September 25, 2009

NASA and Science Journal Information about Water on the Moon

These images show a very young lunar crater on the side of the moon that faces away from Earth, as viewed by NASA's Moon Mineralogy Mapper on the Indian Space Research Organization's Chandrayaan-1 spacecraft. On the left is an image showing brightness at shorter infrared wavelengths. On the right, the distribution of water-rich minerals (light blue) is shown around a small crater. Both water- and hydroxyl-rich materials were found to be associated with material ejected from the crater.
Credits: ISRO/NASA/JPL-Caltech/USGS/Brown Univ.

NASA scientists have discovered water molecules in the polar regions of the moon. Instruments aboard three separate spacecraft revealed water molecules in amounts that are greater than predicted, but still relatively small. Hydroxyl, a molecule consisting of one oxygen atom and one hydrogen atom, also was found in the lunar soil. The findings were published in Thursday's edition of the journal Science.

This site had a previous article based on the leaked information on moon water and the latest work on fuel depots in space. The water should be used to supply fuel depots to lower the cost of working and living in space.

The journal Science has an article "A Whiff of Water Found on the Moon"

Three independent groups today announced the detection of water on the lunar surface, their find is at most a part per 1000 water in the outermost millimeter or two of still very dry lunar rock.

The discovery has potential, though. Future astronauts might conceivably wring enough water from not-completely-desiccated lunar "soil" to drink or even to fuel their rockets. Equally enticing, the water seems to be on its way to the poles, where it could be pumping up subsurface ice deposits that would be a real water bonanza.

The Moon Mineralogy Mapper (M3) that has been orbiting the moon onboard India's now-defunct Chandrayaan-1 spacecraft. A spectrometer, M3 detected an infrared absorption at a wavelength of 3.0 micrometers that only water or hydroxyl--a hydrogen and an oxygen bound together--could have created.

But spectroscopists had long distrusted any sign of water in lunar data because Apollo moon rocks were so bone-dry. So M3 team members asked the researchers operating the spectrometer on NASA's EPOXI spacecraft to take a look as it passed the moon last June on its way to comet Hartley 2. EPOXI observations confirmed the M3 detection, as did a reanalysis of Cassini spectrometer data taken in 1999 on its way to Saturn. The three analyses are reported in separate papers in Science.

The best estimate coming out of the reported observations for water's abundance is 0.2 to 1 part per 1000 of water, she says, and that's in the upper millimeter or two that spectroscopy can penetrate. At those levels, an astronaut would have to process the soil from a baseball-diamond-size plot to get a decent drink of water.

More tantalizing, the water becomes more abundant closer to the poles. That and water's abundance varying with time suggests to Pieters that water is being produced on the moon--perhaps through solar wind hydrogen interacting with surface rock--and then hopscotching from place to place through the moon's vanishingly thin atmosphere. Because a water molecule would stick more securely to colder rock, water would tend to migrate toward the colder polar regions. There, it might become trapped for eons as subsurface ice in permanently shadowed craters, which are currently thought to be among the coldest places in the solar system.

Character and Spatial Distribution of OH/H2O on the Surface of the Moon Seen by M3 on Chandrayaan-1

The search for water on the surface of the anhydrous Moon remained an unfulfilled quest for 40 years. The Moon Mineralogy Mapper (M3) on Chandrayaan-1 has now detected absorption features near 2.8-3.0 µm on the surface of the Moon. For silicate bodies, such features are typically attributed to OH- and/or H2O-bearing materials. On the Moon, the feature is seen as a widely distributed absorption that appears strongest at cooler high latitudes and at several fresh feldspathic craters. The general lack of correlation of this feature in sunlit M3 data with neutron spectrometer H abundance data suggests that the formation and retention of OH and H2O is an ongoing surficial process. OH/H2O production processes may feed polar cold traps and make the lunar regolith a candidate source of volatiles for human exploration

9 page pdf with supplemental information for Character and Spatial Distribution of OH/H2O on the Surface of the Moon

Detection of Adsorbed Water and Hydroxyl on the Moon by
Roger N. Clark

Data from the Visual and Infrared Mapping Spectrometer (VIMS) on Cassini during its fly-by of the Moon in 1999 show a broad absorption at 3µm due to adsorbed water and near 2.8µm attributed to hydroxyl in the sunlit surface on the Moon. The amounts of water indicated in the spectra depend on the type of mixing, and the grain sizes in the rocks and soils but could be 10 to 1,000 parts per million and locally higher. Water in the polar regions may be water that has migrated to the colder environments there. Trace hydroxyl is observed in the anorthositic highlands at lower latitudes

10 page pdf with supplemental information about Detection of Adsorbed Water and Hydroxyl on the Moon

Temporal and Spatial Variability of Lunar Hydration as Observed by the Deep Impact Spacecraft

The Moon is generally anhydrous, yet the Deep Impact spacecraft found the entire surface to be hydrated during some portions of the day. OH and H2O absorptions in the near infrared were strongest near the North Pole and are consistent with <0.5 wt% H2O. Hydration varied with temperature, rather than cumulative solar radiation, but no inherent absorptivity differences with composition were observed. However, comparisons between data collected one week (a quarter lunar day) apart show a dynamic process with diurnal changes in hydration that were greater for mare basalts (~70%) than for highlands (~50%). This hydration loss and return to steady state occurred entirely between local morning and evening, requiring a ready daytime source of water group ions, which is consistent with a solar wind origin.

3 page pdf with supplemental information on Temporal and Spatial Variability of Lunar Hydration as Observed by the Deep Impact Spacecraft

The Deep Impact HRI‐IR spectrometer was used to look at the moon three times and saw signs of water as well.

A Lunar Waterworld by Paul G. Lucey Science DOI: 10.1126/science.1181471
Space-based spectroscopic measurements provide strong evidence for water on the surface of the Moon

How to Find Water on the Moon

These graphs show detailed measurements of light as a function of color or wavelength. The data, called spectra, are used to identify minerals and molecules. On the left are spectra of lunar rocks, minerals and soil returned to Earth by NASA's Apollo missions, taken in the visible to shorter-wavelength infrared range. The blue bar shows where a dip in the light is expected due to the presence of water and hydroxyl molecules. To the right are model spectra for pure water (H2O) and hydroxyl (OH-).

Image credit: ISRO/NASA/JPL-Caltech/Brown Univ.

Dispersing Light through the Moon Mineralogy Mapper

The Moon Mineralogy Mapper is a state-of-the-art NASA imaging spectrometer. Sunlight reflected off the moon enters the telescope and then is passed by mirrors to the spectrometer. In the spectrometer, white light is dispersed into different wavelengths (from 0.43 to 3 micrometers) for every point in an image. Once in orbit around the moon, the instrument generates three-dimensional cubes of data that allow scientists to map the composition of the surface.
Image credit: NASA/JPL-Caltech

Water Detected at High Latitudes

This image of the moon is from NASA's Moon Mineralogy Mapper on the Indian Space Research Organization's Chandrayaan-1 mission. It is a three-color composite of reflected near-infrared radiation from the sun, and illustrates the extent to which different materials are mapped across the side of the moon that faces Earth.

Small amounts of water and hydroxyl (blue) were detected on the surface of the moon at various locations. This image illustrates their distribution at high latitudes toward the poles.

Blue shows the signature of water and hydroxyl molecules as seen by a highly diagnostic absorption of infrared light with a wavelength of three micrometers. Green shows the brightness of the surface as measured by reflected infrared radiation from the sun with a wavelength of 2.4 micrometers, and red shows an iron-bearing mineral called pyroxene, detected by absorption of 2.0-micrometer infrared light.
Image credit: ISRO/NASA/JPL-Caltech/Brown Univ./USGS

Daytime Water Cycle on the Moon

This schematic shows the daytime cycle of hydration, loss and rehydration on the lunar surface. In the morning, when the moon is cold, it contains water and hydroxyl molecules. One theory holds that the water and hydroxyl are, in part, formed from hydrogen ions in the solar wind. By local noon, when the moon is at its warmest, some water and hydroxyl are lost. By evening, the surface cools again, returning to a state equal to that seen in the morning. Thus, regardless of location or terrain type, the entire surface of the moon is hydrated during some part of the lunar day.
Credit: University of Maryland/McREL

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