Research

Dynamics and Control of Distributed Space Systems

  • Optimal formationkeeping, modelling and visualization of spacecraft formations : This research is devoted to optimal formation-keeping of multiple-spacecraft formations, and developing a concomitant  visualization and simulation package for modelling spacecraft relative motion, for applications ranging from rendezvous to long-baseline interferometry.
  • Closed-loop rendezvous and docking: We have been developing autonomous rendezvous algorithms under various perturbations and system faults, such as missed thrust.

Astrodynamics

  • Space situational awareness: We are investigating a few methods for tracking noncooperative objects using various sensors, and study related pose, motion and structure estimation methods.
  • Astrodynamical modelling and control of geostationarry satellites: The increasing lifetime of GEO satellites poses new challenges for astrodynamicists. One such challenge, for instance, is modelling the effect of SRP on the long-term dynamics of defunct communication satellites and space debris; we also develop autonomous station-keeping and collocation algorithms.
  • Long-term behavior of orbits: Using semi-analytical modelling  a myriad of other orbital propagation methods, the goal is to determine the long-term faith of natural and artificial satellites orbiting various planets and moons.
  • The restricted three-body-problem: Mars, Phobos, Deimos: Where are the Lagrangian points located? Do they exist under solar gravity? How to escape/collide with the Martian satellites?

Orbit Propagation, Control and Optimization

  • Variational integrators: It can be shown that variational transformations exhibit symmetry which may be utilized to reduce the local integration error of the Runge-Kutta method. We are still looking for the best variational method.
  • Resonant control of orbits: Can an artificial resonance, created using low-thrust profile modulation, be efficient in orbit control, rendezvous and low-thrust transfers?