B2Space is a UK based smallsat launch venture that intends to use a high-altitude balloon as a platform to launch its rocket (i.e. the “rockoon” approach). This week the company announced a collaboration with the Swiss company RUAG, which is know for building composite fairings that protect satellites in the nosecones of rockets.
About us: www.b2-space.com “
The company also release a video showing a balloon flight test:
Here is a video from 2017 showing the B2Space launch system design: