JOIN USNASA finds craters filled with ice on moon
Mini-SAR, an instrument belonging to the United States, on-board Chandrayaan-1, has detected telltale signatures of 600 million tonnes of water-ice trapped under the soil of 40 small craters typically with a diameter between two and 15 km, in lunar north pole, NASA said in a press statement after publishing the findings in the journal Geophysical Research Letters on Monday.
But it is too early to celebrate as numerous technical hurdles need to be overcome before that ice can be harnessed for future manned lunar mission.
Numerous craters in the lunar poles have interiors that are in permanent sun shadow. These areas are very cold, where water ice could possibly exist. But signatures were missing so far.
In fact, Japanese lunar probe Kaguya (Selene) in 2008 reported that these craters are unlikely to have water-ice dampening the spirit of lunar enthusiasts. The Japanese probe looked at the Shackleton crater in south pole, which was thought to be a likely place to find out water-ice.
The first good news came last year when another Chandrayaan instrument found plenty of water in molecular form on the moon bringing an end to the moon’s bone-dry image. Now mini-SAR’s spotting of water-ice, makes it even more wetter.
Between February and April in 2009, mini-SAR mapped almost 95 per cent of lunar pole up to a resolution of 150 mt.
Analysis of those images— long after the loss of Chandrayaan—reveal the water-ice signature, consistent with the sites identified NASA’s earlier probe lunar prospector.
However, Indian researchers differ with NASA conclusion on the quantity of ice.
“I don’t know how did they (NASA scientists) quantify. Mini-SAR can only detect signatures on water-ice by seeing from above. It can not quantity,” R R Navalgund, director of Space Application Centre, Ahmedabad SAC told Deccan Herald.
Incidentally, the estimated quantity is not a part of the GRL paper which NASA’s Paul Spudis co-authored with SAC scientist M Chakraborty and 30 others. Chakraborty is upset with NASA for jumping the gun, though he is not available for comment. The US space agency, surprisingly, let the water-ice estimate known through a press-statement without disclosing how the estimate has been calculated.
NASA said that mini-SAR may have underestimated the total quantity of water-ice, as some of the polar ice is mixed with lunar soil and thus, invisible to the radar.
Notwithstanding the controversy, the discovery coupled with other Chandrayaan and another NASA probe (LCROSS) indicates that water creation, migration, deposition and retention are occurring on the moon, said an Indian Space Research Organisation official.