trajectory

Trajectory optimization algorithms for the earth–moon system.

• Open Lunar Foundation

Description

This package hopes to become a repository for Python and Julia tools for optimizing in the Earth--Moon system. It was a work-in-progress when the spacecraft engineering team at Open Lunar Foundation stopped work, so it has never been properly organized. This document attempts to tell where things can be found.

There are two tools in the repository. They are in (mostly) separate branches. The first tool, the Python patched conic cislunar trajectory generator, is in the master branch. It relies on the sequential gradient restoration algorithm to find a minimum delta-v solution. Its usage documentation is below.

The second tool is a Julia tool which solves the same problem using the circular restricted three-body problem. The challenge was to create for a trajectory which roughly copied that of Beresheet, allowing for more robust launch windows and greater flexibility in midcourse maneuvers. This tool is located in branch jared, in the beresheet directory.

See beresheet/README.md in the jared branch for the CR3BP tool's requirements, installation, usage, contribution information, and license.

Requirements

• Python 3.x
• Numpy
• SciPy
• Matplotlib

Installation

Clone this repository:

git clone https://github.com/openlunar/trajectory.git

Currently, this tool cannot be installed as a package. You must run it out of the repository directory. Forward work includes converting it to a package with optimization functions that can be called from other scripts.

To checkout the CR3BP Julia code, do

git checkout jared
cd beresheet/

Usage

Most scripts are in the project root directory. These can be run from a shell, e.g.

python3 trajectory.py

Developers

If you find a bug or wish to make a contribution, use the project's github issue tracker.

License

Copyright (c) 2020, John O. "Juno" Woods, Jared Blanchard, and Open Lunar Foundation. All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
• Neither the name of the nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.