On 12. June 2013 the third test fire of the DHX-200 “Aurora” hybrid rocket motor took place at the facilities of TNO. The Aurora motor will power the Stratos II rocket and utilizes nitrous oxide as oxidizer and a fuel combination of sorbitol, paraffin wax, and aluminium particles as fuel.
The motor was intended to be fired for 15 seconds after the successful 10 second test earlier this day but was shutdown prematurely at around 6 seconds after the combustion chamber showed local structural failure.
The sequence involves the following steps:

T — 4s : Nitrous Oxide bypass flow initiated
T — 3s : Ignition pulse for pyrotechnic igniter
T 0s : Main valve open
T + 6s : Main valve closed (safety precaution)
T + 15s : Scheduled motor cut-off

Read the full story on: http://projectstratos.nl/2013/06/2011/