HyImpulse

HyImpulse builds rockets whose fuel is a block of paraffin. The fuel stays solid and the oxidiser, liquid oxygen, sits in a separate tank, so the two cannot mix by accident and the engine needs far less plumbing than a liquid one. The SR75 sounding rocket carries up to 250 kilograms to 200 kilometres, and the SL1 orbital launcher being designed around the same motors is meant to put about 600 kilograms into low orbit at first.

Christian Schmierer and Mario Kobald developed the motors at the German Aerospace Center's Institute of Space Propulsion, where the paraffin work began in 2006, and founded the company in Neuenstadt in 2018 with Konstantin Tomilin and Ulrich Fischer. The company's bet is that a simpler motor beats a more efficient one for a small launcher, because simpler is cheaper to build and safer to handle.

The SR75 has flown once, from the Koonibba test range in South Australia in May 2024, and a second flight is planned from SaxaVord in Shetland between 5 and 18 October 2026. The company extended its Series A by more than €50 million in September 2026, with JOIN Capital and Ace Capital Partners leading, taking total funding to about €125 million against an order book it puts above €350 million. The SL1 has not flown, and its first orbital attempt was last expected in 2027.