Today we attempted to launch the Stratos II+ rocket to 50 km altitude and did not succeed. While there were no major technical hiccups during the countdown, the rocket stayed in the tower after the countdown went to zero. We are currently still in investigation further root causes, but this is what we know.

The main observation was that the rocket engine did not ignite properly. There were no leaks at all in the rocket, so it was definitely not a frozen valve. The ignition valve was found not able to open under the 60 bar tank pressure, while is does open at 55 bar. The exact issue why the valve did not open is still unknown, but we are currently working on it. The ignition valve is a small valve that makes sure the motor is preheated before the main valve opens that makes 3.5 kg of nitrous oxide flow into the motor every second. Without an ignition valve, opening the main valve will just blow out the motor like you blow out a candle.

This is what dumping 85kg of Nitrous Oxide looks like

So why didn’t we catch this problem before hand? The reason is that it is difficult and expensive to perform a cold flow test with the complete rocket. Extensive tests have been performed with the ignition valve but never in an completely integrated system at these pressures. While we now have a good clue we’ll have to keep looking if this is the root cause. In addition the team still needs to find a solution for this problem. We are however confident that we can finish this process before tomorrow afternoons launch window.

We had a meeting at 19:00 with the INTA launch base to decide further action. We are confident we can fix the ignition valve before tomorrow, and have therefore decided to do another launch attempt in the afternoon launch window from 16:00 CEST onwards. Follow us live on Ubideo!