In the context of future Human Spaceflight exploration missions, Rendezvous and Docking (RVD) operational activities are mandatory and critical for the assembly and maintenance of cislunar structures . The Orion spacecraft is expected to handle cargo delivery and crew exchange missions that will all require RVD. Despite extensive experience in Low Earth and Low Lunar Orbits, no operational RVD has yet been performed in the vicinity of the Lagrangian points.
The scope of this research is to investigate the specifics of orbits of interest for RVD in the cislunar realm and to propose innovative strategies and trajectory designs to safely perform these kinds of operations. With a focus on Near Rectilinear Halo Orbits (NRHO), previous work has investigated close rendezvous relative dynamics using linear and non-linear targeting algorithms . Current research focuses on far rendezvous approaches and the investigation of passively safe drift trajectories in the ephemeris model. The goal is to exhibit phasing orbit requirements, given a prescribed target orbit, that ensure safe free motion and natural approach of a spacecraft near the target while exhibiting low cost transfer capabilties.
Ephemeris representations of NRHOs were derived using time-varying multiple shooting and adaptive Long-horizon targeting algorithms, resulting in orbit maintenance budgets comparable to those found in the literature . The choice of the Long Horizon parameter appeared to be closely related to the properties of the NRHO and the benefits of an adaptive parameterization of the algorithm was discussed. Simulations showed significant drift and overlapping properties for phasing and target orbits of interest. This motivated the research of safe free drift trajectories with NRHO-like motion in the Ephemeris model, using impact prediction strategies derived from debris avoidance analysis. Such strategies include a local-plane crossing algorithm to perform a quick wide search for potential overlapping sections, later refined by means of screening volumes with probability of collision computations using covariance analysis.
 Stéphanie Lizy-Destrez, Rendezvous Optimization with an Inhabited Space Station at EML2, 25th International Symposium on Space Flight Dynamics, ISSFD, (2015).
 Stéphanie Lizy-Destrez, Bastien Le Bihanc, Sara Manglavitia and Antonino Campolo, Safety Analysis for Near Rectilinear Orbit Close Approach Rendezvous in the Cislunar Realm, 68th International Astronautical Congress, IAC, (2017).
 Jacob Williams, David E. Lee, Ryan J. Whitley, Kevin A. Bokelmann, Diane C. Davis and Chistopher F. Berry, Targeting Cislunar Near Rectilinear Halo Orbits for Human Space Exploration, AAS/AIAA Space Flight Mechanics Meeting (2017).