Challenges and development of avionics: flight termination system

Abstract

The aim of Flight Termination system (FTS) is to break launch vehicle (LV) flight down in case of rocket malfunction in the such way that rocket debris shall not fall down out of safety zone that is set beside rocket track on earth. There are two principal FTS architectures. First one came from rocket technology of soviet era and it was fully autonomous and automatic. Systems based on this architecture make decision using inertial system data only. On the contrary, second type systems use data from ground radar tracking systems and decision to interrupt flight is made by operator. All US LV are equipped with such kind FTS because US safety rules require this architecture as mandatorily. First one is automatic, fast and reliable  but can`t recognize fault due to error in LV flight program. Another one doesn`t have this problem but has human in control loop. No progress has not occurred in FTS system during long time until the first post-soviet LV “Zenith” came to US territory with Sea Launch project. Despite “Zenith” FTS wasn`t in compliance with US safety rules LV “Zenith” has took Federal Aviation Administration approval for launches due to special features of LV “Zenith” trajectory. That fact has opened understanding that another architecture could be acceptable. As a result, the searching a new approach to formulate safety requirements has started. Then safety requirements was changed on the base of risk management theory that permitted for Space X to develop revolutionary new FTS that is autonomous, automatic, reliable and use two independent channel to make flight termination decision. Thus, conclusion of the paper is that requirements formulated on the base of risk management are significantly more versatile than statements about mandatory performance and they open different ways for designers to find optimal decision. Exactly such safety rules are expected in Ukraine because until now any normative document that regulate flight safety is absent in Ukraine.