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.

Charting unknown Himalayan waters

In the wake of a recent controversy over the retreat of Himalayan glaciers in which the UN's climate science body admitted that it was an error to assert that they would disappear by 2035, water availability has emerged as a key issue with even more uncertainty.

Receding Himalayan glaciers grabbed headlines because they feed major rivers in South Asia and some parts of Southeast Asia, which is home to a sizeable proportion of the planet's population.

If the glaciers significantly retreated or even disappeared, it would be an issue of life and death for many millions of people who depend on these rivers.

But now that the Intergovernmental Panel on Climate Change (IPCC) has said that it was a mistake to say the glaciers will be gone in a matter of decades, does that mean water is not a worrying issue any more?

Many scientists believe it is - even more so more given the uncertainty surrounding the future impacts of climate change in a region of not only high population, but one of high population growth.

The broad consensus is glaciers themselves are indeed retreating, although the rate of the recession may be debatable.

However, there are other climate-influenced factors that affect river flows, such as changes in precipitation, snowfall and regional temperature.

Uncertain times

"There has been too much focus on glaciers whereas there are other factors like precipitation and snowfall that affects the levels of waters in rivers downstream the eastern Himalayas," says Mats Eriksson, a senior hydrologist with Nepal-based International Centre for Integrated Mountain Development (ICIMOD), which has carried out several studies on the glaciers in the Hindu Kush Himalayas.

Without monsoon rains, young crops soon perish and die

Below the eastern part of the Himalayas are major rivers like the Ganges and the Bramhaputra, as well as their tributaries.

These are vital lifelines for millions of people in India, Bangladesh, Nepal, Bhutan and Tibet.

A recent study for the World Bank has shown that the volume of water resulting from glacial melt in Nepal makes up less than 5% of the flows of rivers leaving the country and contributing to the Ganges downstream.

"That is, about 95% or more of the river flow is the result of rain and melting seasonal snow," said report co-author Richard Armstrong, a glaciologist from the University of Colorado at Boulder in the US.

If that is true, rivers downstream of the eastern Himalayas will hardly be affected, even if the glaciers recede or disappear.

However, would the other contributing factors to the rivers' flow, such as precipitation and snowfall, remain the same in the changing climate?

No, say scientists, but whether that will lead to rise or fall of rivers' levels - and by how much and when - are the questions still waiting to be answered.

"We are seeing some changes in the monsoon," Dr Eriksson said of the seasonal precipitation system that shapes the climate in this part of the region.

"Last year, for example, the monsoon arrived one month late in Nepal and then some places saw 80mm of water in a day during the delayed rainy season.

"But there has been no consistent measurement of precipitation and temperature and there is a lack of proper studies."

'Heat trapping aerosols'

Some scientists believe absorption of solar radiation by aerosols (dust particles and carbon soots) can heat the atmosphere and accelerate regional impacts of global warming, which in turn affect water resources.

The monsoon plays a vital role in South Asian economies

William Lau, who heads the atmospheric sciences branch at Nasa's Goddard Flight Center, carried out a study in India last year and found that, as a result of aerosols, regional temperature was rising much faster than expected.

And that, he said, could influence the monsoon systems, resulting in less water availability in the region.

But Dr Armstrong said a warming climate could also mean a stronger monsoon bringing more precipitation that could increase stream flows.

"Having said that, it should be noted that future precipitation patterns predicted by climate models are highly variable and there is a very little regional agreement among the models," he said.

High variability is also an issue with the flow of rivers in the western Himalayas that do not fall within the monsoon regime.

"There is no clear-cut signal as there is a large variation between average annual flows," said Arshad Muhammad Khan, a physicist who heads the Global Change Impact Studies Centre in Pakistan.

"For example, in the Indus River, the maximum flow is twice of that of the minimum."

Unlike the Ganges, rivers like the Indus in the western part of the Himalayas are heavily dependent on glaciers, as this region does not get monsoon rains.

But even here, glacial status is not reported to be uniform.

Rising or falling flows?

Some scientists say increasing temperature has meant that glaciers don't get enough snowfall during winter and therefore river flow during summer is dwindling.

"We have seen the decline in the flow of the Indus, Chenab and Jhelum rivers," says Professor Mohammad Sultan Bhat of Kashmir University, who has conducted field studies with India's flood and irrigation department.

"We have recorded a decrease of 40% in the flow of Jhelum's tributary river… that is fed by the receding Kolahi glacier."

But, Kenneth Hewitt, a glaciologist from Canada who has been doing field studies in Pakistan's Karakoram mountains, told BBC News last October that he had seen at least half a dozen glaciers there advancing since he saw them five years ago.

With glaciers offering such complex pictures, combined with precipitation and temperature patterns becoming increasingly complicated, the region's river systems that depend on all these factors cannot be simpler.

Politics and geography, experts say, have made understanding the situation even more difficult.

"Some countries in the region are not willing to share water-related data because they regard it as confidential," said Dr Eriksson of ICIMOD.

"Since it is difficult to access them, proper studies on water availability remain a major challenge."