This thesis investigates the availability and optimization of asteroid sequences for a multiple encounter mission with the objective of asteroid characterization and resource determination in the context of an asteroid mining architecture in the main belt. Asteroids are small objects in our Solar System that represent the pristine conditions during the time of the solar nebula with diameters ranging from a few meters up to hundreds of kilometres. They are characterized by their irregular shapes, small masses and the resulting low gravity environment. They are envisaged to support long-term human missions as they contain resources such as water and metals. The objective of this work is to provide a mission architecture for mining infrastructure in the main belt as well as a preliminary spacecraft design for a multiple-encounter mission for asteroid characterization. It gives insights into the availability of and necessary expenses for asteroid sequences and an optimization strategy for flexible target selection. As a first step, a highly autonomous asteroid mining mission architecture KaNaRiA is developed with the objective to make profit with in-space resource extraction. Four operational categories of mission elements are introduced and represented by their own mission elements. The main mission elements are an operational centre in charge of logistics and coordination, maintenance elements for refuelling and repairing, miner spacecraft, transporter and asteroid characterization modules called Titius-Bode. The mission profile and its major events are described. The mission infrastructure is built around a circular, Sun-bound, ecliptic parking orbit 2PO at a = 2.8 AU. All mission elements are characterized with highly autonomous architectures. Furthermore, a mission analysis is performed to optimize suitable asteroid sequences that can be targeted with Titius-Bode depending on its current position and remaining fuel stock. With several hundreds of thousands of objects coming into consideration (JPL small body database: 676390 asteroids, status February 2015), a database pruning strategy based on the spacecraft position the asteroids' current locations is established in order to reduce the number of objects in the database and the computational effort to find a sequence. Using the pruned database, two different solving algorithms for the combinatorial optimization problem are applied to find an asteroid sequence of at least three targets and the results compared. A statistical analysis on the availability of asteroid sequences and their cost in delta v depending on the departure position on 2PO shows that the costs for a three asteroid tour starting from and returning to 2PO range between 1.7 km/s and 2.7 km/s. Next, a preliminary spacecraft design down to sub-system level for Titius-Bode is developed. Its mission objective is to study the physical, chemical and dynamical characteristics of at least three asteroids in a sequence with a focus on the interior composition. Titius-Bode is a composite spacecraft consisting of an orbiter Titius and a lander Bode. Bode is equipped with full manoeuvrability capabilities for asteroid proximity operations that allow the landing and re-docking with the orbiter Titius. For Titius, two design options are presented using high-thrust (HT) and low-thrust (LT) propulsion. In total, Titius’s wet mass sums up to 2636 kg (HT) / 2674 kg (LT) with a delta v capacity of 1500 m/s (each), equivalent to 1865 kg (HT) / 744 kg (LT) propellant. Bode’s wet mass adds up to 254 kg including 43 kg of hydrazine. A detailed trade-off for the HT and LT propulsion capacity and its influence on the total design mass is performed. Subsequently, a concept feasibility for a direct re-entry commodity return capsule (CRC) from 2PO to Earth shows re-entry opportunity windows for a duration of approximately six months each year under the assumption of a maximum re-entry velocity of v_e = 12.8 km/s. For a limit of v_e = 13.05 km/s, a continuous departure from 2PO is possible. A conceptual design of the CRC was presented highlighting the main challenges for each subsystem with a focus on the thermal and planetary protection considerations and the capsule shape. Finally, a cost model for the presented asteroid mining architecture is introduced. Based on expert interviews, 21 cost drivers are identified that alter the total mission costs. A cause-effect analysis called Partial Least Squares Structural Equation Modelling results in an user-individual cost model that allows a first classification of the mission into a cost category.    «

This thesis investigates the availability and optimization of asteroid sequences for a multiple encounter mission with the objective of asteroid characterization and resource determination in the context of an asteroid mining architecture in the main belt. Asteroids are small objects in our Solar System that represent the pristine conditions during the time of the solar nebula with diameters ranging from a few meters up to hundreds of kilometres. They are characterized by their irregular shapes,...    »