Polaris Spaceplanes

Polaris Spaceplanes is a Bremen, Germany-based launch startup founded in 2019 developing a concept for fully reusable horizontal take-off, horizontal landing (HTHL) spaceplanes that could launch from conventional airport runways without requiring dedicated vertical launch infrastructure. The company's Aurora spaceplane concept targets up to 1,000 kg payload to low Earth orbit and a reusability goal of up to 200 flights per vehicle — theoretical economics that would dramatically reduce per-kg launch costs if achievable.

HTHL spaceplanes use a combination of air-breathing jet engines for the lower atmosphere and rocket engines for the upper atmosphere and orbit insertion, landing back on a runway like an aircraft after reentry using thermal protection systems and aerodynamic glide capability. The runway-launch flexibility is a significant potential differentiator — any major commercial airport becomes a potential launch site, eliminating the geographic and infrastructure constraints of vertical launch pads.

These technical challenges are formidable: combined-cycle propulsion (efficiently transitioning between air-breathing and rocket modes), thermal protection for reentry at orbital velocities, and structural mass fractions competitive with expendable rockets have blocked similar programs for decades (including Sänger II, the British HOTOL, and ESA's various Hopper studies). Polaris Spaceplanes is competing in a conceptual space alongside Reaction Engines' Skylon (UK) and is at early development stage, working to demonstrate propulsion and aerodynamic concepts before committing to full-scale vehicle development.