A Novel Flare Maneuver Guidance for Approach and Landing Phase of a Reusable Launch Vehicle

Various algorithms have been used in the past to create a feasible reference trajectory to guide a Reusable Launch Vehicle from Approach and Landing interface to the desired touchdown point on the runway. Traditional Shuttle guidance scheme relies on a set of fixed trajectory segments during this phase. Further, this is followed by the development of several onboard and offline computational methods to design a reference profile. This paper proposes a nominal profile comprising of two segments; the steep glideslope followed by a novel flare maneuver scheme for safe touchdown on the runway satisfying all the constraints. Besides being an onboard generation method which generates a trajectory based on current vehicle states, the scheme consist of only two segments which is analytically simpler for mathematical computations. Simulation results validate that the proposed quadratic flare maneuver for touchdown allows for a lesser load factor. Moreover, the vehicle experiences lower peak dynamic pressures at higher altitudes compared to other schemes.