Magnetic refuge found on Moon

A mini magnetic field has been detected on the surface of the moon

A miniature magnetic field has been imaged on the surface of the moon, making it a rare, minimally protective lunar refuge from some aspects of the harsh solar wind.

The magnetic region could be a great place to site a lunar base, since tomorrow's lunar colonists will not only need water , but some protection from the heavy radiation in the solar wind.

"You can think of it as kind of a mini umbrella," said Martin Wieser of the Swedish Institute of Space Physics in Kiruna, Sweden. "It will be effective for certain kinds of (space) weather.

But it is very weak in comparison to Earth's planet-wide magnetic field or even compared to the splotchy magnetospheres of Mars.

The 224-mile- (360-kilometer-) wide magnetosphere was detected by an instrument on the Indian Chandrayaan-1 spacecraft. The mini magnetosphere revealed itself by fewer hydrogen atoms scattering off the surface of the moon. Generally when the solar wind rams into the airless surface of the moon, some hydrogen atoms scatter back into space. Any place with fewer of these atoms rising up from the moon is likely to be shielded magnetically, explained Wieser and his colleagues in their paper published in Geophysical Research Letters.

The researchers also noticed that the dust inside the magnetically shielded zone is brighter than the surrounding areas, which might have something to do with the solar wind weathering that surface differently over the eons.

"I think this is a very exciting observation," said lunar researcher Jasper Halekas of the Space Science Laboratory at the University of California at Berkeley. "There have been a number of indications that theses things were taking place. (But) this is the first directed study that really tells you 'they are there.'"

The lunar magnetospheres are a lot like those on Mars, said Halekas, except that on Mars they are almost certainly the remnants of a global magnetic field that was created by the planet's core. A molten core dynamo on the moon is a bit less likely, however.

"It's still quite possible that there was a dynamo on the moon," said Halekas.

Another possibility is that the mini-magnetosphere was generated by large impacts on the direct opposite side of the moon. Exactly how this works is far from clear, but there does seem to be a correlation between large impact craters and magnetic anomalies at their antipodes, said Wieser. 

Ironically, the same magnetic shielding could make these the driest places on the moon. One mechanism believed to generate at least the ingredients for water on the moon are solar protons smacking into the surface, forming hydrogen atoms in the lunar soils. Inside a mini magnetosphere that is less likely to happen, Wieser noted.

Without water, maybe this isn't the best lunar real estate after all.

 

Tons of water ice found on moon's north pole

Discovery opens up another region of potential exploration, says NASA

 Vast pockets of water ice numbering in the millions of tons have been discovered at the north pole of the moon, opening up another region of the lunar surface for potential exploration by astronauts and unmanned probes, NASA announced Monday.

A NASA radar instrument on an Indian moon probe found evidence of at least 600 million metric tons of water ice spread out on the bottom of craters at the lunar north pole. It is yet another supply of lunar water ice, a vital resource that could be mined to produce oxygen or rocket fuel to support a future moon base, NASA officials said.

More than 40 craters ranging from 1 mile (2 km) to 9 miles (15 km) wide were found harboring the water ice, which was detected using NASA's Mini-SAR radar instrument on India's Chandrayaan-1 lunar orbiter. The instrument is also known as Mini-RF in NASA parlance.

"After analyzing the data, our science team determined a strong indication of water ice, a finding which will give future missions a new target to further explore and exploit," said Jason Crusan, program executive for the Mini-RF Program for NASA's space operations program in Washington, D.C., in a statement.

Water, water everywhereThe ice was discovered in permanently shadowed craters at the moon's north pole. Similar conditions of perpetual night exist at the moon's south pole as well, where water ice was also confirmed to be present last year. Because these regions never see sunlight, water can stay in its frozen form indefinitely.

Last September, NASA and other scientists confirmed without a doubt the existence of water ice at the moon's south pole, as well as signals of water molecules across large areas of the lunar surface. Several spacecraft, including India's Chandrayaan-1 probe that carried the radar instrument used for the new findings, found hard evidence of water on the moon.

In October, NASA crashed two impactor probes into the lunar south pole in an attempt to kick up clouds of water ice and measure it from an orbiting spacecraft and other space and ground-based observatories. The subsequent analysis turned up significant amounts of water and water vapor in the debris cloud, NASA scientists said.

"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," said Paul Spudis, principal investigator of the Mini-SAR experiment at the Lunar and Planetary Institute in Houston, in a statement. "The new discoveries show the moon is an even more interesting and attractive scientific, exploration and operational destination than people had previously thought."

The research will be detailed in the journal Geophysical Research Letters.

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Will astronauts go?Water ice is a tantalizing find anywhere on the moon because it can serve as a natural resource for astronauts on future lunar landing missions. The ice could be melted into drinking water or be separated into its component oxygen and hydrogen to provide breathing air and rocket fuel, NASA officials have said in the past.

NASA had planned to send astronauts on new lunar landing missions by 2020 as part of its Constellation program. The program was building the new Altair moon landers, as well as the Orion spacecraft and Ares rockets needed to launch ferry them to lunar surface, but experts said it was extremely underfunded and behind schedule.

Last month, President Barack Obama ordered NASA to cancel the Constellation program and focus on using commercial spacecraft to launch American astronauts to orbit instead. The move is aimed at freeing up NASA to concentrate on more lofty exploration missions, such as returning to the moon or sending astronauts to visit an asteroid, stable regions in space called Lagrange points or the moons of Mars.

NASA chief Charles Bolden told members of the U.S. Senate and Congress last week that Mars is expected to be the ultimate destination for astronauts. But the moon, he said, is still a good interim target to serve as a stepping stone for more distant space exploration goals.

Chandrayaan-1's Mini-SAR radar was one of two instruments involving NASA on India's Chandrayan-1 spacecraft. The probe also carried the Moon Mineralogy Mapper for NASA. A version of Mini-SAR, called Mini-RF, is riding on NASA's Lunar Reconnaissance Orbiter.

India launched Chandrayaan-1 probe in October 2008 and carried 11 instruments to observe the moon from lunar orbit. It was India's first moon probe and carried an impactor probe that it unleashed in November 2008. The spacecraft went offline in late August 2009 after an abrupt malfunction cut off communications with Earth.