Quasar is a homemade hybrid rocket motor designed by Cambridge University Spaceflight. The oxidiser is nitrous oxide and the fuel grain is made from sugar.

Thrust and plumbing pressure during successful ignition test.

It has had two test firings so far with the first successful ignition, albeit without choked flow, occurring on the 15th March 2014.

There are two pressure taps in the motor and plumbing assembly: one to measure pressure upstream of the injector and the other to measure chamber pressure. During operation the motor is fixed to our static test rig for axial thrust measurement and three thermocouples are fixed to various locations along the outside of the combustion chamber.

Plumbing assembly

After difficulties in achieving ignition during the first test firing the plumbing was modified to allow a small ‘bypass’ flow to gently waft nitrous down the combustion chamber for easier ignition before the main valve is opened.