Expansion of landing areas on the Venus surface using resonant orbits in the Venera-D project

TL;DR

This paper proposes a gravitational resonance orbit method to significantly expand Venus landing site options for the Venera-D project, increasing accessible surface area at the cost of longer mission durations.

Contribution

It introduces a novel approach using Venus's gravitational field to create resonant orbits, greatly expanding potential landing sites beyond traditional constraints.

Findings

Over 70% of Venus surface can be reached with the method.

The approach allows access to nearly any point on Venus surface.

Flight duration increases by approximately one Venusian year.

Abstract

A problem of determining attainable landing sites on the surface of Venus is an essential part of the Venera-D project aimed to explore the planet using a lander. This problem appears due to the inability for the descent module to land at any point on the surface of Venus because of the short duration of the launch window (about 2 weeks from the optimal launch date), as well as restrictions on the maximum permissible overload. An additional factor affecting the reduction of attainable landing sites is the low angular velocity of Venus own rotation. This study proposes a new approach to expand the attainable landing areas. The approach is based on the use of the gravitational field of Venus to transfer the spacecraft to an orbit resonant to the Venusian one with a ratio of periods of 1:1. All the simulations were performed at the patched conic approximation. As an example, we considered a flight to Venus at launch in 2029 or 2031. For both cases maps of attainable landing areas on the surface were constructed. It has been demonstrated that there is always at least one launch date within the launch window, allowing the spacecraft to reach almost any point on the surface of Venus. It is shown that the application of the proposed approach makes it possible to achieve a significant expansion of the attainable landing areas (over 70\% of the surface) and, in some cases, provide access to any point on the surface of Venus. However, the price of this advantage is an increase in the flight duration by one Venusian year.