Space Mission Planning, Trajectory Design, and Orbit Analysis for the Exploration of Planets, Moons, and Small Bodies of the Solar System

Kurzfassung

This dissertation develops and analyzes scenarios for spacecraft exploration of small bodies, moons, and planets of the Solar System. One focus of this work is on spacecraft orbital motion around asteroids, including binary and triple asteroid systems, as well as motion about planets and about their satellites. Another important focus is on the full mission design and spacecraft transfer scenarios for the exploration of Mars and its moons. In the case of spacecraft motion near small asteroids, perturbing forces such as Solar Radiation Pressure, which may exceed the effect of gravitational forces, must be taken into account. Results are presented for spacecraft motion in so-called “Terminator Orbits” around binary asteroids, such as 1996 FG3. A particularly complex model of the triple asteroid 2001 SN263, involving a main body orbited by two smaller ones, is also investigated. Here, the motion of all three bodies is modeled using a numerical integrator that solves the equations of motion with the various disturbing forces. It is shown that spacecraft in "Self-Stabilizing Terminator Orbits" are potentially stable even within this complex asteroid system. Another focus of this work has been the orbital motion of satellites moving close to and experiencing perturbations from their parent planet, such as in the case of the Martian moons Phobos and Deimos. Here, we studied the dynamic properties and stability of so-called “Quasi-Satellite Orbits,” as well as potential close flybys of the moons and landing approaches. In this context, we also investigated resonant orbits around Saturn’s moon Enceladus, which experiences significant disturbances from its large parent, Saturn. In this context, another study of the orbital evolution and lifetime of the BepiColombo spacecraft was carried out, involving the complexity of the higher-degree and higher-order gravity field of Mercury. Additionally this dissertation presents the development and investigation of a full mission to Mars and its satellite system. This work was carried out in the context of the proposal to ESA (European Space Agency), "Dephine" which aimed to explore the moons of Mars, with a focus on Deimos. This work explored launch opportunities, transfers, and arrival scenarios at Mars. The technical mission concept was developed, including possible data rates and electrical power requirements of the spacecraft. The mission concept was positively evaluated by ESA. Finally, this work studied potential transfer orbits to Mars that included 1.5 revolutions around the Sun, allowing for flybys of the Mars Trojans, targets of high scientific interest. The Martian Trojans share the same semi-major axis as Mars in its orbit around the Sun but are located approximately ±60° ahead of or behind Mars, moving in orbits with relatively high inclinations. A scenario was investigated in which the spacecraft, such as the proposed mission probe Dephine, performed a flyby of a Trojan on its way to Mars. The scenario aimed to minimize additional resources compared to a nominal Mars-only mission. In favorable cases, a small additional delta-v (∆v) of about 0.07 km/s was sufficient to add Trojan flybys to the mission.