In May 2008, two men climbed into a 40-ton submarine docked at an abandoned Copenhagen shipyard. One of the men had built the 58-foot-long sub in his spare time, and inside they chatted about the future. It involved rockets — big rockets.

Although it was the first meeting between Kristian von Bengtson and Peter Madsen, the submarine‘s creator, the duo emerged with a daring plan: to launch themselves into suborbital space using custom-built contraptions. And with that, Copenhagen Suborbitals was born.

Co-founders von Bengtson, an aerospace scientist and former NASA contractor, and Madsen, an entrepreneur and aerospace engineer, have a lot to be proud of since they founded their non-profit space program four years ago. In June 2011, for example, Copenhagen Suborbital’s army of volunteers successfully built, launched and recovered a 31-foot-tall rocket — the largest “amateur” launcher ever built — with a crash-test dummy tucked inside.