X-RATOS II-ELVIS

The pyrotechnic nozzle plug of X-RATOS II was replaced by a pressure sensitive valve assembly. The valve serves to fill the high pressure tank under standard conditions and can be opened remote controlled at 270°C (520°F) and 60 atm in good distance from the vehicle. Due to the rather short thrust phase which depends on the nozzle throat diameter and which amounts to only a few seconds, the valve has to fulfil the requirement to be opened in a very short time that should be well below one second. The valve still has to be leak tight when the heated water is under high pressure. It has been decided to use the valve assembly instead of a pyrotechnic closure since it implies a clear qualitative improvement in terms of safety, wear resistance, ease of operation and reproducibility.

Fig. 5:  AQUARIUS X-RATOS II-ELVIS with electro-pneumatic valve control: CAD design (left) and ready for test operation (right)

ELVIS stands for "ELektro-pneumatisches VentIlSystem" which means electro-pneumatic valve assembly. It has been designed in a way that necessary modifications of existing X-RATOS II components remain as marginal as possible. Those parts of the valve assembly that are attached to the vehicle were designed as a demountable docking module being fully compatible with the aft section of the demonstrator. This way X-RATOS II can be easily rebuilt for classical operation by detachment of the whole valve assembly module. The high success rate of the first tests allowed to expect further technological development of the whole system, e.g. by integration of a sensor and telemetry system for real-time monitoring of crucial operation parameters.