publications
Design Analysis for Lunar Safe Haven Concepts
https://doi.org/10.2514/6.2022-1567
Abstract:
NASA’s plan to return humans to the lunar surface faces many challenges, especially in the sustained phases of the Artemis program. In combination with a habitat, a Lunar Safe Haven (LSH) would provide additional protection to crew, electronics, and equipment from the hazards of the space environment such as radiation, thermal extremes, micrometeoroids, and lunar dust. Influenced by the NASA Artemis program goals, the Lunar Safe Haven Study defined the high-level requirements, outlined the trade space for a LSH concept, and evaluated a set of concepts using a decision analysis structure. This paper will provide additional detail for two concepts that were designed and evaluated during the LSH study, the logic behind the choices, and some of the main driving design parameters.
Graphene Solar-Photon Sail: A Novel Approach to the Application of Monolayer Graphene on Aluminized Polyimide Film Using a Figure of Merit for Interstellar Space Exploration
https://doi.org/10.2514/6.2020-3515
Abstract:
Graphene is a one atom thick monolayer hexagonal lattice of carbon atoms with a theoretical thickness of 0.345 nanometers and unique tensile strength capabilities. This study aims to determine how monolayer graphene can be used with an aluminized polyimide film to improve the figure of merit for a solar-photon sail membrane. Monolayer graphene sheets were transferred to polyimide samples and tested for reflectivity and emissivity. The reflectivity was enhanced by graphene and compensated for losses in reflectivity caused by the transfer process. The emissivity data are variable and inconsistent, making the emissivity inconclusive, therefore the polyimide's known emissivity was used. Graphene more than made up for the loss of reflectivity in the transfer process, increasing the initial reflectivity by 14%. Due to this, graphene samples had a significantly higher interstellar cruise velocity than the other groups at the majority of their high sail velocities, even using graphene's lowest possible velocity. Graphene's sail velocity is likely between 6,300 and 19,000 m/s, greater than velocities of the samples without graphene, supporting the conclusion graphene improves solar-photon sail membranes. Graphene's ultimate tensile strength is 1,000 times the strength of the polyimide. Tensile strength should be considered in the figure of merit in future research. This study aims to pioneer the application of graphene for interstellar space exploration and spark future discoveries, discussions, and inventions involving this unique and promising material.