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Bottoms of lunar polar craters may harbor ice patches

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Water will be a vital resource for astronauts on the moon

By Will Dunham

Feb 26 (Reuters) - A dishwasher-sized NASA satellite was

launched into space from Florida on Wednesday to identify where

water - a precious resource for lunar missions - resides on the

moon's surface in places such as the permanently shadowed

craters at its poles.

A SpaceX Falcon 9 rocket lifted off from the Kennedy Space

Center in Cape Canaveral carrying NASA's Lunar Trailblazer

orbiter. The Lunar Trailblazer spacecraft was built by Lockheed

Martin's ( LMT ) space division. The satellite was a secondary

payload onboard the rocket, with the primary payload being a

lunar lander mission led by Intuitive Machines ( LUNR ).

The lunar surface is often thought of as arid but previous

measurements have found the presence of some water, even in

warmer sun-lit locations. In cold and permanently shadowed

places at the lunar poles, it has long been hypothesized that

there could be significant amounts of water ice.

Lunar Trailblazer, which weighs about 440 pounds (200 kg)

and measures about 11.5 feet (3.5 meters) wide when its solar

panels are fully deployed, is being sent to find and map this

water on the moon's surface.

For future moon exploration, including potential long-term

lunar bases staffed by astronauts, lunar water would be of vital

importance because it could be processed not only as a drinking

supply but also into breathable oxygen and hydrogen fuel for

rockets.

The bottoms of hundreds of craters at the moon's South Pole,

for instance, are permanently shadowed and may hold ice patches.

Some water also may be locked inside broken rock and dust on the

lunar surface.

Lunar Trailblazer is scheduled to perform a series of moon

flybys and looping orbits over a span of several months to

position itself to map the surface in detail. It eventually will

orbit at an altitude of roughly 60 miles (100 km) and collect

high-resolution images of targeted areas to determine the form,

distribution and abundance of water and to better understand the

lunar water cycle.

"We see tiny amounts of water on sunlit portions of the

moon, which is mysterious," said planetary scientist Bethany

Ehlmann, the mission's principal investigator and director of

Caltech's Keck Institute for Space Studies.

But, Ehlmann added: "The most interesting (aspect) for many

is the potentially large amounts of ice in the permanently

shadowed regions of the lunar poles. Lunar Trailblazer will peer

inside to see how much is at the surface."

Such locations could serve as a resource for lunar explorers

in the future.

"Understanding where a rover would drive or an astronaut

would walk to examine deposits for science and future resource

use will benefit all future landed missions," Ehlmann said.

Two Lunar Trailblazer instruments will take measurements

from orbit together. The Lunar Thermal Mapper, or LTM, will map

and measure the lunar surface temperature. The High-resolution

Volatiles and Minerals Moon Mapper, or HVM3, will look at the

moon's surface for a telltale pattern of light given off by

water.

"We believe that the movement of water on the moon is likely

driven by the surface temperature. So by measuring the presence

and amount of water via the HVM3 instrument and the surface

temperature via the LTM instrument we can better understand this

relationship," said University of Oxford planetary scientist

Tristram Warren, who worked on developing the LTM instrument.

Lunar water is thought to come from several potential

sources. One possibility is that solar wind - charged particles

from the sun - could react with lunar minerals to create water.

Another source might be comets or meteorites, which may have

delivered water to the moon over billions of years. The exact

amount of lunar water remains uncertain, but it is potentially

hundreds of millions of tons.

"Other than for human exploration, lunar water is also

scientifically very exciting. The moon has been orbiting near

the Earth almost since the formation of Earth itself. So

understanding the origin of the lunar water might help us to

understand the origin of water on Earth," Warren said.