Partial reconstruction of the rotational motion of Philae spacecraft during its landing on comet 67P/Churyumov-Gerasimenko

TL;DR

This study reconstructs Philae's rotational motion during landing on comet 67P, analyzing the effects of collision, gyroscope shutdown, and providing bounds on post-touchdown angular velocity to inform spacecraft design.

Contribution

It introduces a partial reconstruction method of Philae's rotation during landing, combining numerical simulation with in-situ measurements to analyze dynamic behavior.

Findings

Estimated lower bound of Philae's angular velocity after touchdown

Insights into the impact of gyroscope shutdown on stability

Assessment of collision effects on spacecraft dynamics

Abstract

This paper presents a partial reconstruction of the rotational dynamics of the Philae spacecraft upon landing on comet 67P/Churyumov-Gerasimenko as part of ESA's Rosetta mission. We analyze the motion and the events triggered by the failure to fix the spacecraft to the comet surface at the time of the first touchdown. Dynamic trajectories obtained by numerical simulation of a 7 degree-of-freedom mechanical model of the spacecraft are fitted to directions of incoming solar radiation inferred from in-situ measurements of the electric power provided by the solar panels. The results include a lower bound of the angular velocity of the lander immediately after its first touchdown. Our study also gives insight into the effect of the programmed turn-off of the stabilizing gyroscope after touchdown; the important dynamical consequences of a small collision during Philae's journey; and the probability that a similar landing scenario harms the operability of this type of spacecraft.