Tuesday, April 16, 2013

Yes, Moon has Atmosphere

I must thank Tim Berners-Lee who has brought www into this world. It is due to him that I am in a position to bring to the notice of entire humanity about a clarification, I intend to showcase our work in the Moon Impact Probe (MIP) mission of Indian Lunar project, Chandrayaan-I. The title of my blog is in response to article appearing (12th April, 2013) on Space Fellowship (Spacefellowship.com) by Klaus Schmidt titled  Is There an Atmosphere on the Moon. It is quite intriguing that in the well informed world of information flow, our work of peer reviewed journal (Sridharan R, Ahmed SM et al, 2010) on the sunlit Lunar Atmospheric measurements are ignored; the author has tried his best to suppress his emotions, however the attempt here is to bring out an historical event which has brought a radical shift in the assumption of bone dry moon concept.

Our article appearing 14-months after the observations were obtained

An enormous effort put up by a hand picked group of young Indians building the science instrument (CHACE, CHandra's Altitudinal Composition Explorer)  in Chandrayaan-I, for the FIRST TIME,  measured the tenuous atmosphere which was prevailing on the Lunar atmosphere. In technical jargon the measurements were in-situ (on site measurements) observations as the instrument had its 22-minute journey after its separation from the mother space craft till the hard landing on the southern lunar pole. In a very brief summary: our instrument not only measured the lunar atmospheric constituents for first time ever, but also brought a huge change in the old mind set of bone dry moon. As against the earlier ambient pressure measurement limits achieved by CCIG  (Cold Cathode Ionization Gauge) measurements to a value of 10 (-10) torr; our instrument measured a highest value of 6X10 (-7) torr; which is 1000-times higher than ever thought. The Apollo era (to which Dr.  Schmidt refers) had always had doubts whether there was an atmosphere on the Moon as their mass spectrometer, LACE,  which were left on the lunar soil were always getting "swarmed" as the sun rises on the moon, as referred by Alan Stern in his famous Space Science Review paper (The Lunar Atmosphere, Review of Geo-Physics, 37,453, 1999). This was purely due to the very large integration time chosen by the LACE team members in the anticipation that the prevailing conditions were very very rare (extremely less dense).

As a science team member of Chandrayaan-I, during my stint with ISRO (2003-2008); we developed a most sensitive quadrupole mass spectrometer (CHACE) ever to be placed in the space. The details on the development of this wonderful baby is described in my earlier blogs CHACE (instrument) and the immaculate results this instrument has brought are narrated (CHACE Results) . For some strange reasons the Western world ( CHACE data ignored ) has always been sidelining the work which was published by a reasonably well respected journal ( Planetary and Space Sciences, 58, 1567-77, 2010in the planetary exploration community from UK.

Let me again reiterate that along with the aspiration of billion Indians, some 5-6 of young team members were always walking an extra mile to see their instrument be placed on the Lunar soil. We chose the most sensitive mass spectrometer available (which can measure 10 (-14) torr pressure), the instrument was offering the widest dynamic range, thanks to the available technology in 2006. We read each and every available document on the public domain on the exploration of lunar "atmosphere". We consulted the most experienced (Bob Hodges, LACE, Apollo Scientist, Alan Stern, expert on lunar ambiance  SWRI ) human brains who have worked on the past lunar explorations. Each and every element of resource available in ISRO was utilized. Today if I look back, it appears that every step we had taken was meticulous and purely on technical merit; indeed it gave us the most fruitful results humans had ever seen.

Alas.... even today there is complete darkness on the wonderful results our baby CHACE has brought. I will be very glad to offer the entire set of work which has been published  and also to give any further explaination. May be.. thanks again to Dr. Schmidt that the experts in this field read this piece of information and have some appreciation for their fellow scientists on the other side of the globe.

S.M. Ahmed, team leader, CHACE instrument.

Our baby: CHACE

Total Pressure measured during the decent made by CHACE