New Delhi, Feb. 23: A giant volcanic cave beneath the moons surface discovered by Indian scientists last year through an analysis of archived images from the Chandrayaan-1 spacecraft may be a candidate site for a future human habitat.
Researchers at the Space Applications Centre, Ahmedabad, analysed 3D images from Chandrayaan-1s Terrain Mapping Camera to identify the 1.7-kilometre long cave in a region of the moon called Oceanus Procellarum.
The hollow structure created by ancient volcanic lava flows on the Moon may provide lunar explorers a natural shelter from radiation storms and extreme variations between day and night temperatures encountered on the lunar surface, the SAC scientists said.
Their image analysis has revealed a hollow lava tube with a cavernous mouth — about 120-metres high and 360-metres wide —- and a roof estimated to be 40-metres thick. Details of the lava tube will appear tomorrow in the journal Current Science .
This is a monster cave, Ashutosh Arya, a senior geologist at the SAC, told The Telegraph .
The images also show two narrow trench-like structures that appear to lead into and out of the lava tube — a 4-km stretch aligned northeast-southwest appearing to move into the lava tube, and a 2-km stretch extending on the other side. The scientists believe these trenches, called rilles by geologists, represent the collapsed portions of what was once a much longer lava tube.
The hollow tube-like structure is similar to lava tubes observed on the islands of Hawaii, said Arya. But but we dont find a lava tube on the Earth as large as this one.
Such buried lava tubes are expected to protect human explorers as well as instruments from radiation storms as well as extreme variations in temperatures on the Moons surface. The radiation is not expected to penetrate beyond 6 metres of the roof thickness. While the day and night temperatures on the moon swing from +120°C to -180 °C, temperatures inside the lava tube are expected to be near-constant -20°C.
Such natural protection will help cut down the bill for future human habitats, said A.S. Kiran Kumar, a physicist at the SAC and the principal investigator for Chandrayaan-1's Terrain Mapping Camera.
The SAC team plans to continue using the archived images from Chandrayaan-1 to look for more such structures in different areas of the Moon. Were trying to generate a database for future generations of space explorers," Kiran Kumar told The Telegraph.
While the global space science community has shown a renewed interest in the moon, sections of scientists caution that it would be unrealistic to expect any long-term habitation efforts within the next two decades.
The SAC scientists had announced their discovery of the lava tube at lunar science conferences in Ahmedabad and Houston, US, last year, but have described their results in greater detail in the journal Current Science this week.
The Terrain Mapping Camera was among several scientific payloads aboard Chandrayaan-1, Indias first lunar orbiter, launched in October 2008, but which was lost several months later due to instrument failures.
Two years ago, Japanese scientists using images from Japans SELENE spacecraft had reported finding a vertical hole on the Moon, which they interpreted to be a possible lava tube skylight. Their analysis, reported in the journal Geophysical Research Letters , showed a nearly circular 65-metre diametre hole in a volcanic province called Marius Hills. The scientists had estimated the depth of the tube to be about 80 metres.
Junichi Haruyama and his colleagues had also proposed that such lava tubes may be potential sites for lunar outposts because they offer a much less harsher environment than the exposed surface.