INNOVATIVE NAVIGATION TECHNIQUES FOR AUTONOMOUS NEO PROXIMITY AND LANDING OPERATIONS

Autonomous GNC systems are one of the enabling technologies for many of the future ESA exploration missions. One of those innovative missions is an asteroid sample return mission aiming at small (<1 km) near- Earth asteroids. During the proximity, landing and sampling (PLS) operations, the GNC system will be challenged by some critical factors, namely (1)the extremely tight requirement on the landing accuracy of few metres (3-sigma), (2)the large uncertainties in the asteroid characteristics that define the dynamics during the PLS operation, (3) the weak gravity field creates a small sphere of influence where the orbits around the asteroid are strongly perturbed by the solar radiation pressure, the Sun third body effect and the irregularities of the asteroid gravity field, (4) cost and technological limitations also constrain the selection of the navigation sensor suite and the GNC strategy. The design of possible autonomous GNC solutions will be presented for different proximity operations phases. The proximity operations shall considering the realistic a priori knowledge, the ground involvement and the on-board autonomy periods. High-fidelity simulations will provide the performances of the GNC systems in the different phases of the NEO proximity and landing operations.