Improved Analytic Guidance Algorithm for Mars Entry

Abstract

With the development of Mars exploration, NASA has been preparing plans for a crewed mission to Mars in the next few decades. One challenge associated with crewed missions to the Mars is the high ballistic-coefficient and human-class payloads. Because of the high ballistic-coefficient, the maximum limit value of the reference flight path angle is always the reference flight path angle meeting the downrange and altitude for the constant flight path angle algorithm. So this paper presents an improved algorithm which the terminal velocity is controlled by dynamic pressure controller, and the controller is used to modulate the velocity and altitude to meet final constraints. Simulations results of a Mars entry scenario illustrate that the improved algorithm achieves the final constraints within allowable tolerances.