Monday, March 11, 2024

Race for the Moon's water: Why go so far for something Earth isn't short of?

Sky News on Youtube has the story.

As a pioneering mission prepares for lift-off this week, the eyes of the world once more turn upwards - to the moon.

A rocket carrying NASA technology will blast off for the unexplored lunar south pole - part of an Earth-wide drive to find a crucial substance: water.

Hopefully, a greater amount of water can be found somewhere.

In 2020, data from NASA's SOFIA mission confirmed water exists in the sunlit area of the lunar surface as molecules of H2O embedded within, or perhaps sticking to the surface of, grains of lunar dust.

Observations from instruments on orbiters and probes found that the Moon's north and south poles probably contain over 1.3 trillion pounds (600 billion kilograms) of water ice.

Scientists have discovered a new and renewable source of water on the moon for future explorers in lunar samples from a Chinese mission. Water was embedded in tiny glass beads in the lunar dirt where meteorite impacts occur.

The first evidence of water in moon atmosphere came by an Indian device Chandra's Altitudinal Composition (CHACE) that was mounted on Moon Impact probe released from Chandrayaan -1.

So-called "Lunar Water" is water that is present on the Moon. Diffuse water molecules in low concentrations can persist at the Moon's sunlit surface, as discovered by the SOFIA observatory (an 80/20 joint project of NASA and the German Aerospace Centre, DLR) in 2020. Gradually, water vapor is decomposed by sunlight, leaving hydrogen and oxygen lost to outer space. Scientists have found water ice in the cold, permanently shadowed craters at the Moon's poles. Water molecules are also present in the extremely thin lunar atmosphere.

NASA's Ice-Mining Experiment-1 (set to launch on the PRIME-1 mission no earlier than late 2024) is intended to answer whether or not water ice is present in usable quantities in the southern polar region.

Water (H2O) and the related hydroxyl group (-OH) exist in forms chemically bonded as hydrates and hydroxides to lunar minerals (rather than free water), and evidence strongly suggests that this is the case in low concentrations as for much of the Moon's surface.

Inconclusive evidence of "free water ice" at the lunar poles had accumulated during the second half of the 20th century from a variety of observations suggesting the presence of bound hydrogen.

On 18 August 1976, the Soviet Luna 24 probe landed at Mare Crisium, took samples from the depths of 118, 143, and 184 cm of the lunar regolith, and returned them to Earth. In February 1978, laboratory analysis of these samples showed that they contained 0.1% (1,000 ppm) water by mass. Spectral measurements certainly showed minima near 3, 5, and 6 µm, distinctive valence-vibration bands for water molecules, with intensities two or three times larger than the noise level.

On 24 September 2009, the Indian Space Research Organisation's Chandra's Altitudinal Composition Explorer (CHACE) and NASA's Moon Mineralogy Mapper (M3) spectrometer on board the Chandrayaan-1 probe had detected absorption features near 2.8–3.0 μm on the surface of the Moon. On 14 November 2008, Chandrayaan-1 released the Moon Impact Probe to impact the Shackleton crater, which helped confirm the presence of water ice. For silicate bodies, such features are typically attributed to hydroxyl- and/or water-bearing materials. In August 2018, NASA confirmed that M3 showed water ice is present on the surface at the Moon poles. Water in concentrations of 100 to 412 parts per million (0.01%-.042%) was confirmed to be on the sunlit surface of the Moon by the SOFIA observatory on October 26, 2020.

Water may have been delivered to the Moon over geological timescales by the regular bombardment of water-bearing comets, asteroids, and meteoroids or continuously produced in situ by the hydrogen ions (protons) of the solar wind impacting oxygen-bearing minerals.

The search for a greater presence of lunar water continues. Water would be very useful for long-term lunar habitation.

No comments:

Post a Comment