ESA’S ASTEROID IMPACT MISSION: MISSION ANALYSIS AND PAYLOAD OPERATIONS STATE OF THE ART F. Ferrari, M. Lavagna Politecnico di Milano Department of Aerospace Science and Technology Via La Masa 34 20156 Milano, Italy B. Burmann, I. Gerth, M. Scheper OHB System AG Space System Studies Department Universit¨ atsallee 27-29 D-28359 Bremen, Germany I. Carnelli European Space Agency General Study Program Office 8-10 rue Mario Nikis 75738 Paris Cedex 15, France ABSTRACT The Asteroid Impact Mission (AIM) is an ESA mission whose goal is the exploration and study of binary asteroid 65803 Didymos. AIM is planned to be the first spacecraft to rendezvous with a binary asteroid: its mission objectives in- clude the highly relevant scientific return of the exploration as well as innovative technological demonstrations. The paper presents some updates on the ongoing design of the mission. Each phase of the operative life of AIM spacecraft is detailed with information and results on the solutions adopted for Mis- sion Analysis design and on the strategies to suitably operate payloads. The work presented in this paper has been per- formed by the authors under ESA contract within the phase A design of AIM mission. Index Terms— AIM, asteroid, mission analysis, payload op- erations, 1. INTRODUCTION Space missions to small bodies in the Solar Systems are the current hot spot in the space exploration field. The Asteroid Impact Mission (AIM) [1, 2, 3, 4] is an ESA mission whose goal is the exploration and study of binary asteroid 65803 Didymos, which is expected to transit close to the Earth (less than 0.1 AU) in late 2022. AIM is planned to be the first spacecraft to rendezvous with a binary asteroid: its mission objectives include the highly relevant scientific return of the exploration as well as innovative technological demonstra- tions. In addition, AIM is part of a joint collaboration with NASA in the AIDA (Asteroid Impact & Deflection Assess- ment) mission [5, 6, 7]. The primary goal of AIDA is to assess the feasibility of deflecting the heliocentric path of a Near Earth Asteroid (NEA) binary system, by impacting on the surface of the smaller (or secondary) asteroid of the cou- ple. To this aim, AIDA includes the kinetic impactor, DART (Double Asteroid Redirection Test) by NASA [8, 9, 10] and the observer, AIM (Asteroid Impact Mission) by ESA. The work presented in this paper has been performed by the au- thors under ESA contract within the phase A design of AIM mission. The paper presents some updates on the ongoing design of the mission [11, 12]. Each phase of the operative life of AIM spacecraft is detailed with information and results on the so- lutions adopted for Mission Analysis design and on the strate- gies to suitably operate payloads. The selected interplanetary trajectory is presented, including the available launch window to reach Didymos on time. Suitable transfer solutions are se- lected based on Δv constraints imposed by the launcher and further requirements imposed by spacecraft design. More in detail, AIM is planned to be launched in late 2020 and to ar- rive at Didymos system in middle 2022. As the spacecraft approaches the asteroid system, it will go through far- and close- approaching maneuvers. The far-approaching maneu- ver is presented in detail: the final Δv to stop AIM at Didy- mos is split into five smaller maneuvers, performed at one week distance between each other, to decrease the overall ma- neuver cost and to allow for precise tracking and rendezvous with the binary system. Close proximity operations at the as- teroid are then described. During this phase, AIM mission analysis is driven mainly by observational requirements com- ing from scientific payload on board, to study the asteroid sys- tem before and after DART impact (expected for late 2022), such to accomplish mission objectives. Observation stations are selected for AIM spacecraft to study Didymos by operat- ing scientific payloads. As mentioned, Didymos is a binary system: its two components are informally called Didymain (the bigger of the couple) and Didymoon (the smaller one). Close proximity operations include the release of a lander on