PhD Thesis Proposal: Philip Mulford

For info on how to attend this videoconference, email philip.m.mulford.jr.th@dartmouth.edu.

"Minimal energy deployment of remote sensing platforms in low atmosphere environments"

Abstract

The regions of the Moon most promising for human use are also the regions that are the least studied. Lunar Permanently Shadowed Regions (PSRs) exhibit characteristics, such as steep descent angles and porous regolith, that make rovers a sub-optimal exploration tool. However, they also harbor some of the greatest concentrations of useful ices, such as ices composed of water, N₂, CH₄, Argon, or Xenon.

This proposal defines a novel solution that utilizes a launcher from the rim of a PSR to launch BOLAS which comprises two spheres connected by an elastic tether. One sphere contains a sensor payload to be deployed (the "science sphere") and the second counter sphere serves as a "sacrificial" mass. The sequential launching of each sphere with individual target velocities sets up a rotation when the tether is in tension. The landing velocity of the science sphere in a vacuum is controlled by detaching the sacrificial sphere such that the kinetic energy of the science sphere is sufficiently low to survive impact. In this way, a controlled landing is implemented passively, without external actuators, such as a solid rocket.

Our mission scenario and mobility concept focus on acquiring data to answer questions about PSRs, such as: Does the regolith support mobility? What is the distribution of volatiles within PSRs? At the expected landing velocity, the science sphere can act as a free-fall penetrometer embedding in the regolith. Its acceleration profile as it embeds and comes to rest can be analyzed to estimate the geotechnical properties of the regolith that are important for assessing both traditional vehicle mobility and energy needed to mine the regolith for in-situ resources.

This proposal covers the development of dynamics simulation for a 2-body tethered system in minimal-atmosphere environments, proposed sensing methodologies required to estimate the state of the system as it travels, the development of a launch model to aid in that state estimation, and the extension of the BOLAS system to 3 or more spheres.

Thesis Committee

• Laura Ray (Chair)
• Minh Phan
• Solomon Diamond
• Benjamin Hockman (external)

Contact

For more information, contact Theresa Fuller at theresa.d.fuller@dartmouth.edu.