We just received the final go from the INTA personnel at the El Arenosillo launch base to launch the Stratos II+ again this afternoon. Our launch window opens at 16:00 CEST and we will start our preparations around 11:00 to make the launch happen at 16:00 or slightly later. You can again watch the launch live.
Upping the voltage
As we told yesterday already the igniter valve failed to work properly yesterday, which caused the engine to fail to ignite properly. When the main valve opened the engine was blown out like you blow out a candle.
While the ignition valve worked fine in all but one of our static propulsion tests, it still failed during the launch attempt. Yesterday we verified that the valve works at 55 bar pressure, but it won’t open at 60 bar pressure. Based on this we suspected that the solenoid in the valve was not able to draw enough power. Our static tests however worked at pressures around 55 to 60 bar as well, so we were surprised to found out this way that the valve power is to low. The reason why it worked in the tests and not in the rocket is probably due to the fact that rocket powers the valve using different cables.
To ensure that this problem is fixed we tested the valve as it is powered by the rocket to pressures up to 80 bar. By increasing the voltage the solenoid is able to draw more current, allowing it to work up to 80 bar.