Using data collected by India’s Chandrayan mission, NASA has detected magmatic water locked under the surface of the Moon. The findings represent the first remote detection of this form of water that originates from deep within the Moon’s interior, NASA researchers said. Earlier studies had shown the existence of magmatic water in lunar samples returned during the Apollo programme.
NASA said scientists using data from the Moon Mineralogy Mapper (M3) instrument aboard the Indian Space Research Organisation’s Chandrayaan-1 spacecraft, remotely detected magmatic water, or water that originates from deep within the Moon’s interior, on the lunar surface.
M3 imaged the lunar impact crater Bullialdus, which lies near the lunar equator. “This rock, which normally resides deep beneath the surface, was excavated from the lunar depths by the impact that formed Bullialdus crater,” said Rachel Klima, a planetary geologist at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel.
“Compared to its surroundings, we found that the central portion of this crater contains a significant amount of hydroxyl – a molecule consisting of one oxygen atom and one hydrogen atom – which is evidence that the rocks in this crater contain water that originated beneath the lunar surface,” Klima said.
In 2009, M3 provided the first mineralogical map of the lunar surface and discovered water molecules in the polar regions of the Moon.
“This internal magmatic water also provides clues about the moon’s volcanic processes and internal composition, which helps us address questions about how the moon formed, and how magmatic processes changed as it cooled,” Klima added.
The Moon Mineralogy Mapper, or M3, imaged a 37-mile-wide (60 kilometers) impact crater near the lunar equator called Bullialdus, whose central peak is composed of a type of rock that forms when magma is trapped deep underground. This rock was excavated and exposed by the impact that formed Bullialdus
The solar wind — the stream of charged particles flowing from the sun — can create thin layers of water molecules when it strikes the lunar surface. Indeed, M3 found such water near the poles when it mapped the moon’s surface in 2009.
But scientists think the solar wind can only form significant quantities of surface water at high latitudes, ruling out this process as the source of the stuff in the more equatorial Bullialdus Crater.
The new findings, which are detailed in the Aug. 25 edition of the journal Nature Geoscience, further fuel scientists’ growing realization that the moon is not the bone-dry place it was long assumed to be.
There are those 2009 observations by the M3 instrument, for example. Also in 2009, NASA’s Lunar Crater Observation and Sensing Satellite missions mashed an impactor into the moon’s permanently shadowed Cabeus Crater, throwing up a huge plume of water vapor and ice particles.
Scientists now think many polar craters on the moon harbor large amounts of water ice — so much, in fact, that firms such as the Shackleton Energy Company and Moon Express aim to mine this ice and turn it into rocket propellant to help fuel humanity’s expansion out into the solar system.
Chandrayaan-1 was India’s first robotic moon probe. The spacecraft launched in October 2008 and sent an impactor into the lunar surface a month later, making India the fourth nation to plant its flag on the moon. Chandrayaan-1 continued making science observations from lunar orbit until August 2009, when it abruptly stopped communicating with Earth.
This water is thought to be a thin layer formed from solar wind hitting the Moon’s surface. Bullialdus crater is in a region with an unfavourable environment for solar wind to produce significant amounts of water on the surface, NASA said.
“This impressive research confirms earlier lab analyses of Apollo samples, and will help broaden our understanding of how this water originated and where it might exist in the lunar mantle.”
– Yvonne Pendleton, NLSI Director