Copenhagen, Denmark : Copenhagen Suborbitals succesfully tests a hybrid rocket booster, the XLR-2, which is part of a planned series of rocket tests exploring and validating safe and dependable rocket propulsion technologies to be ultimately used in a man-rated suborbital space vehicle.
This rocket engine design is highly dependable and permits throttle control. The XLR-2 was built and designed by Peter Madsen and Kristian von Bengtson.
The solid fuel is epoxy resin, a synthetic rubber compound which does not burn by itself, without an oxidizer. The engine is started when a pyrotechnic charge is electrically fired to set off the epoxy, which then only smoulders and is producing no thrust until the nitrous oxide is injected under pressure as a combustion catalyst. The peak chamber pressure here is about 36 atmospheres (~530 PSI).