Method for calculation of takeoff parameters of lunar ascent module based on orbital coplanar rendezvous
Abstract
<p indent="0mm">To solve the lunar orbit rendezvous problem, in which the ascent and orbital modules are coplanar to achieve fuel consumption optimization, a method that accurately determines the ascender’s takeoff parameters is proposed. Based on the lunar takeoff position of the ascent module and flight orbit of the orbital module, an analytical model for calculating the initial values of the takeoff azimuth and the takeoff time is presented using the spherical triangle relationship of the orbit plane passing through the takeoff site. The injection orbit of the ascent module is calculated based on its lunar ascending characteristic parameters. The four-pulse long-range guidance orbit maneuver strategy is adopted to realize the rendezvous orbit maneuvers of the ascent module. The mapping relationship between the orbital plane deviations of the long-range guidance terminal of the two-spacecraft rendezvous and the orbital parameter deviations of the injection orbit is established. The analytical algorithm for correcting takeoff azimuth and takeoff time based on orbit inclination deviation and the ascending node right ascension deviation is derived. Further, an iterative calculation process for precise lunar takeoff parameters is designed. Simulation results verify the correctness and rapid convergence of the initial value and correction methods for the lunar ascent module’s takeoff parameters. The long-range guidance terminal normal deviations are effectively eliminated by the precise lunar takeoff parameters obtained based on the orbital coplanar rendezvous. The optimized rendezvous orbit maneuver without orbital plane correction saves the ascent module’s propellant consumption. The method for calculating takeoff parameters can be used to optimize and determine the takeoff parameters for rendezvous and docking from the moon and other extraterrestrial bodies.</p>
