Comparison of Numerical Methods for Low-Thrust Spacecraft Trajectory Optimization
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Low-thrust spacecraft propulsion systems enable fuel-efficient trajectories through space but the resulting trajectory optimization problems can be challenging. In this work, various numerical approaches for designing such low-thrust trajectories have been analyzed and compared. First, the Hermite-Legendre-Gauss-Lobatto (HLGL) and the Legendre-Gauss pseudospectral (PS) direct collocation methods, which are used for transcribing an optimal control problem into a nonlinear programming problem, have been compared for a minimum-time low-thrust Earth-to-Mars transfer problem. Next, a novel control law, the RQ-Law, is presented for generating low-thrust three-dimensional multi-revolution coasting-enabled rendezvous trajectories with a moving target, based on modified equinoctial elements. It builds upon the Q-Law, which is a Lyapunov feedback control law for orbital transfers. The RQ-Law offers an alternate method of determining the Lyapunov-optimal thrust angles used for both orbital transfer and phasing. It also provides a new target semimajor axis augmentation scheme that is demonstrated to perform phasing in a wide range of eccentric orbits. Compared with existing low-thrust Lyapunov rendezvous methods, the RQ-Law can include coasting arcs in the trajectory to save fuel as well as account for a minimum periapsis radius constraint. Alongside a thorough qualitative comparison of the RQ-Law, the performance of this law is evaluated numerically by using it to generate a rendezvous trajectory involving large changes in all six orbital elements. This performance was compared with a hybrid control law composed of an existing modified equinoctial Q-Law and a spiral phasing law. Three trade studies were performed that studied, respectively, the effects of the chaser departure point, the point at which low-thrust phasing is initiated, and the target orbit eccentricity, on the RQ-Law performance. Finally, to investigate the use of the RQ-Law to help mitigate the problem of space debris, we develop a low-thrust multiple-rendezvous trajectory to traverse a predetermined sequence of targets. The RQ-Law advances the state-of-the-art of the Q-Law and provides an integrated design tool for preliminary low-thrust rendezvous trajectory generation without needing an initial guess. The contributions of this thesis can be used for a variety of planetocentric and interplanetary space missions that use low-thrust electric propulsion.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it