View source for Lecture: In-Space Transportation including Cis-Lunar Trajectories


This lecture summarizes the basics of orbital mechanics - starting from the Earth's surface - and how to move within and outside the Earth's Sphere of Influence (SOI), including the "patched conics" approach for lunar missions. Some links to more advanced concepts such as the Near Rectilinear Halo Orbit (NRHO) around the Moon that is being considered for the Lunar Gateway are provided.

[[File:In-Space-Transportation.pdf]]

The following recent paper explains what are Halo Orbits and how to compute then numerically. The proposed NRHO for the Lunar Gateway is a subset of the family of all possible Halo orbits.

[[File:IAA-AAS-DyCoSS3-125.pdf]]
Emily M. Zimovan, Kathleen C. Howelly, and Diane C. Davis
NEAR RECTILINEAR HALO ORBITS AND THEIR APPLICATION IN CIS-LUNAR SPACE

Besides the NRHO orbit an important class of orbits are those from the Earth to the Moon (LEO-LLO) using not the patched-conic planar approximation but numerically solving the restricted three body problem (CR3BP). The following trajectories and tradeoff between Delta-V and time of flight (TOF) is found based on Dr. Thomas Coffee's recent doctoral thesis at MIT.

[[Image:CR3BP.jpg | 600px ]]

These [[file:TMC-thesis.pdf]] trajectories particularly in the lower right corner can be interesting for non-time critical cargo transfers that may take about 100 days or so. The typical Hohmann transfer to LLO takes about 3-4 Earth days.