Application of Re-entry survivability analysis tool to mars planetary protection

Abstract

JAXA develops the Object Re-entry Survival Analysis Tool - Japan (ORSAT-J), which is a tool to assess the survivability and risk to the ground of objects re-entering from low Earth orbit. This tool is derived from NASA's ORSAT ver. 4.

ORSAT-J can calculate the temperature of an entering object during its entry into a celestial body with respect to the elapsed time. Therefore, in terms of planetary protection, it could be used to evaluate whether aerodynamic heating during celestial entry is sufficient for sterilization in the event of an Earth-derived spacecraft entering into a celestial body due to an accidental event. JAXA plans some Martian biosphere exploration missions such as the MMX mission, and is aiming to build a tool that can easily analyse the aerodynamic heating during Mars entry.

In this paper, we collected and evaluated the information such as celestial geometry, gravity model, atmospheric model, radiative heating, etc. necessary to perform a Mars entry heating analysis with ORSAT-J. These were applied to the code and compared with the measured data of Schiaparelli of the ExoMars Program. The novelty of this paper is that it introduces a comprehensive analysis method for Mars entry, including trajectory and heating simulations, into a simplified survivability analysis tool for the on-ground risk of re-entry into Earth.