Scientists have detected more than 40 ice-filled craters in the moon's North Pole using data from a NASA radar that flew aboard India's Chandrayaan-I. NASA's Mini-SAR instrument, lightweight, synthetic aperture radar, found more than 40 small craters with water ice. The craters range in size from 2 to 15 km in diameter. The finding would give future missions a new target to further explore and exploit, a NASA statement said, adding it is estimated that there could be at least 600 million metric tons of water ice in the craters. "The emerging picture from the multiple measurements and resulting data of the instruments on lunar missions indicates that water creation, migration, deposition and retention are occurring on the moon," Paul Spudis, principal investigator of the Mini-SAR experiment at the Lunar and Planetary Institute, said yesterday.
In November, NASA crashed a probe into the Cabeus crater near the moon’s south pole and also found evidence of water. Scientists recently solved some longstanding lunar mysteries, including how the Moon is producing its own water. While it turns out that the Moon is not made out of Swiss cheese (disappointing, I know—that would have been a food source for lunar explorers), it does act like a big sponge of sorts. The lunar surface is a loose collection of irregular dust grains, known as regolith. Basically, the regolith absorbs electrically charged particles given out by the Sun. These electrically charged particles interact with molecules of oxygen that are already present in lunar dust, and voila, you have H2O.
Incoming protons are trapped in the spaces between the grains, absorbed, and then interact with the oxygen in the lunar regolith to produce hydroxyl and water.
So, there’s water on the moon, and we now know how it’s getting there, but what does that do for us from a practical standpoint? Could humans living on a lunar base drink this moon water, for example?
“The main problem on making water available for human consumption will be how to extract it from the lunar rocks,” Detlef Koschny, an ESA Chandrayaan-1 Project Scientist, explained to The Daily Galaxy. “This is technically very challenging and needs to be solved first.”
This discovery, made by SARA (an instrument jointly built by scientific groups from Sweden, India, Japan, and Switzerland an attached to the Chandrayaan-1 lunar orbiter that recently finished its mission in August 2009) should help pave the way for understanding if, and how, a lunar base could rely on moon water for its human inhabitants.
Chandrayaan-1 SARA measurements of hydrogen flux recorded on the Moon on 6 February 2009.
According to Koschny, we’ve still got a long ways to go before this water can be harvested, but understanding how the water is produced on the moon in the first place is an important first step in figuring out how to collect it.
As a fringe benefit, the SARA results will also potentially help scientists get better images of objects in our solar system. The research confirmed that solar hydrogen nuclei are indeed being absorbed by the lunar regolith but also revealed a mysterious occurrence: not every proton is absorbed. One out of every five rebounds into space. In the process, the proton joins with an electron to become an atom of hydrogen.
“We didn’t expect to see this at all,” says Stas Barabash, Swedish Institute of Space Physics.
This artist's concept shows the Indian lunar orbiter Chandrayaan-1. The spacecraft will carry two European experiments on board which are direct descendents of ESA's SMART-1 - the infrared spectrometer, SIR2, and the X-ray spectrometer, C1XS, to study the mineralogy and the chemical composition of the lunar surface. The third European instrument on board is the SARA Sub-kiloelectronvolt Atom Reflecting Analyser, that will study the interaction between the lunar surface and the solar wind.
“Current imaging techniques use the reflection of light from the surface. It is possible to determine surface composition by taking images at different wavelengths - but this only allows to constrain the mineral composition (minerals are composed of different elements) of the material,” Koschny explained to The Daily Galaxy.
The Sub Kev Atom reflecting Analyser (SARA)on board the lunar mission Chandrayaan-1. SARA is the first-ever lunar experiment dedicated to direct studies of plasma-surface interactions in space.
But now it’s going to be a whole new ball game, because instead of making inferences we’ll be looking at the real deal.
Using an instrument like SARA allows to produce a map of the elements itself, so it's a more direct technique to determine the surface composition.