Note: I wrote this on my earlier blog hosted as http://parallelspirals.blogspot.com. I recovered the text from the WayBack Machine. This post appeared on February 24, 2011 as per the time stamp. I’m trying to collect here again all my old writings spread on various blogs.
The current edition of Current Science magazine has the paper by Arya et. all titled, “Detection of potential site for future human habitability on the Moon using Chandrayaan-1 data“. The result itself was reported way back in March, 2010. The paper provides more details and some interesting facets. The paper is based on work done by the Terrain Mapping Camera on board the Chandrayaan-I spacecraft.
The high spatial resolution of the Terrain Mapping Camera and the close 100 km orbit helped scientists build Digital Elevation Models (DEM) to help study the lunar terrain in great detail. This was used to study potential human habitability sites on the Moon. Based on previous studies, they concentrated their efforts on riles and lava tubes on the lunar surface. Study on the Oceanus Procellurum region on the Moon showed that lava tubes were good places for possible human habitability. They found that there was no effect of cosmic rays deeper than 6 meters, no effect of solar particles deeper than 1 meter, no radiation effects and no significant temperature difference was observed with the temperature remaining nearly constant at -20 degrees Celsius. It is also opined that the presence of partial lava tube structure reduces requirement of construction. Scientists also think that the cool temperatures here could make these a candidate for water and ice traps on the lunar surface. Lava tubes also provide a dust free environment.
Lava Tubes are interesting to study for reasons other than human habitability as well. To geologists, it provides a section of the lunar bedrock and top soil that would be difficult to access otherwise. It could also help geologists to study native lunar material which has not been affected by external factors like meteoric impacts, solar particles etc. It could also provide an understanding of the thermal profiles and volcanism on the Moon.
The paper now profiles the area of the Moon under study, Oceanus Procellurum using a picture of the Moon taken by the CARTOSAT-2A spacecraft from Earth orbit!
Using various techniques (explained in the paper) they find that the rough cylindrical tube which comprises the lava tube is 120 meters in diameter and 1.72 km in length. The thickness of the roof is 170 meters hence safe from various considerations discussed above (radiation, cosmic rays etc.). The Hyper Spectral Imager (HySI) was used to do chemical and mineralogical study. It was found that the surface was homogeneously basaltic rich in Iron and Titanium. The homogeneity of the results was also used to predict that there was no lava flow after the lava tube was formed. To confirm the result, surface ages of the north and south section of the uncollapsed rille was done using the crater counting technique. Using this method ages of the northern section was found to be 3.47 Ga and the southern section was found to be 3.43 Ga. This more or less rules out “differential emplacements of the mare basalts”.
The authors of the paper state that using similar procedures, TMC and HySI data can be used to study different areas on the surface of the Moon.