GALLOP
GALLOP – Gravity Assist Low-Thrust Local Optimization Program
Proprietary Low-Thrust Trajectory Optimization Software
© 2008–2025 Chit Hong (Hippo) Yam. All rights reserved.
Overview
GALLOP is a proprietary spacecraft low-thrust trajectory optimization program developed independently by Chit Hong (Hippo) Yam over more than 15 years of research and development.
The software originated during Ph.D. and postdoctoral research (2008–2016) and has been continuously expanded to support:
- Deep-space interplanetary low-thrust missions
- Multiple gravity assist low-thrust trajectory design
- Global trajectory optimization competition (GTOC)
- JAXA's PROCYON and DESTINY+ preliminary mission design
- Cislunar transfers
- Lunar descent and landing trajectory optimization
The source code is private. This Wiki provides public documentation, history, and licensing conditions.
GALLOP
Development Timeline (Key Milestones)
v1.0 – v3.0 (2004–2006)
Early development during Ph.D. and postdoctoral research. Core low-thrust trajectory optimization algorithms established.
v4.0 – v4.5 (2006–2007)
Stable Fortran releases with improved numerical handling and modular architecture.
v5.0 (2008)
Major update introducing XML-based I/O data structures.
v6.0 (2008–2009)
First MATLAB port of GALLOP.
v7.0 (2009-2015)
Added continuous integrated arcs and custom ephemeris support.
v7.1 (2016)
Added minimum/maximum radial distance constraint (“Rmin”).
2017–2025 (private updates)
Cislunar transfer optimization, lunar descent landing tools (not included in this repo).
Academic Reference (Please Cite)
If you use GALLOP for academic research, please cite:
Yam, C. H., and Kawakatsu, Y.
“GALLOP: A Low-Thrust Trajectory Optimization Tool for Preliminary and High Fidelity Mission Design,”
International Symposium on Space Technology and Science (ISTS),
Kobe, Japan, July 4–10, 2015.
Licensing Summary
Academic / Research Use (Free)
- Only for non-commercial research and education
- Requires proper citation
- No redistribution
Commercial / Industrial Use (Paid)
- Required for missions, R&D, analysis, or engineering deliverables
- Internal-use license or project-based license available
- Redistribution, modification, or reverse engineering is prohibited
Copyright
© 2008–2025 Chit Hong (Hippo) Yam.
All rights reserved.
Unauthorized distribution, publication, or commercial use is prohibited.
Contact
For commercial licensing, technical inquiries, or academic access requests: