Towards Minimal Energy Sensor Deployment in Exo-Atmospheric Environments

We propose BOLAS, or Break-Off and Landing Sensing, as a prospecting mobility solution concept capable of deploying individual instruments, such as a miniature spectrometer or a freefall penetrometer, to the base of a Permanently Shadowed Region (PSR) of the Lunar South Pole. Our overall approach to prospecting mobility is to use a projectile 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 paper presents proof-of-concept dynamics simulations that demonstrate the impact velocity minimization properties of the BOLAS system.