Autonomous GNC Algorithms for Rendezvous Missions to Near-Earth-Objects

Abstract

This paper presents the design of an autonomous GNC system for the rendezvous phase of low-cost missions to very small, faint Near Earth Object (NEO). The optical navigation problem presents a strong relation between the approach strategy and the best combination of sensors, algorithms and actuators. First of all the problem is globally analyzed and the rendezvous strategy defined, from detection of the asteroid to insertion into a desired bounded orbit, considering the observability of the full spacecraft state relative to the asteroid. Then, for each sub-phase the GNC algorithms, including the Image Processing, are described for different propulsion systems (impulsive and low-thrust), and including or not an altimeter. Monte Carlo simulations for different NEO (Apophis and 2003 SM84) are run to tune the algorithms and to asses the system performances. The simulation tool includes high-fidelity models of the optical sensors (navigation camera and star-tracker). The conclusions show the driving parameters and the feasibility of the proposed GNC system.

New near-optimal feedback guidance algorithms for space missions

“…Gil-Fernández et al [7,8] describe various terminal-phase guidance laws of a kinetic impactor as applied to the European Space Agencys Don Quijote mission (now canceled). This work was continued in more detail by Hawkins et al [9].…”

Terminal-Phase Guidance and Control Analysis of Asteroid Interceptors

“…Navigation during the terminal phase of the mission will have to be autonomous, as computing and commanding accelerations via a communications link with Earth will be too time-consuming. 2,3 The interceptor must be able to issue guidance commands based solely upon on-board measurements. The quality of on-board measurements possible has been investigated in Refs.…”

Spacecraft Guidance Algorithms for Asteroid Intercept and Rendezvous Missions

“…Gil-Fernández et al [4,5] describe various terminal-phase guidance laws of a kinetic impactor as applied to the European Space Agency's Don Quijote mission (now cancelled). This work was continued in more detail by Hawkins et al [6].…”