Reentry Requirements on The Return of a Rapid Crewed Mission to Mars

Tiago Filipe Vieira da Silva

Key information

Authors:

Tiago Filipe Vieira da Silva (Tiago Filipe Vieira da Silva)

Supervisors:

Paulo Jorge Soares Gil (Paulo Jorge Soares Gil)

Published in

December 2, 2024

Abstract

In the future, it is reasonable to expect a crewed mission to Mars. However, the trajectories that minimize the propellant require a total mission duration of almost three years, with half of this time spent in the surface of Mars. This long duration can be a challenge due to prolonged exposure to radiation and reduced gravity. For this reason, it is desirable to reduce the overall mission time, considering rapid missions to Mars. Rapid missions are characterized by high speeds and, therefore, the velocity at arrival can be correspondingly high. Thus, it may exist the need to brake before reentry in order to safely return to Earth. The objective of this work is to analyze the feasibility and potential benefits, if existing, of a high-velocity reentry to Earth. The constraints of deceleration and heating during reentry are defined, alongside the characteristics of the spacecraft and the interplanetary trajectory. The Pareto fronts for the Initial Mass in Low Earth Orbit (IMLEO) were obtained for different mission durations shorter than one year considering two reentry strategies: maximum propulsive braking and high-velocity reentry. For the current available propulsion systems, the high-velocity reentry scenario allowed gains of approximately 70% but, for the advanced propulsion systems, the mass penalty from the heavy heat shield outweighs any propellant savings. Therefore, mass benefits associated with the IMLEO reduction were found to be very contingent on propulsion system efficiency. As it increases, the mass benefit transitions to lower values and eventually becomes disadvantageous for more advanced propulsion systems.