Method for the Situational Terminal Control of a Descent Vehicle on a Skip-up Return Trajectory from the Moon

A method of situational adaptation is proposed to control the movement of the descent vehicle (DV), which, upon returning from the Moon, enters the Earth’s atmosphere at a near-parabolic velocity from the southern hemisphere, uses a skip-up trajectory with two re-entries into the atmosphere, separated by an extra-atmospheric (ballistic) section, and lands in a limited area in the south of the Russian Federation. Here, situational is understood as the adaptation of the onboard motion model to the actual perturbances acting in each specific implementation of the descent trajectory. The two-parameter terminal control method uses separate adaptation for aerodynamic performance errors, perturbed atmospheric density, and a navigation altitude error. This allows accurately guidance to the landing site, as well as limiting lift-to-drag ratio and fuel consumption.