This report presents an investigation into preliminary transfer orbit determination and sets calculation procedure for it. The objective is to calculate high-energy transfer trajectories between two circular orbits satisfying the given conditions and determine the required transfer time, total time to rendezvous and propellant mass.
The objective of the thesis is to find all possible orbital transfers, other than the Hohmann transfer, and determine the flexibility in performing the rendezvous. Although, the Hohmann Transfer is the most energy-efficient solution, the time of transfer can be significantly reduced at the cost of increasing propellant. Determining alternative trajectories would help improve the mission flexibility by increasing the number to opportunities to perform successful rendezvous and reduce the overall time to rendezvous.
Lambert algorithm was used to calculate the transfer trajectories. This algorithm is used extensively in celestial mechanics and proved to be accurate and easy to implement. As it uses the universal variable approach for solving a two-point boundary problem, it can be applied to orbits of any shape. Therefore, it will be possible to increase the complexity of the problem using the same algorithm and accounting for perturbations due to atmospheric drag.
The calculated trajectories proved that re-orientation of the chaser on the parking orbit prior to firing and injection thereof into a non-tangential transfer orbit required large changes in velocity and therefore large amounts of propellant. It resulted in a comparatively narrow range of suitable trajectories that the vehicle was capable of performing at each specified time of flight. Nevertheless, due to available range of transfer times, it was calculated that almost half of the parking orbit could be covered. It significantly increased the opportunities to perform successful rendezvous under the transfer times much shorter than that of Hohmann transfer.