Optimal Skip Entry Trajectory for Lunar Return Vehicle with Trim-Flaps

Yin Wang,Keming Yao

doi:10.1155/2017/3498350

Abstract

A medium lift-to-drag ratio lunar return vehicle with trim-flaps is presented in this paper. The trajectory optimization design under heat-rate constrain for skip entry lunar return vehicle is analyzed. The optimization problem with a first-order state constraint is introduced. The trajectory applying the Pontryagin maximum principle under the performance of minimum heat is optimized, and the optimal expression of lift coefficient is derived. The simulation studies show that this research method can decrease the heat-rate effectively.

Highlights

When the lunar return vehicle reenters the atmosphere, its speed is up to 11 km/s, and its kinetic energy is about twice that of the near-earth orbiter
The vehicle with trim-flaps is a kind of medium lift-drag ratio vehicle, which has a simpler structure than that of lift type vehicle
Since the 1990s, scholars like Shui et al [4,5,6,7] have done some studies in conceptual design and return optimal trajectory for vehicles with trim-flaps

Summary

Introduction

When the lunar return vehicle reenters the atmosphere, its speed is up to 11 km/s, and its kinetic energy is about twice that of the near-earth orbiter. Increasing the return capsule lift-drag ratio and using the way of skip reentry can improve the safety performance of the return vehicle. It can significantly improve the maneuvering ability of the lunar return vehicle and offer more choices for spacecraft landing site [1,2,3]. Istratie et al have done a series of studies in the initial reentry optimal trajectory design of the near-earth orbit skip reentry [8,9,10,11]. A return vehicle with trim-flap is used as the lunar return vehicle model; the optimization problem with a first-order state constraint is introduced; the trajectory applying the Pontryagin maximum principle under the performance of minimum heat is optimized and the optimal expression of lift coefficient is derived in this paper

Reentry Model of Sample Return Vehicle

The Description of Optimal Reentry Problem

Optimal Trajectory Design

Simulation and Analysis

Conclusion