College - Author 1
College of Engineering
Department - Author 1
Mechanical Engineering Department
Degree Name - Author 1
BS in Mechanical Engineering
College - Author 2
College of Engineering
Department - Author 2
Mechanical Engineering Department
Degree - Author 2
BS in Mechanical Engineering
College - Author 3
College of Engineering
Department - Author 3
Mechanical Engineering Department
Degree - Author 3
BS in Mechanical Engineering
College - Author 4
College of Engineering
Department - Author 4
Mechanical Engineering Department
Degree - Author 4
BS in Mechanical Engineering
Date
6-2022
Primary Advisor
Peter Schuster, College of Engineering, Mechanical Engineering Department
Abstract/Summary
To support NASA’s upcoming Artemis missions, an extravehicular activity (EVA) photometric calibration scale was developed to replace the Apollo-era Gnomon device. The Gnomon was a gimbaled stadia rod mounted on a tripod which provided color and reflectivity photo calibration, vertical orientation, and solar shadow direction, to include in photos of lunar geologic samples and features. With over 50 years of innovation since the first Gnomon deployment on Apollo 11, this redesign of the photometric calibration scale will support NASA’s missions in the modern day. The Tholos™, named after the ancient Greek repository of standardized measures, consists of a quadrupedal design with low center-of-mass, ensuring high stability at steep angles. The design contains a telescoping extendable stadia rod at its center. The stadia rod slides out of the protective sheath to provide color, greyscale, and linear measurement calibration targets. An attached reflective 360° prism provides accurate polar line of sight position information when used with a ground-based transit theodolite with electronic distance measurement. The Tholos™ can be operated, deployed, and retrieved while standing and can be stored within the provided 2” x 4” x 15” volume when collapsed. The deployment and retrieval of the Tholos™ is compatible with the limited dexterity of an EVA suit. The design uses flight-like materials that were selected for optimal mass, stiffness, fracture criteria, resistance to lunar dust abrasion, and ease of manufacture. Additionally, the Tholos™ unit’s materials can be modified for Neutral Buoyancy Lab (NBL) testing. As such, the design satisfies all requirements imposed by the Micro-g NExT competition in an effective manner. Final testing showed that the design was operable with EVA gloves and fit all necessary NASA criteria.
URL: https://digitalcommons.calpoly.edu/mesp/684