Water is a critical resource for long-term exploration, and that’s one of the main reasons NASA will send astronauts to the Moon’s South Pole by 2024. Water is a necessity for furthering human exploration because it could potentially be used for drinking, cooling equipment, breathing and making rocket fuel for missions farther into the solar system.
The South Pole region contains ice and may be rich in other resources based on our observations from orbit, but, otherwise, it’s a completely unexplored world. The South Pole is also a good target for a future human landing because robotically, it’s the most thoroughly investigated region on the Moon. The elliptical, polar orbit of NASA’s Lunar Reconnaissance Orbiter (LRO) is closest to the Moon during its pass over the South Pole region. Through its thousands of orbits in the last decade, LRO has collected the most precise information about the South Pole region than any other, offering scientists precise details about its topography, temperature and locations of likely frozen water.
Water on the Moon
The floors of polar craters reach frigid temperatures because they’re permanently in shadow as a result of the low angle at which sunlight strikes the Moon’s surface in the polar regions. This angle is based on the 1.54-degree tilt of the Moon’s axis (Earth’s is 23.5 degrees). If an astronaut was standing near the South Pole, the Sun would always appear on the horizon, illuminating the surface sideways, and, thus, skimming primarily the rims of deep craters, and leaving their deep interiors in shadow.
These permanently shadowed craters feature some of the lowest temperatures in the solar system — down to -414 degrees Fahrenheit (-248 Celsius). Water ice is stable at these temperatures and it is believed that some of these craters harbor significant ice deposits.
The South Pole’s frozen water may date back billions of years and has been untainted by the Sun’s radiation or the geological processes that otherwise constantly churn and renew planetary surfaces (think of wind and erosion on Earth), offering us a window into the early solar system.
Constant Light and Power
Other extremes at the Moon’s South Pole are not so dark and cold — there are also areas, near Shackleton crater for instance, that are bathed in sunlight for extended periods of time, over 200 Earth days of constant illumination. This happens also because of the Moon’s tilt and is a phenomenon that we experience at our own polar regions on Earth. Unrelenting sunlight is a boon to Moon missions, allowing explorers to harvest sunlight in order to light up a lunar base and power its equipment.
The president’s direction from Space Policy Directive-1 galvanizes NASA and commercialized space companies to return to the Moon and builds on progress on the Space Launch System rocket and Orion spacecraft, collaborations with U.S industry and international partners, and knowledge gained from current robotic assets at the Moon and Mars.