DAMAGE MITIGATING CONTROL OF A REUSABLE ROCKET ENGINE: PART II - FORMULATION OF AN OPTIMAL POLICY

摘要

The goal of damage-mitigating control in reusable rocket engines is to achieve high performance without overstraining the mechanical structures; and the major benefit is an increase in structural durability with no significant loss of performance. This two-part paper investigates the feasibility of damage-mitigating control of the Space Shuttle Main Engine (SSME). A creep damage model of the main thrust chamber coolant channel has been formulated and verified in the first part. This paper, which is the second part, synthesizes an optimal policy for open loop control of up-thrust transients of the SSME. Optimization is based on the integrated model of plant, structural and damage dynamics under fatigue and creep damage constraints in the critical plant components. The results are presented to demonstrate the potential of life extension of reusable rocket engines via damage mitigating control. The concept of damage mitigation, as presented in this paper, is not restricted to control of rocket engines. It can be applied to any system where structural durability is an important issue.