TEST-RAD is a novel regolith mitigation technology intended for use on various systems deployed on the lunar surface, particularly junctures in apparatuses and moving components of spacesuits. Inspired by the dense fur of a chinchilla and incorporating preexisting electrostatic technologies, our design utilizes biomimicry for passive protection and active same-charge repulsion of regolith. This hybrid passive-active system will reduce the penetration of regolith into closures or seals of a given apparatus by repulsion via conductive fibers and last-resort catching fibers.
The system is composed of six parts: charged fibers, catching fibers, metal mesh, insulative backing, charging wires, and an ionization device. An outer layer of tufted charged fibers repels same-charged regolith. Short catching fibers, placed along the internal edge and only exposed in the event of opening of the seal or closure act as a secondary layer of defense, catching regolith particles that get near the surface of the seal or edge. Both fibers are tufted through a copper mesh with charging wires from the ionization device to provide the system with a static charge. An insulating backing connects TEST-RAD to the apparatus and insulates it from the protected equipment.
TEST-RAD’s technology acts as a hybrid mitigation device providing both a passive barrier to lunar regolith, as well as an active electrostatic component that assists in repelling any charged lunar regolith. TEST-RAD aims to increase astronaut health and safety, decrease cleaning time, and reduce the harm done to equipment by regolith.
TEST-RAD is a layered defense system, combining two technologies intended to stop the penetration of regolith into fabric, seals, and internal surfaces. It uses electrostatic shielding combined with a novel bio-inspired tufted fiber to repel same-charge particles. Electrostatic shielding had already been proven for the repulsion of lunar dust (Calle et al., 2008). However, due to the variation in regolith size and shape, this mitigation technique alone is not enough to fully protect the joints and moving mechanisms, seals, edges, and openings of devices from being compromised by regolith. Our addition of densely packed fibers to block out sharp dust particles, within the given size range, aims to provide a complete solution. Inspired by the densely packed fur of the chinchilla, the tufted fibers will provide a physical barrier between the electrostatic generation assembly (EGA) and the regolith. This hybrid approach to mitigating regolith proliferation results in TEST-RAD being cost-effective and easy to implement on both established and future technologies. Adhering TEST-RAD to the outside surfaces of equipment requires little to no design modification. 
The conductive tufted fibers are made from Liberator®­­­, Vectran™ by Kuraray, a multifilament yarn spun from liquid crystal polymer (LCP). The tufting process creates an array of dense, durable fibers carrying the same charge as the regolith, extending the electrostatic field, and decreasing the rate of dust accumulation. Regolith adhesion to exposed seal surfaces is greatly reduced by the application of the charged fiber system. If the fibers become saturated with dust, it will not cause the system to fail and occasional brushing of the fibers will provide sufficient cleaning to improve the longevity of the system.
Shorter catching fibers are arranged in a single row along the seal abutting edge. These catching fibers are only exposed during seal opening and closing and act as a secondary layer of defense, catching the regolith particles that get near the surface of the seal or edge. However, during donning and doffing of the EVA suit, regolith particles will be shaken loose, potentially bypassing our charged solution, but not the catching fibers. Other opening and closing operations for alternative applications will present similar risks, but any regolith particles that land along the seal-abutting edge of TEST-RAD will be caught by the row of catching fibers. These catching fibers are composed of polyester, commercially used in fish tanks or woodshop filters.
Both fibers are tufted through a copper mesh with charging wires from the ionization device attached to provide the system with static electricity. This serves as a medium for the electrostatic charge to pass through, as well as providing the necessary structure for fiber tufting. Prototypes used a copper expanded mesh with 3.2 mm holes. This mesh is one of the three major components of the EGA, with the other being an ion generator connected to the power supply of the life support system and a delivery wire. The power system supplies TEST-RAD with the required electrostatic charge to functionally operate. TEST-RAD is insulated and attached to equipment via a Kapton film backing.
TEST-RAD meets specifications for temperature tolerances and is non-toxic and non-out-gassing. Per 1 cm length test rad has a linear density of 1.45 ± 0.01 g/cm. Conductive fibers have a height of 1.30 cm ± 0.01 cm and catching fibers have a height of 0.50 cm ± 0.01 cm. Per 1 cm of width, or 5 rows, TEST-RAD fibers spread out to 2.25 ± 0.01 cm width at its height. At its current state of development, the material costs to prototype the first 10 cm TEST-RAD amount to $528.74 and each additional centimeter costs $0.24.
At the initiation of the EVA, the life support system is activated, causing an electrostatic charge to be applied to TEST-RAD and maintained, resulting in the repulsion of regolith from sensitive areas. One concern of the Artemis mission, and longer duration EVAs, is the variation in regolith charge depending on whether it is lunar day or lunar night. The system is effective in either of these situations, as the electrostatic field generated by TEST-RAD is large enough to repel dust particles independent of regolith polarity. This concept has been proved by the NASA Electrostatics and Surface Physics Laboratory and TEST-RAD will be developed to reproduce a similar level of success.
Verification of The technology was conducted within a glove-box inert gas chamber environment using high-fidelity simulants throughout the prototyping and testing processes. TEST-RAD was tested within the chamber and was subjected to various regolith mitigation tests. Tests on the system showed that the mean distance repelled was approximately 23 cm of particles in the 50 - 0.5 μm range. Additionally, testing showed that, at a distance of about 3 cm from simulant, TEST-RAD could repel a mean of approximately 30% of simulant in that same particle size range. These tests also had a maximum average value of 29 cm repelled, and an average maximum value of 66% repulsion at a distance of approximately 3 cm. The failed seal test, meant to illustrate a non-ideal seal, showed that TEST-RAD is more effective at keeping dust out of a seal area compared to no protection. We believe these results indicate that TEST-RAD is a versatile dust mitigation device, which can then be integrated into various Artemis instruments.
Our team also sought to find potential applications of TEST-RAD outside of the initially designed use case. Our project was originally intended to be placed on the spacesuits of NASA’s Artemis mission. However, if TEST-RAD cannot be put onto the xEMU suits or the commercial suits flown on early Artemis missions, we considered other applications where the use of the technology is appropriate and valuable. Some suggestions from the BIG Idea administration included gearbox covers and soft-wall habitats.
We also explored several other locations TEST-RAD could be useful: the VIPER battery cover, VIPER gearbox cover, and the mirror and lenses of mission cameras. The goal was to find closures, seals, and other appropriate edges and junctures on equipment that have an unresolved need for regolith mitigation. The decision was made to use TEST-RAD as a strip to ensure adhesion, coverage, and flexibility. This flexible tape-like format also allows versatility in application.
A promising alternative application of TEST-RAD is along the seam of the Volatiles Investigating Polar Exploration Rover (VIPER) battery cover. Regolith has the possibility of causing the battery to overheat either through permeation through junctions, or creating a film over surfaces, causing a larger system failure. Previously, there were no specific dust mitigation protocols, meaning astronauts had to manually brush regolith off the radiators. TEST-RAD would be applied as a dust mitigation strategy and would line vulnerable seams and junctions of the battery cover, preventing dust permeation and potentially the formation of a regolith film over battery surfaces. The wiring would also be connected to a central control board on a control panel within the astronauts reach.
TEST-RAD could also be applied to gearbox covers on the VIPER to prevent regolith-induced wear and tear. All junctures on the gearbox used for service access, or areas with vulnerable edges, could benefit from this application. Our Mark 4.1, which reaches an IP 67 rating, junction box test approximates the scale and application type to be used on the VIPER.
TEST-RAD can also be applied at the cameras monitoring crater formation below the lunar lander. After researching many different lunar camera systems, the SCALPSS Camera appeared to be the most at risk. These cameras, designed to film the lander crater and landing thrusters during landing, are bombarded with regolith. Thrusters launch particulates off the Moon's surface making these cameras particularly at risk. In addition, their data is internally stored and only physically accessed after landing.
More information on verification testing can be found in the published technical document.

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