Astronauts will be tracking dust into the Lunar Gateway. Is this a problem?

Lunar regolith (aka. moondust) is a serious hazard for missions heading to the moon. It is in every single place on the floor—5 to 10 meters (~16.5 to 33 toes) in depth in some locations—to not point out jagged and sticky. Through the Apollo missions, astronauts realized how this dust adhered to every thing, together with their spacesuits. Worse, it will get tracked again into their lunar modules (LMs), the place it caught to surfaces and performed havoc with electronics and mechanical tools, and even led to long-term respiratory issues.

It is a main concern for the Artemis Program, which goals to ascertain a “sustained program of lunar exploration and improvement.” One of many key parts of this program is the Lunar Gateway, a lunar habitat that may orbit the moon for a deliberate 15 years and facilitate long-term missions to the surface. The impression that regolith launched by astronauts coming back from the floor may have is just not effectively understood. In a latest paper, a NASA-led crew of researchers created a physics-based mannequin to asses how regolith might impression the habitat over time.

The crew was led by Ronald G. Lee, the lead aerospace engineer with Houston-based consulting, analytics, and authorities/army contractor Booz Allen Hamilton. He was joined by scientists from NASA’s Johnson House Heart, NASA’s Marshall House Flight Heart, the ESA’s European House Analysis and Expertise Heart (ESTEC), and Houston-based engineering agency Jacobs Expertise and aerospace contractor Barrios Expertise. The paper that describes their mannequin not too long ago appeared in Acta Astronautica.

Whereas most meteors getting into Earth’s environment deplete earlier than reaching the floor, the moon is an airless setting. In consequence, billions of years of impacts have pulverized the floor, producing effective silica particles. The absence of an environment additionally meant that these particles skilled no weathering from wind or precipitation, leaving them misshapen and jagged. The interplay between these particles and charged plasma from the sun’s corona (aka solar wind) has left the regolith electrostatically charged, inflicting it to stay to electrically charged surfaces.

This dust triggered quite a few issues in the course of the Apollo missions, together with thermal management problems with the Lunar Reconnaissance Car’s (LRV) batteries in the course of the Apollo 16 and 17 missions. Eugene Cernan, Commander of the Apollo 17 Mission, went so far as declaring lunar regolith to be the best problem to lunar exploration. “I feel dust might be one in all our best inhibitors to a nominal operation on the moon,” he stated. “I feel we are able to overcome different physiological or bodily or mechanical issues besides dust.”

Within the coming years, the Artemis Program will ship astronauts to the moon for the primary time because the Apollo Period. However in contrast to the earlier crewed landings, which left behind numerous science experiments and “footprints and flags,” the Artemis Program will set up lasting infrastructure. Along with the Lunar Gateway, astronauts will depend on the Artemis Base Camp whereas performing science operations on the floor. The ESA and China even have plans for lunar infrastructure, referred to as the Lunar Village and the Worldwide Lunar Analysis Station (ILRS), respectively.

This implies a number of space companies and business companions launching to and from the floor and astronauts performing common extravehicular actions (EVAs). The quantity of lunar regolith kicked up and tracked again to autos and habitats will trigger put on and tear on spacesuits and autos, being so extremely abrasive. It should additionally play havoc with equipment, power systems, life help techniques, and different very important elements. There are additionally the well being dangers that airborne regolith will pose to astronauts, business crews, and lunar vacationers.

The scenario shall be considerably extra difficult because of the presence of a number of interacting mission parts. As they wrote, “The distinctive problem posed to Gateway is it won’t endure a one-time publicity to lunar dust, akin to was probably the case with Apollo Command and Service Modules, over the deliberate 15-year lifetime, however one for every of the a number of floor missions involving Gateway proposed within the Artemis structure. The outside of Gateway and Visiting Autos which dock to it are coated in crucial techniques akin to solar arrays, radiators, docking mechanisms and seals, fluid switch connectors, communication antennae, exterior robotic techniques, and scientific payloads.”

Fortunately, plenty of analysis has been carried out because the Apollo missions to characterize the bodily properties of lunar regolith. Primarily based on this, scientists have deduced that the hazard posed by lunar regolith is dynamic and dependent upon spacecraft configuration, perspective (with respect to the sun), and the plasma setting. In a earlier research, Lee and co-author Gary L. Brown (Barrios Expertise) developed a brand new mannequin for characterizing the menace it posed to the Lunar Gateway, which they named the Gateway On-orbit Lunar Mud Modeling and Evaluation Program (GOLDMAP).

Utilizing this mannequin, Lee, Brown, and their crew thought-about the Artemis mission structure and modeled totally different points of it. This included the pure setting and spacecraft charging utilizing NASA’s Design Specification for Pure Environments (DSNE), the open-source Spacecraft Plasma Interplay Software program (SPIS), and knowledge from the Steward Observatory Mirror Laboratory (SOML). This was mixed with a time-dependent particle transport mannequin, which used Siemens STAR-CCM software program to characterize the fluid dynamics.

From this, they got here to varied conclusions concerning the Gateway and attainable contamination by astronauts coming and going utilizing the Human Touchdown System (HLS). Because the researchers wrote, “Throughout lunar floor missions, the HLS automobile parts will doubtless be subjected to contamination by small lunar regolith particles on the lunar floor due each to pure phenomena, akin to electrostatic lofting and levitation inside just a few meters above the lunar floor, and micrometeoroid impacts, which have been proven by each experiment and modeling to contribute to each the near-surface and excessive altitude dust populations, and human floor actions together with PSI of the thrusters throughout descent and ascent.”

Primarily based on this, it’s clear that the Lunar Gateway—the nexus level for future lunar exploration and improvement—shall be weak to dust switch. As such, the necessity for decontamination measures for astronauts coming back from the lunar floor can be made clear. Trying ahead, Lee and his colleagues emphasize that mannequin validation is critical utilizing laboratory experiments carried out by NASA consultants and teachers. In addition they advocate future on-orbit dust detection and dust-collecting payloads on the outside of the Gateway.

The outcomes of those experiments will assist inform NASA’s mission planners and operations aboard the Gateway because the Artemis Program unfolds. It should additionally doubtless inform future tips and “finest practices” for working on the lunar floor.