Continuous low thrust propulsion can add considerable utility to spacecraft dynamics by enabling rich new families of thrust augmented orbits. With the aim of enabling such orbits for small, lowcost spacecraft with limited onboard sensing, new families of nonKeplerian orbits are generated in the HillClohessyWiltshire approximation using positiononly feedback. The same strategy is also applied to the linearised dynamics around collinear libration points in the circular restricted threebody problem. In the EarthMoon system, positiononly feedback is used to stabilise the local dynamics, and interesting new multiplyperiodic orbits are generated. The inplane and outof plane natural frequencies are then synchronised, allowing the generation of stable halotype orbits of arbitrary dimensions. An application for such orbits, an EarthMoon L2 communications relay, is also suggested. The propellant requirements for such orbits are shown to be modest and achievable with existing low thrust technology. Continuous thrust is also used to produce artificial horseshoe orbits in a two body system. Using the cylindricalpolar form of the HillClohessyWiltshire approximation, low thrust manoeuvres are developed which allow for phased, nested constellations of spacecraft around a circular twobody orbit. Interesting new threedimensional nested constellations can be enabled by the addition of out ofplane thrust, offering reconfigurable coverage of specific regions of the Earth. In the circular restricted threebody problem, constant thrust directed along the unit radius vector from each primary mass is applied to a spacecraft, modifying the positions and nature of the five equilibrium points, and thereby changing the region in which horseshoe orbits can occur. In the 243 Ida binary asteroid system, it is found that acceleration directed towards the two primaries results in Lyapunovstable L4 and L5 points, permitting horseshoe orbits. In the 243 Ida system, a strategy is then proposed for finding periodic horseshoe orbits which rendezvous with the surface of the smaller primary. A search andfilter method is employed to produce initial guesses for periodic horseshoe orbits, and these guesses are then refined using a numerical shooting method to find precisely periodic orbits. However, this method misses periodic orbits with more than two crossings of the axis connecting the primaries, and is therefore modified to provide guesses for horseshoe orbits with additional crossings. Using this strategy, two thrust augmented horseshoe orbits which rendezvous with the surface of the smaller primary are found, and the speed of the spacecraft at rendezvous is shown to be small. Such orbits offer interesting new opportunities for binary asteroid touchandgo sampling.
Date of Award  21 Sept 2018 

Original language  English 

Awarding Institution   University Of Strathclyde


Sponsors  EPSRC (Engineering and Physical Sciences Research Council) & University of Strathclyde 

Supervisor  Malcolm Macdonald (Supervisor) & Colin McInnes (Supervisor) 
