~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ON ASTEROID RETRIEVAL MISSIONS ENABLED BY INVARIANT MANIFOLD DYNAMICS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~
~ This repository is curated by Jack Tyler; for any queries, or additional data 
~ requests, contact jack.tyler@soton.ac.uk
~
~
~ PUBLICATION DETAILS
~ ~~~~~~~~~~~~~~~~~~~
~ On asteroid retrieval missions enabled by invariant manifold dynamics. Acta Astronautica, 2021. https://doi.org/10.1016/j.actaastro.2021.03.002
~
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~ INTRODUCTION
~ ~~~~~~~~~~~~
~ This repository contains codes and results that produced `On Asteroid Retrieval Missions Enabled by Invariant Manifold Dynamics'.
~ For any other queries, or any further data requests, please contact me at the email above.
~
~ FILE STRUCTURE
~ ~~~~~~~~~~~~~~
~ There are two sets of files in this repository: main.zip and supplementary_ephemeris*.zip. The former contains the 'core' material needed to reproduce this work.
~ The latter is included for convenience only, and provides pre-downloaded orbital ephemerides for the entire NEO database as of February 2020. This is to prevent
~ you needing to acquire these from HORIZONS. These are kindly provided by NAIF (naif.jpl.nasa.gov), and I hold no claim to this data. Be aware that the ephemerides are heavily compressed
~ and require nearly 30GB of storage!
~
~ FOLDER STRUCTURE: MAIN.ZIP
~ ~~~~~~~~~~~~~~~~~~~~~~~~~~
~ codes/: Contains the `Fortran Asteroid Retrieval Toolkit', a collection of (mostly Fortran) tools used to generate all the results in this paper.
~         Included in the folder is README.md, which contains all the instructions required to build, configure and run the programs. A Fortran, C and C++ compiler
~         is required, along with support for the MPI parallel programming paradigm. If you wish to use the automated script to download ephemerides from JPL HORIZONS, you will also
~         need a valid Expect interpreter.
~ ephemerides/: Contains a planetary ephemeris (DE430S) and a leapseconds kernel (latest_leapseconds.tls) downloaded from naif.jpl.nasa.gov for convenience. If you would
~               would also like to download all the SPK files for all the NEOs present at the start of our study (Feb 2020) from here rather than use the JPL HORIZONS service,
~ 		then the supplementary_ephemeris*.zip files in the ePrints server to download all the ephemeris we used.
~ pareto_fronts/: Results files for all the Pareto fronts for all of the EROs found. More detailed instructions on the structure of each of the files is included in a README in the folder.
~ prefilter_results/: Contains the results of the pre-filtering (pruning) routines. More detailed instructions on the structure of the files is included in a README in the folder.
~ transfer_details/: Contains two files with details on the retrieval trajectories found: just_eros.tex is the same as presented in the paper and gives the Delta-v optimal transfers for all
~                    the EROs found. all_table.tex contains the Delta-v optimal transfers for all the retrieval candidates (ero_table.tex is a subset of all_table.tex).
~
~ If you would like more data than is provided here, or are unsure on e.g. how to use the Fortran codes, do not hesitate to get in touch. 
~ Equally, if you found this work useful or interesting in any way, please let me know.
~
~ Best wishes,
~
~ Jack Tyler
~
~ Nov. 10, 2020.
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