Precautionary Planetary Defence

TL;DR

This paper explores complex decision-making scenarios in planetary defence, focusing on risks of human missions and active asteroid management, using Apophis as a case study to inform strategies for asteroid deflection and safety.

Contribution

It introduces a framework for managing asteroid threats considering mission risks and active asteroid repositioning, expanding on existing planetary defence decision models.

Findings

Active management can reduce impact risk effectively.

Mission risks influence deflection decision thresholds.

Case study of Apophis demonstrates practical application.

Abstract

The question of whether to attempt deflections during planetary defence emergencies has been subject to considerable decision-making analysis (Schmidt 2018; SMPAG Ad-Hoc Working Group on Legal Issues 2020). Hypothetical situations usually involve a newly discovered asteroid with a high impact probability on a set timescale. This paper addresses two further complexities: (1) limiting missions to an asteroid due to the risk of a human-caused Earth impact; and (2) active management of asteroids to place them in "safe harbours", even when impact risks are otherwise below "decision to act" thresholds. We use Apophis as a case study, and address the two complexities in turn.