Experimental validation of hydrazine reaction model through hypervelocity impact tests

Abstract

The impact of debris on a satellite can result in a catastrophic event that not only destroys the spacecraft but it can also generate additional debris in space threatening the sustainability of space activities. Therefore, the design of spacecraft and its critical components require some understanding of the potential damage that can be inflicted by such event. For hydrazine fuel tank located outside the spacecraft, it is important to evaluate the conditions that may lead to its explosion in case of impact.This study aims at investigating through experimental tests, the temperature and pressure range for which hydrazine reacts under hypervelocity impact. The investigated tank conditions are representative of the temperature and pressure typically encountered for a satellite at the end of operational life i.e. with some residual remaining hydrazine in the tank. The main challenge of the project is related to the complexity and the hazard of the handling hydrazine. A specific test configuration and process have been developed for the safety of the operators and the surrounding environment. An ultra-fast valve was designed to isolate the target chamber right after the crossing of the projectile and before any hydrazine vapor comes back towards the gas-gun. The process prevents any direct contact of the laboratory personal with hydrazine. Four instrumented tests have been performed on small container impacted by stainless steel ball of 3 mm diameter at 6 km/s. A hydrazine reaction triggered by the impact has been detected on two tests with the highest temperature. In one case, the released energy has led to a catastrophic failure of the reservoir. These results are valuable for the calibration of a hydrazine thermochemical reaction model of satellite reservoir impact behavior even though the ignition process is not clearly established yet.