NASA Flight Dynamics Analysis

I wanted to create a baseline set of solutions to address potential rideshare opportunities to the Near Rectilinear Halo Orbit (NRHO) regime using NASA’s Artemis III architecture. After doing some research, I realized that the NRHO regime is yet to be fully explored and with the exponential interest in lunar exploration, many companies and government agencies are seeking to establish their presence in this race. Additionally, given the complications of the Circular Restricted Three-Body Problem, there is no general formula or solution to these challenges. This study maintaned a focused on lunar fly-by altitudes between 100-250 km, with a step size of 50 km, and Near Rectilinear Halo Orbit resonances of 9:2, 9:3, 9:4, and 9:5 within the Southern Family of the Earth-Moon L2 point. The goal of this study is to better understand the baseline DeltaV requirements for potential rideshare opportunities of spacecrafts to cislunar space, with a focus on the NRHO regime.

The trajectory design and analysis was performed in Ansys Systems Tool Kit (STK). Given this trajectory accounts for the gravitational wells of two bodies (Earth and Moon), the dynamics of the Circular Restricted Three-Body Problem (CR3BP) were considered and modeled with the Astrogator tool in STK. Solar radiation pressure is not considered for this analysis and spacecraft mass is left at a nominal value of 500 kg. The trajectory design is segmented into two targeting sequences within the Mission Control Sequence (MCS), for a respective lunar fly-by altitude above the Lunar North Pole and NRHO resonance in the Earth-Moon L2 Southern Region.

The launch epoch is 1 Jan 2025 20:39:16.613 UTCG with a burnout altitude of 300 km. The spacecraft coasts for ~50 minutes at 300 km before performing a Trans- lunar Injection Burn (TLI) which sets its trajectory to the Moon. The spacecraft then coasts in Cislunar space for 6 days, approaching the Moon’s Sphere of Influence (SOI) before performing a lunar fly-by at the desired altitude above the Moon’s North Pole. To properly align the spacecraft’s orbit with the desired Near Rectilinear Halo Orbit (NRHO) resonance, a Capture Burn is performed at perilune, and the spacecraft propagates out to apolune of the specified NRHO. The initial conditions of the desired NRHO are derived from NASA JPL’s Three-Body Periodic Orbit Catalog. Lastly, a Near Rectilinear Insertion (NRI) Burn is performed at the apolune of the desired NRHO resonance orbit to ensure the orbit propagates as designed.