Research Interest
Astrodynamics
Higher-degree gravity and orbit-attitude coupling
To account for orbit-attitude coupling, the gravitational force and gravity-gradient torque acting on a rigid-body spacecraft must be formulated consistently using spherical-harmonic potential models of arbitrary degree and order. Comparisons with the point-mass approximation quantify the contributions of this coupling, as illustrated by numerical studies around the Moon and a Bennu-like body. These effects become more significant for smaller celestial bodies, particularly for large spacecraft in strongly nonuniform gravitational fields.
Full N-body dynamics, cislunar motion, and binary systems
To account for the mutual gravitational forces and moments of interacting rigid bodies, the full N-body problem (FNBP) should be formulated geometrically on SE(3), preserving the structure of the governing equations under changes of reference frame. Reduction to the circular restricted full three-body problem (CRF3BP) enables investigation of coupled orbit-attitude motion in cislunar and binary-asteroid environments. Applications include Gateway-like near-rectilinear halo orbits and attitude prediction using a full ephemeris model that incorporates the gravitational effects of the Sun and the eccentricity of the Moon’s orbit.
Attitude near periapsis and apoapsis
The CRF3BP simulations examine the attitude motion of a Gateway-like spacecraft near successive periapsis and apoapsis passages. With nonzero initial angular velocity, the body-axis histories illustrate the coupled translational and rotational motion over the first and third passages. The results support investigation of the dependence of near-rectilinear halo-orbit motion on spacecraft inertia and attitude.
Gravity and solar radiation pressure in a binary system
To examine coupled orbit-attitude motion in binary asteroid systems with nearly circular mutual orbits, the CRF3BP can be used to account for celestial body shape and spacecraft inertia, with solar radiation pressure (SRP) included as an additional perturbation. Comparisons of DART spacecraft trajectories near Squannit using point-mass and rigid-body models, with and without SRP, illustrate the influence of these effects on the predicted motion.
References
- McCann & Nazari (2022) · higher-degree gravitational couplingDOI: 10.1007/s40295-022-00335-x
- Nazari et al. (2023) · full N-body theory and CRF3BP reductionDOI: 10.1007/s10569-023-10156-1
- Anderson et al. (2024) · cislunar ephemeris applicationDOI: 10.1016/j.cnsns.2023.107726
- McCann et al. (2024) · binary-asteroid applicationDOI: 10.1007/s10569-024-10180-9
Nonlinear Dynamics, Estimation, and Control
Geometric state estimation and control
To treat orbit and attitude motion within a common framework, spacecraft navigation and mass-property estimation can be formulated on the tangent bundle of SE(3), i.e. TSE(3). The unscented Kalman filter (UKF) uses retraction mappings to represent local sigma-point perturbations on the manifold. The ψ mapping enables simultaneous estimation of spacecraft states, mass, center of mass, and moments of inertia. The comparative navigation results shown here are from the TSE(3) UKF.
Mass and center-of-mass estimation
To identify spacecraft mass properties, reaction-control-system thruster excitation can be combined with a dual UKF on TSE(3). The subsequent square-root formulation incorporates windowing to improve convergence under large initial uncertainties, numerical propagation on SE(3), and an open-loop excitation sequence for parameter identification. The results near perilune show mass and center-of-mass estimates, together with their estimation errors and percentage errors.
Coupled spacecraft–slosh dynamics and estimation
To estimate spacecraft states and propellant mass in the presence of liquid slosh, the coupling between liquid motion and spacecraft orbit and attitude must be considered. A moving, pulsating ball represents the liquid motion, and a square-root UKF on TSE(3) uses retraction mappings for sigma-point propagation and correction. Comparisons of joint and dual estimation approaches under measurement noise and uncertain initial fill ratios assess state and propellant-mass estimation performance.
Orbital motion
Spacecraft attitude motion
Internal slug motion
Fixed Mass and Liquid Mass Comparison — Experimental Testbed
References
- McCann et al. (2024) · ψ mapping and mass-property estimationDOI: 10.1016/j.actaastro.2024.07.011
- Mangiacapra et al. (2022) · geometric UKF and controlDOI: 10.1007/s11071-022-07293-x
- Gunter et al. (2026) · square-root UKF state and mass-property estimationDOI: 10.1007/s40295-026-00634-7
- Fagetti et al. (2026) · joint and dual state and mass estimation with propellant sloshDOI: 10.1016/j.actaastro.2026.03.054
Optimization on Riemannian Manifolds
To account for the geometry of rigid-body attitude and pose, optimization can be performed directly on the manifolds associated with rotation matrices, quaternions, SE(3), and dual quaternions. Gradient and conjugate-gradient algorithms with different step-length strategies are compared in terms of accuracy and computational efficiency. Applications to single-shooting optimal control and pose-equilibrium determination examine the influence of the selected representation and optimization method, including comparisons with constrained Euclidean optimizers.
Constrained pose optimization on SE(3)
To account for position, orientation, and their coupling, static rigid-body optimization can be formulated on SE(3). Riemannian metrics provide the basis for unconstrained optimization and the incorporation of problem-specific constraints. The selected constrained optimization results show the constraint satisfaction criterion and the evolution of position and rotation matrix components over successive iterations.
References
- McCann & Nazari (2025) · Riemannian optimization of attitude and poseDOI: 10.1007/s10957-025-02810-5
- McCann et al. (2024) · constrained and unconstrained optimization on SE(3)DOI: 10.1007/s10957-024-02431-4