“There are indications of water ice at the Moon's south pole. But how did it get there? Apparently, very slowly. It accumulated at the poles over billions of years, rather than primarily through isolated major events like comet impacts. This is suggested by a study conducted by three scientists from the University of Colorado Boulder, recently published in *Nature Astronomy*.
In principle, there shouldn't be any water on the Moon. During the two-week-long lunar day, solar radiation causes temperatures to rise to 120 degrees Celsius—conditions that ought to drive all moisture out of the lunar soil in sunlit areas. Yet, this is not the case at the poles. The lunar south polar region, in particular, contains craters with floors that are never exposed to sunlight.
In fact, the first solid evidence of water ice in the lunar soil was discovered there in 2009 through observations made by Indian and American lunar missions. These deposits are ultimately due to the near-vertical orientation of the Moon's axis of rotation relative to the plane in which the Earth—with the Moon in tow—orbits the Sun. Consequently, in the Moon's polar regions, the Sun remains low on the horizon; where sufficiently high topographical features exist—such as crater walls—they cast perpetual shadows. The tilt of the lunar axis has steadily decreased since the Moon's formation approximately 4.5 billion years ago, causing these polar shadows to grow longer over time. The new study establishes a quantitative link between the age of the shadows and the water ice content: the longer a patch of lunar soil has been in shadow, the more ice it should contain.
That leaves the question of how the water arrived on the Moon in the first place. For one thing, it was present in the material from which the Moon originally formed. This water subsequently reached the surface through volcanism during the early stages of lunar history. Another possibility involves hydrogen atoms, whose nuclei originate from the solar wind constantly bombarding the Moon. As the hydrogen reacts with the oxygen in the lunar surface rocks, it also forms water molecules. However, comets and asteroids impacting the Moon also supply it with water. Once on the lunar surface, the molecules gradually migrate toward the poles, where they can accumulate as ice.
The study from Colorado sheds light on the history and current state of the Moon’s water inventory. This has become a matter of considerable importance, given that the USA and China are planning crewed missions and stations with the long-term goal of utilizing the Moon. Lunar ice would not only provide drinking water for astronauts but could also be used to produce breathable air and rocket fuel.” [1]
Since the mass of Moon is much smaller than the mass of Earth, it takes less energy to take this material into the travels through space from Moon.
Because the Moon has only 1.2% the mass and roughly 1/6 the surface gravity of Earth, its gravitational well is much shallower. This means you need significantly less energy and propellant to launch material from the lunar surface into space compared to launching it from Earth.
This difference in energy requirements is defined by the escape velocity required to break free from a celestial body's gravitational pull:
• Earth: Requires an escape velocity of approximately 11.2 km/s.
• Moon: Requires an escape velocity of only about 2.38 km/s.
Because of this dramatic difference, launching payloads, rockets, or resources from the Moon requires a fraction of the fuel needed to lift the exact same amount of mass off Earth. This makes the Moon a highly attractive staging ground and refueling station for deep-space missions.
1. Wie das Wasser auf den Mond kam: Eisvorkommen bauten sich über Jahrmilliarden auf. Frankfurter Allgemeine Zeitung; Frankfurt. 22 Apr 2026: N2. YANNICK DENGLER
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