HSL Meeting: Alex Miller, Mike Brown (HSL) (12-1p, 2/27, Rm 31-270)

HSL Meeting

Monday, February 27, 2023
12-1pm
Room 31-270

Zoom link: https://mit.zoom.us/j/99313053821

 

Talk #1: 

  • Speaker: Alex Miller 
  • Title:  Design Development of a Stable, Lightweight, Tall and Self-Deploying Lunar Tower
  • Abstract—Deployable composite booms with spaceflight heritage are being investigated at the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) and the Massachusetts Institute of Technology (MIT) Space Resources Workshop for their potential to be vertically deployed in the lunar gravity field, in support of the NASA Artemis campaign. This paper reports new design development results—after the original presentation at the NASA 2020 BIG Idea Challenge—for a 16.5-meter-tall, compact, self-deploying composite tower intended to support the exploration of lunar permanently shadowed regions by nearby robotic assets or humans. Possible applications include vertical solar arrays and the provision of elevated lines-of-sight to science or engineering payloads, in support of nearby targets operating in areas of interest that may be hard to reach. Useful elevated payloads include radio repeaters, remote sensing and imaging, navigation and power beaming systems. However, while these lightweight rollable booms have an excellent height to mass ratio, they typically exhibit axial curvature upon deployment resulting in appreciable lateral dead-load deflection of the tip mass relative to the tower base. This static deflection increases with tower height and tip mass, not only constraining the value delivered by the tower but also endangering its integrity. To develop a competitive, lightweight deployable composite boom tower, a capability to correct static deflections during and after deployment will be required. In this paper, a deployable guy wire stability system will be presented for the MIT / LaRC self-erecting composite boom lunar tower that provides real time measurements, maintains tension both actively (during deployment) and passively (post-deployment), and can serve as a reconfigurable platform to test and trade alternative stability system configurations, such as with added spreaders inspired by sailing boat masts. Using a calibrated photogrammetry system, the natural lateral deflection of the boom tip relative to the boom base at different deployed heights was recorded for different configurations. With real-time force measurements it was found that tensioned guy wires can significantly reduce the static tip deflection of a deployable composite boom under dead load and can dampen a dynamic oscillation in under a minute. It was also found that control authority is greatest where it is needed most, i.e., for the lever arm closest to being opposite the direction of deflection. For a tower height of at least 11 m and spreader length of at least 60 cm, a solution of differential tension in all three arms exists and, in principle, provides sufficient control authority to correct or significantly reduce boom tip deflections. Notably, natural deflections occur almost entirely normal to the seams of the boom cross-section, but the natural boom tip lateral deflection 978-1-6654-9032-0/23/$31.00 ©2023 IEEE under dead load upon deployment was approximately 5% of boom deployed length, exceeding the manufacturing acceptance specification of 1%. Ongoing and future work includes the further investigation towards mitigating manufacture-caused lateral deflection, trading of alternative guy wire system designs, as well as the design development of a second-generation tower incorporating a more capable boom design with the learnings from the proof-of-concept system presented here.

Talk #2: 

  • Speaker: Michael Brown
  • Title: WORMS: Field-Reconfigurable Robots for Extreme Lunar Terrain
  • Abstract—The 2022 NASA BIG Idea Challenge invited teams to develop novel extreme lunar terrain mobility technologies in support of the Artemis program, setting only the constraint to not propose a wheeled robot. This paper proposes a platform for field-reconfigurable walking robots that can be tailored to multiple missions and repaired in the field. We synthesized several locomotion methods into our field-reconfigurable robot platform architecture, the Walking Oligomeric Robotic Mobility System (WORMS). The elements of WORMS include identical articulating Worm robots, simple Accessories, such as shoes, and more sophisticated Species Modules. With a variety of elements in hand, different animal-like robots can be rapidly assembled and dispatched to support many different mission profiles. In our WORMS-1 proof of concept presented here, six Worms with large Apollo-like shoes serve as legs to traverse high-porosity and steeply inclined terrain to set up a charging and radio relay station for other rovers inside permanently shadowed regions. WORMS is enabled by three key technologies: (1) the Worm robot itself; (2) the universal interface block (UIB) which is a common mating adapter for all mechanical, electrical, and data connections between Worms, Accessories, and Species Modules; and (3) the ability to safely share electrical power between Worms. In the paper, we present the architecture, trade studies, test results, and path-to-flight considerations for evolving the as-built proof of concept WORMS-1 from its current Technology Readiness Level (TRL) 4 into a future TRL 6 design. We propose that WORMS is a resilient, easily maintainable, low-cost, evolvable, flexible, future-proof, and modular architecture for the rapid field assembly of robots to support extreme terrain access and lunar infrastructure development.