Thursday, May 3, 2012

This is to bring to your notice about the indigenous efforts of Indian scientists who developed a mass spectrometer based payload called CHACE for which I was the team leader. This was done during 2003-2008 at Vikram Sarabha Space Center of ISRO, India.

My core team was comprising of 5-young members below 30-years of age. Though, the ISRO like an ocean supported every bit of realization of CHACE. The feeling of seeing your instrument reaching the moon was so compelling that we were always walking an extra mile to reach our targets. We wrote to many many experts: Alan Stern(e-mail), who had written the review paper on the lunar constituents, Bob Hodges (Postal letter) who had built LACE in the Apollo mission. We got immense amount of information from both of them. Today, we owe a major chunk of our success to all the wisdom we gained from these selfless humans who worked very hard to explore the stellar bodies. I remember in one of Lunar Exploration Conference (ILWEG-2007, Sorrento,Italy), one Apollo team scientist was thanking god for hoping to see many more probes (ChangE-China, Chandrayaan-I-India) bringing wealth of new data from the fascinating heavenly neighbor.

We figured that though detected night time constituents of lunar constituents (for almost 8-months) the problem LACE faced in detecting the day time concentration of the ambient constituents was due to the large time slot assigned to collect each channel of data. Though the calculation was correct but due to the low dynamic range of their detection system, the detectors were "swarmed as the day kicked in" to quote Alan Stern.

Our detector had 8-orders of dynamic range; thanks to the present day technology; every decision of freezing the instrument parameter was challenged and final conclusion arrived only after a logical understanding of the issue, thanks to the ISRO culture.

On November-14th, 2008; when the Moon Impact Probe (of Chandrayaan-I)  data was transmitted back, the peak at 18 (H2O) was literally "pouring out" of CHACE. Our director, who was nearing 60, was jumping like a kid; we couldn’t believe for a while whether it was all true.

We tried very very hard to publish this "direct evidence of water" for the next 15-months; but nobody believed us. We could bring to publication only in Feb-2010; and even today many experts around the globe are unaware of the wonderful set of data CHACE payload has achieved.

Please do have a reference of those papers we have published; in case you find it interesting; you may please read the following blogs as well.

R. Sridharan, S.M. Ahmed, Tirtha Pratim Das, P.Sreelatha, P. Pradeepkumar, Neha Naik, Gogulapati Supriya
The sunlit lunar atmosphere: A comprehensive study by CHACE on the Moon Impact Probe of Chandrayaan-1

R. Sridharan, S.M. Ahmed, Tirtha Pratim Das, P.Sreelatha, P. Pradeepkumar, Neha Naik, Gogulapati Supriya
Direct evidence for water (H2O) in the sunlit lunar ambience from CHACE on MIP of Chandrayaan-I, Planetary and Space Sciences,58, 947-950, 2010