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Examining the Feasibility of Relative-Only Navigation for Crewed Missions to Near Rectilinear Halo Orbits

August 25, 2022

Recently, lunar Near Rectilinear Halo Orbits (NRHO) have been the focus of much study, and they have been selected as the target orbit for the Gateway mission, formerly the Deep Space Gateway. Also, the Deep Space Network (DSN) is increasingly congested and over-subscribed. In this work, the performance of relative-only navigation between a spacecraft in an NRHO and a relay in a Distant Retrograde Orbit is examined and compared to simulated DSN tracking using a Square Root Information Filter. Various tracking scenarios are examined using a closed-loop simulation where navigation errors inform maneuver planning and maneuver execution errors affect navigation performance. Results indicate that relative-only navigation can provide comparable levels of orbit determination error and orbit maintenance costs.

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Distant Retrograde Orbit Constellations for Relative-Only Navigation in Near Rectilinear Halo Orbits

July 27, 2022

NASA is currently working on the spacecraft and trajectory design for the Gateway mission that will reside in a Near Rectilinear Halo Orbit (NRHO). In the NRHO, Gateway will nominally require orbital maintenance maneuvers once per revolution. Separately, NASA is also working to develop technologies and techniques for relative navigation in cis-lunar space. Together, these concepts represent an opportunity for interesting research in cis-lunar navigation performance.

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Survey of Ballistic Lunar Transfers to Near Rectilinear Halo Orbit

June 29, 2022

This paper provides a thorough review of how ballistic lunar transfers (BLTs) can be used to transfer from Earth to near rectilinear halo orbits (NRHOs) in an efficient manner.

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Heliocentric Escape and Lunar Impact from Near Rectilinear Halo Orbits

May 17, 2022

Spacecraft departing from the Gateway in a Near Rectilinear Halo Orbit (NRHO) experience gravitational forces from the Moon, the Earth, and the Sun, all of which can be simultaneously significant. How do these celestial objects influence the trajectory of spacecraft? Find out more by reading this white paper.

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NASA Conjunction Assessment Risk Analysis Updated Requirements

March 28, 2022

The NASA Conjunction Assessment Risk Analysis (CARA) program has been performing routine on-orbit satellite conjunction risk analysis for unmanned NASA spacecraft since 2005, and has developed a robust operations procedure and set of recommended best practices for operational conjunction assessment. Read this article to learn more about the CARA program's updated requirments.

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L2 Station Keeping Maneuver Strategy for the James Webb Space Telescope

February 14, 2022

The L2 station keeping plan for the James Webb Space Telescope achieves zero velocity in the x-component at the fourth successive crossing of the XZ plane of the rotating libration point frame. The techniques developed to determine the minimum maneuver direction in a full ephemeris model, along with strategies to cope with the attitude constraints imposed by the sunshield that prevents the ability to maneuver along the stable eigenvector, are examined in this study.

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Cloud Computing Methods for Near Rectilinear Halo Orbit Trajectory Design

January 25, 2022

Trajectory analysis in the presence of multiple gravity fields is complex, and innovative computational tools are needed to simplify complicated design spaces, generate large quantities of data quickly, and visualize the output for user accessibility. Explore the tools required for success.

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