The LSIC Extreme Environment (LSIC-EE) subgroups regularly convene interested members of the community to discuss and develop recommendations in support of the greater focus group. An additional important output of the subgroups are wiki-style "user guides" for relevant environment conditions aimed at observations, simulation, and/or testing for an introductory audience (students / post-docs / industry new to space qualification) and FAQs addressing issues and pitfalls for all levels of experience.

The environmental conditions covered by each subgroup are described below.

Radiation Environment Subgroup (Lead: Lawrence Heilbronn)

This subgroup considers ionizing radiation that can cause harmful biological and electronic effects. The ionizing radiation environment is made up of three sources - (1) Galactic Cosmic Rays (GCR), a continuous flux of high energy particles made up of electrons, protons, and heavier ions made up of nuclei of all naturally occurring elements; (2) Solar Energetic Particles (SEP) consisting primarily of protons with some heavier nuclei that are emitted sporadically from the sun in events such as coronal mass ejections; and (3) albedo secondary radiation that is produced by GCR and SEP interaction in lunar soil, creating a flux of charged light ions and neutrons. Recent calculations and measurements show that the dose from GCR to crew members during relatively short stays on the Moon will be below current limits for health effects; however, a large SEP event could have immediate detrimental effects on both crew and electronics if not properly shielded. Real-time monitoring of the radiation environment and crew doses is required to maintain the safety and health during operations on the Moon. Space weather (see "Space Weather / Plasma Environment" subgroup) also affects the intensity of GCR and the probability of a SEP event. Fission power sources on the Moon will create a man-made radiation field that will consist of low-energy neutrons (below 20 MeV) and gamma rays. If utilized, these power sources will add to the overall radiation encountered on the Moon and will require shielding that is consistent with their operation.

Regolith / Surface Interface Subgroup (Lead: Melissa Roth)

Regolith is the layer of unconsolidated, breccia, rock fragments and dusty debris that varies in thickness from roughly 5 meters on Mare surfaces to 10 meters on Highland surfaces. Surface interface is the contact or relationship between lunar surface technologies and the regolith. This subgroup will focus on the properties of lunar regolith and its effect on our ability to survive and operate on the lunar surface, specifically how interfacing with the surface presents risks and challenges to technological development. This subgroup will also explore SKGs, needed technology, and potential solutions.

Space Weather / Plasma Environment Subgroup (Lead: Michael Zimmerman)

This subgroup focuses on ambient and human-induced plasma environments which influence electric potentials and the risk of electrostatic discharging on the lunar surface, humans, and engineering interfacing therewith. Ambient environments require descriptions of the nominal, climatological, mean as well as extreme, transient, or severe cases – all with quantified uncertainties. The plasma environment at the lunar surface is solar wind driven with variability caused by the moon’s position relative to the earth’s magnetotail, Solar Particle Events (SPE), Galactic Cosmic Rays (GCR) and Coronal Mass Ejections (CMEs). The resultant effects, specifically potential differences between adjacent objects are also dependent upon surface features / properties such as Solar Zenith Angle (SZA), regolith properties, terrain, geology, latitude, magnetic fields, and more. The range of potentials may be as broad as +100 V to -1000 V with rapid fluctuations likely and excursions possible. Risks to sustained habitation range from "nuisance" – tribocharging (dust, contamination, …) or limited lifetimes of EEE parts to "catastrophic" – critical systems failures (solar arrays) or injury to humans. Efforts will focus on the (1) definition of relevant environments; (2) lunar sites of particular interest; (3) nowcasting, forecasting, and sensing, (4) modelling, and (5) ground based testing and laboratories – state of the art, gaps, and opportunities.

Thermal & Illumination Environment Subgroup (Lead: Ahsan Choudhuri)

The thermal environment is a critical design consideration for any engineered systems on the lunar surface. The lunar thermal environment imposes significant variability, such as 140K-400K temperature swing in the equator and 50K-202K in the polar region. Some of the critical technological challenges for the design development of surface operation systems due to this extreme thermal environment include performance degradation and fatigue due to thermal cycling, brittle phase transitions of metals, and electronics performance in an extremely cold environment. Lunar Illumination Environment is a key design driver for many surface operation hardware, including power and radiator systems. Illumination varies throughout the lunar day. The spatial variability of illumination is significant at poles, even over just a few kilometers. Obtaining power in the Permanently Shadowed Regions (PSRs) and thermal management in Persistently Illuminated Regions (PIRs) are some of the vital technology challenges imposed by the variability of the lunar illumination environment. The Thermal and Illumination Definition Subgroup activities aim to collect and catalog scientific literature to provide a comprehensive understanding of the lunar thermal and illumination environment.

Vacuum / Exosphere Environment Subgroup (Lead: Stephen Indyk)

The lunar atmosphere, or exosphere, is often characterized as a vacuum for most practical purposes. In actuality, surrounding the Moon is molecular flow of atoms and particles which include helium, neon, hydrogen, argon and other trace gases. Some are from outgassing from the Moon itself and others are contributed by the solar winds. Thermal conditions and the lunar day and night cycle noticeably affect the lunar exosphere as well.

External Hazards (Lead: Milena Graziano)