Human beings carry millions of microbes with us; in fact, we need them—especially in our stomachs—to survive and digest food. It is estimated that there are over a million bacteria on any given patch of skin—a huge number—so it is inevitable that some bacteria and fungi will eventually escape from spacesuits and habitats. This presents a challenge, not only due to the risk of microbial contamination spreading to areas on the Moon containing water ice, but also because they could spread throughout any future lunar colonies.

Imagine the not-too-distant future: bases have been established on the Moon or within lunar caverns—ideal locations for construction. You could build entire cities and factories there; some lunar caverns span kilometers and offer immense capacity. In fact, it is believed that at greater depths—500 meters or even over a kilometer down—there may be caverns formed by volcanic activity more than a billion years ago. These caverns could measure two or three kilometers in diameter—not just length, but diameter—making them truly massive. You could seal these caverns, fill them with air, and regulate the temperature to create a perfect habitat for walking around, building a city, setting up a factory, or doing whatever else you might wish.

However, all those microorganisms could proliferate explosively; while they face limitations—such as predators—here on Earth, they might encounter no such threats on the Moon. Low-gravity conditions could trigger a biological explosion of these fungi and bacteria; a colony established in one of the Moon's vast volcanic tunnels would, within 20 or 30 years, inevitably face a massive, pervasive presence of fungi or bacteria—some of which might even mutate.

That is why these studies are so crucial: they identify the hardiest microorganisms and help us devise strategies to combat, control, and contain them in the future.

These studies are important because they show us which microorganisms can survive in the conditions of lunar ice—specifically in areas of the Moon shielded from sunlight, where microorganisms and fungi can persist in a dormant state. If these same microorganisms were to enter a base or a cave that we had adapted to house our factories or cities, they could undergo a biological population explosion; lacking predators or natural constraints—and potentially even reacting to low gravity—they could become biologically active in an uncontrolled manner.

Therefore, these studies are crucial for identifying the hardiest microorganisms and for devising strategies to combat or control them.