HyImpulse revolutionises access to space

Europe’s independent access to space is still developing, and it continues to rely on non-European providers for a significant portion of launches. In 2024, European providers conducted less than one per cent of all global launches (source: Space Economy Report 2024). HyImpulse is doing pioneering work in this area: the company's hybrid technology reduces the number of components by around 50 per cent, lowers costs and increases reliability – a decisive factor in establishing cost-efficient and flexible launch services in the sub-ton payload range.

Ahead of other space tech start-ups, HyImpulse reached a historic milestone in 2024: the successful test flight of the SR75 suborbital rocket demonstrated the functionality of a commercial paraffin-based hybrid rocket engine for the first time. This flight is considered a technological breakthrough and proof of concept and forms the basis for further stages of development. Building on the tests with the SR75, HyImpulse is working on the three-stage SL1 orbital rocket, which is expected to transport up to 600 kilograms of payload into low Earth orbit from 2027 onwards.

The launch vehicles are made of lightweight fibre-reinforced plastics. Stainless steel components are also used in the rockets and some of them need to be milled. Pokolm has supplied HyImpulse with a complete initial set of equipment consisting of holders, carrier tools and indexable inserts for machining these materials.

The fibre-reinforced plastic developed by HyImpulse is very demanding to process. The abrasive fibres cause significant tool wear. 

Fibre layers can become detached from each other, particularly at component edges, due to unfavourable cutting forces or incorrect cutting parameters. Insufficient cutting edge sharpness also leads to poor edge quality. 

The anisotropic material behaviour of fibre-reinforced plastics with different fibre orientations also causes widely varying cutting forces and makes it difficult to design a stable process.

Pokolm premium tools with PCD indexable inserts or diamond-coated indexable inserts are used for machining fibre-reinforced plastics. Diamond materials are significantly more resistant to fibre abrasion than conventional cutting materials. PCD (polycrystalline diamond) has extremely high wear resistance to abrasive fibres and produces very sharp cutting edges. As a result, PCD indexable inserts usually have a long service life.