Dynamics, Stability and Control of Highly Non-Keplerian Orbits

Families of highly non-Keplerian orbits devised and developed by the applicant have been a principal driver in the recent development of solar sail technology. These new families of novel orbits provide a range of compelling near-term applications for solar sailing and have led to rapid advancement of the technology in Europe and the US. This project will employ a single postdoctoral research assistant for 3 years to conduct a systematic analysis of highly non-Keplerian orbits for spacecraft with low thrust propulsion systems using the methods of modern dynamical systems theory. It is expected that this analysis will uncover new families of orbits for solar sails and solar electric propulsion, again with exciting new practical applications. The UK has a strong industrial interest in low thrust propulsion which will ultimately be strengthened by this programme of fundamental, curiosity-driven research.

The project has delivered a full and detailed understanding of periodic orbits for solar sail spacecraft about artificial equilibria in the circular and elliptical three-body problems. These new families of orbits were found to be significantly different from classical halo orbit families and indeed have many novel applications. We demonstrated that 1 year periodic orbits high above the ecliptic plane provide an excellent platform for polar communications and that formation-flying using neighbouring periodic orbits of equal period can provide a platform for Earth polar observation.

The main findings of the project were reported in some 5 international journals papers and presented at 4 international conferences.

The work undertaken during the EPSRC project led directly to two follow-on projects:

1. European Research Council Advanced Investigator grant (2009-2014) to further explore artificial equlibria and periodic orbits for spacecraft in the three-body problem. We will initially investigate the use of hybrid solar sail/electric propulsion systems to overcome some of the limitations of pure sail systems identified during the EPSRC project.

2. European Space Agency study (2009-2010) to investigate the application of the families of orbits devised during the EPRC project to Mars telecommunications. The project will investigate orbits high above the poles of Mars to provide both polar communication and to provide line-of-sight telecommunications with Earth during solar occultations.