Reliability and Quality Assurance Experience in Launcher Hold and Release System used in GSLV

Abstract

The launcher hold and release system (LHRS) was successfully used, for the first time, for GSLV-DI mission after thorough test and evaluation, in line with reliability and quality assurance (R&QA) requirements. Various R&QA techniques are applied to make LHRS failure-free. Failure mode effect and criticality analysis (FMECA) was used as a tool for identifying critical failure modes. Single-point failure modes (SPFMs) identified from FMECA are strengthened by design modifications and the same are verified by testing. Testing philosophy is tailored to have more number of tests at the system level. Capability demonstration tests and failure mode simulation tests were carried out during system qualification phase. Acceptance tests are done on the flight hardware at launch pad to demonstrate better confidence on the system. This paper illustrates how R&QA techniques complimented and added value at different stages in the development cycle of LHRS, by means of few case studies. Testing methodologies adopted and problems encountered during the development and qualification phases are described in brief. Various problems surfaced during preparation for flight are also discussed.