Earth Orbit (LEO).
In its LinkedIn post, POLARIS Spaceplanes also said that the MIRA II became on Oct. 29, 2024, the first vehicle to fire an aerospike engine mid-flight. It took off from the Peenemünde Airport, igniting the aerospike over the Baltic Sea, “approximately 3 km away from the ground station.”
For safety reasons given this was the aerospike engine’s first flight, POLARIS engineers reduced the propellant loading equivalent to only 229 kg, limited the burn time to 3 seconds and operated under reduced chamber pressure.
The AS-1 accelerated the MIRA II to 4 meters/second squared, generating 900 N of thrust, while simultaneously giving it altitude. After the fully successful first aerospike flight, MIRA II returned to the airport and landed safely.
The flight took three-and-a-half minutes in total, covering a distance of more than 10 km. Future flight tests will “extend engine operation range and vehicle performance envelope,” POLARIS added.
“While gearing up for the next aerospike flights with MIRA II and its twin sister MIRA III, we are already preparing the development of the supersonic prototype NOVA, which will have a length of 7-8 meters,” said the company.
Aerospike rocket engine
Compared to a conventional rocket engine with a bell-shaped exhaust, an aerospike inverts into an inward-facing curve, with the exhaust flowing over the exterior side exposed to the surrounding atmosphere.
Bell-shaped nozzles are optimized for a specific expansion ratio which corresponds to a particular altitude, and become progressively less efficient away from that point. This is one of the reasons multi-stage rockets are used, as they allow to employ upper stages with larger expansion-ratio nozzles optimized for the progressively higher altitudes, up to the near-vacuum operation.
In an aerospike design, the exhaust being directly exposed to the outside atmospheric pressure, offers better efficiency. However, technical hurdles like more complex designs, heavier engines, and increased cooling requirements, compared to bell-shaped nozzles, have marred previous efforts.
Decades ago, at the time of the first aerospike efforts, available materials and cooling techniques made it difficult to manage the thermal loads and structural complexity of aerospike engines, limiting the results that could be achieved. Among the first to work on aerospike was Rocketdyne, which invented the design in the 1950s.
In the 1990s, NASA and Lockheed Martin pursued the X-33/VentureStar program as a single-stage-to-orbit (SSTO) vehicle with a linear aerospike rocket. While the program led to the creation of a partially built prototype, it was cancelled in 2001 after major technical failures and escalating cost and schedule overruns.
