My Tryst with Chandrayaan-2

LusseX Deployed

While I was trained as a Nuclear Fusion Scientist and spent nearly two decades working on Nuclear Fusion in USA and India, I moved to Dhirubhai Ambani Institute of ICT(DA-IICT), Gandhinagar in Gujarat in the summer of 2002 as  Professor to enlarge my area of work. Considering the focus areas of DA-IICT, I felt that I could work on Robotics to help manage the remote control requirements of Nuclear Fusion Reactors. As I was going through the literature on Robotics, I started to see the scope of a group of Robots linked by communication and working in a cooperative manner. From here I stumbled upon the concept of Wireless Sensor Network(WSN) or Sensor Network.

Please see some of my earlier write-ups:

(a) How I got into Nuclear Fusion Research 

(b) How I Became Accidental Experimentalist!

WSN consists of a large number of “Sensor Nodes” having sensing, processing, and communication capability along with a power source(mostly battery). Most of the time, these nodes are untethered so power saving is a crucial requirement. Almost 95% of research work globally is focused on saving energy. I started developing the basic capability of technologies related to WSN while looking at its possible application areas. I initially realized its potential for Agriculture and started collaborating with Reliance’s Agro Initiative in Jamnagar.

At the same time, WSN was gaining popularity in the tracking of Wildlife. The great Duck Island project of Berkeley and the Zebranet Project of Princeton were examples of this. We also started working in this area and quickly collaborated with the Wildlife Institute of India, Dehradun on a number of projects around 2006-07.

Sometimes I used to be invited to Space Application Centre(SAC), Ahmedabad to give special talks to incoming employees. During one such talk during 2006-07, I talked about my work on WSN, and at the end of my talk, I wondered if this technology would have any use in Chandrayaan Mission of India since I did not know much about the mission. My host, Prof K S Dasgupta, told me that ISRO was basically a transporter of payload and I should talk to Physics people, who design the payload to go on the mission. He mentioned that the Director of the Physical Research Laboratory(PRL), Ahmedabad, Dr J Goswami was the Chief Scientist of Moon Mission and he may be the right person to talk to in this regard. I contacted Dr. Goswami’s office to get an appointment. Dr Goswami came on the phone and talked to me for 15-20 minutes and said that concept looks interesting but he is not sure how it can be useful on Moon Mission. I kept talking about the possibility of use of WSN on Moon Mission, whenever I got an opportunity.

In Oct 2007, I was in Spain at SENSORCOMM 2007 conference, when I received an email from PRL stating that they are having a meeting to discuss the payload for the Chandrayaan-2 mission and if I could come over. I replied back that I am out of the country and would contact them after return. After returning, I contacted the Head of the Planetary Exploration Group of PRL, Prof Murty. He explained that one of the key research objectives of the Chandrayaan mission is to locate sources of water on the moon. One of the possible locations is permanently shadowed regions(PSR) of the moon. In particular, a few craters in the polar region of the moon may hold water. During meeting, they were discussing if my suggestion of using WSN can help in this. After the discussion, I offered to give a talk on WSN and continue the discussion to work out the possibility of using it to detect water on the moon. In Nov 2007, I gave a talk on the concept of WSN and my work on applying it to different domains. Dr. Goswami encouraged me to work out the proposal in detail. I along with Scientists from the PRL Planetary Exploration group worked on the idea and after several rounds of discussion, came up with a full proposal. Dr Goswami suggested me to take up the responsibility of Principal Investigator (PI) with the PRL team as Co-PI. We formally submitted the proposal.

After the successful launch of Chandrayaan-1, newspapers published our idea

Coverage in the Times of India:

The idea that we had proposed was something very unusual. We wanted to throw a few sensor balls(nodes) into the PSR region like a projectile. Once they land there(one had to make it safe to land), they would work on detecting ice and form a network among themselves and communicate findings to orbiter or lander depending upon communication links. Temperatures are expected to be close to -200 degree Celsius so the nodes would not survive for long. They had to perform their task quickly and send out the data as fast as possible. This is depicted in the image below:

Water Detection on Moon

After the formal submission of the proposal, sometime in 2008-09, the presentation of all shortlisted proposals was arranged in PRL to a committee formed for finalizing the payloads. I was also asked to make the presentation on WSN proposal. When I was part of the way making a presentation (maybe about 5 minutes had passed), the Chairman of the committee told me – ” You sit down. You are talking nonsense. How can you a make sensor node in 150 gms? I guarantee that it cannot be done in less than 6 Kg.”. After the intervention of Dr Goswami, I was allowed to complete my presentation. Our idea was so much out of the box that it was difficult for experts to accept. However not only proposal was funded but in the review after one year, the same Chairman was supporting the proposal. What a change of mind! We received confirmation of approval of funds sometime in March 2009. We started to work on the proposal. One of the key elements was to develop a sensing mechanism that would detect water in a miniature device as per the need of the project. We roped in SAMEER a Govt of India organization based in the IIT Bombay campus for this purpose.

After about 3 months time, during the summer vacation of June 2009, I was in my native village, Narayanpur in Darbhanga Dist of North Bihar. The village is quite remote and for the first time, I could connect to the Internet using a Dongle. One of the emails that I received was from Space Advisory Board(SAB) asking for proposals for CH-2 to be submitted again. I was a bit surprised since we already had been allocated funds. After returning to Gandhinagar, I got in touch with PRL to find out about the resubmission of the proposal. I came to know that the CH-2 mission was a collaboration between India and Russia. Russia was to supply Lander and Rover. The payload was to be shared between the two countries. India was given a payload of 15 kg on the lander. Part of this could be on Rover and part on Lander. India decided to develop a mini rover and send it along with the Russian rover. This would have a mass of 13 Kg. This meant that India was left with only 2 Kg additional payload for the rest of the experiments. In view of this, it was not possible for the WSN-based water detection experiment to be sent as a payload since it would have taken up 5-6 Kg.

While we continued to work on the Water Detection project, I needed to come up with an alternate proposal considering the reduced payload possibility. During one of the discussions in PRL, a senior Scientist met me during break and suggested that while the detection of water on the moon is important, it would be even more valuable if we can measure seismic activity using WSN. This would help in understanding the origin of the moon. I met him again and discussed in detail and made a proposal for measuring Seismic Activity using the WSN concept. I also had an opportunity to visit California in Aug 2009 since my team had won the HP Innovate 2009 award and all of us went on a sponsored trip to HP Labs in Palo Alto, CA. I managed to visit Jet Propulsion Lab(JPL), Pasadena – one of the key national labs of NASA to discuss my proposal for Seismic Sensor Network.

At that time Rover planned by ISRO could only move a maximum distance of 10 meters in 24 hours. I wanted to be able to spread Seismic sensor nodes as far as possible to get information from greater depths of the moon. After discussion, it turned out that even a separation of 10 meters was ok to get information about the subsurface structure that would be useful for construction activity on the Lunar surface. After finalizing the proposal in detail, I submitted it formally. One of the key issues was a very good modeling effort to interpret data collected from Seismic sensors. In addition, the Seismic noise floor on the moon is an order of magnitude lower than Earth. Seismic activities recorded by Apollo Mission had seen a maximum of about 5 to 5.5 on the Richter scale. So very sensitive seismic sensor was needed to get a good recording. No Seismic activity measurements were done after Apollo Mission. I could manage to get in touch with Dr. Tom Pike through a common friend, who had developed a very sensitive seismic sensor at JPL and later on moved to Imperial College, London. I also visited NGRI, Hyderabad to give a talk on the Seismic Sensor Network plan to see if they could participate through the use of modeling techniques, etc. No one in the world was working on Lunar Seismic Activity as no data had been collected after Apollo Mission. One American scientist, who had done PhD in this area had moved to some other field and advised me to be in touch with a Japanese group. The Japanese group suggested working in collaboration since they were also starting and were at an early stage.

While I was working on both these ideas of detecting water and measuring lunar seismic activities, I got an email to give a lead talk in the Planetary Exploration Session of the National Space Science Symposium (NSSS- 2010) on Feb 24, 2010 at Rajkot. I was a bit surprised about me being invited for such a talk since I was very new to planetary exploration. But organizers said that everyone felt that I was the right person to give a talk on “Emerging Technologies for Planetary Exploration”.

Invitation Letter for NSSS-2010

In the meantime, I had re-established contact with my long-time friend and apartment mate, Dr Tom George, who had spent a considerable amount of time at JPL. During my visit to California, I could not meet him personally but he visited me in India and spent a day. He gave a talk at DA-IICT as well as we talked till late at night about various work he had been involved with. His inputs were of great help to me to prepare the talk. The talk at Rajkot went well and was appreciated since it showed newer possibilities. Here also I could sense some murmurs that I could not follow. An ISRO delegation had visited Russia in connection with CH-2 collaboration and they had come to Rajkot after that. But I could not get a sense of what had happened.

After about 3 weeks, I received a mail from one of the ISRO scientists saying that there is some change in CH-2 mission plans and they wanted my help to develop a new proposal to carry out experiments on Rover. A brief sketch was enclosed about what they had in mind.

The first communication from ISRO regarding the changed plan and design of LusseX

Again, I was very surprised since it required one to integrate or develop a large number of instruments and package them together in a highly optimized way. The total available mass was 5 Kg with a power of only 20 Watts. I was taken aback by the magnanimity of the project. I called back Scientist to check if it was indeed meant for me! He said yes and they felt that I was the one who could do it since it requires very innovative thinking. I requested him to make arrangements for me to talk to CH-2 Mission Director. We did teleconferencing after a couple of days with the full CH-2 team. I felt that they were serious about my taking it up! They did provide me with details of some of the International Experts, who had worked on systems which could help with a few of the systems.

I got onto the task and after a few days visited Bangalore to have face to face discussion. In the meantime, I had done some preliminary work and had 3-4 hours of discussion with the full team. They appreciated my effort and requested me to come up with a full design along with technical details in one month’s time so that it can be put up to the appropriate committee urgently.

I got in touch with some of the international experts. One of them, Shaun Whitehead, agreed to give his full one-month time to me free of cost. He was involved with Beagle-2 Mission of the UK as a Systems Engineer. Many others agreed to help and we had frequent interactions with the CH-2 team. For one month, I could not see day or night. I could only use emails and Skype Audio calls. Rapid communication was key to meeting the time deadline. One of my cousin sister and brother-in-law were visiting us during the same period. She used to see me working when they were going to sleep and they used to notice me awake in the morning when they woke up. She used to wonder if I sleep at all!

Finally, with all the effort, I could prepare the full plan within the deadline and hand it over to CH-2 team. I am reproducing Cover Page, Preface, Acknowledgement, and Summary page from the proposal here. When it was put up to the committee (Where I was not present), it was felt to be a good design. However Russian collaboration was still not formally out and the committee decided to put it on hold till a formal decision about the Russian involvement was taken. I did request CH-2 team to manage some funds in the interim period so that technical work could start but unfortunately, they could not do that. I did continue my work on the detection of water using WSN knowing fully well that it would not be going on a mission but technological development would help in future missions.

Cover Page of LusseX Proposal
Preface to Proposal
Summary of Proposal

On Aug 31, 2012, I got a call from Dr Kiran Kumar, Ex-Chairman, ISRO and then Director, SAC, Ahmedabad to visit urgently for a discussion related to the Chandrayaan-2 mission. I was preparing a question paper(MCQ style) for an exam the next day for my students and was working from home to avoid any disturbances. I was wanting to visit the next day afternoon after finishing the exam. However, Dr Kiran Kumar wanted me to visit the same day and was willing to wait till late evening for a meeting.
I managed to reach SAC around 6:30 PM. I found out that the Chandrayaan-2 mission was undergoing major change due to the withdrawal of Russian Collaboration and hence India had to develop its own lander. Chairman, ISRO wanted to know the progress on the LusseX device, which as mentioned above was to do all in-situ experiments on Moon after landing on the moon. I explained that as funds for the purpose were not made available, i had not taken up further work. By that time, I had already accepted to head India’s Technology Think Tank, TIFAC in Delhi and critical work for developing Technology Vision 2035 had already been started by TIFAC. Dr Kiran Kumar attached two SAC Scientists to work with me till the time, I was in Gandhinagar. I shared whatever details I had till then. However, 2-3 months’ time was not enough to make sufficient progress on actual development. After moving to Delhi, I was not in further communication on this mission though this system is still of great importance and if fully developed, can help in many future missions. I do understand that a Seismic Sensor has been added to the lander, designed by NGRI though not sure about its coupling to lunar ground since NASA had faced a lot of problems with coupling on MARS. My design had taken that into account and made arrangements for its good coupling to the lunar ground. Around 2014, I did try to see if CMTI could take up some of the development but it did not work out. In the meantime, I was very busy with my work at TIFAC, which kept growing day by day. However, I always tried to keep tabs on CH-2 progress. I was happy when finally after a few delays, launch dates were announced. I arranged for my whole campus to watch the event live in a big auditorium. One could sense the enthusiasm of the students!

A few days back, the whole nation was glued to TV at late night to witness the landing operations(which ran into a bit of trouble at the last stage), I felt that I must write my experiences of involvement with this mission even though that link broke long back. In space missions, the chances of the launch of a project and its successful operations are very less since it is a one-time event and there is no opportunity later.

I wish that Lander starts to communicate miraculously and even if nothing else happens, we get access to any additional data that is stored there. it would be very useful for future lander operations. Of course, the orbiter seems to be doing very well with enough fuel to last 7.5 years! This would give plenty of time to collect a huge wealth of information.

Author: Prabhat Ranjan

Prof. Prabhat Ranjan is Vice Chancellor, D Y Patil International University, Akurdi, Pune. He was heading India's Technology Think Tank, TIFAC( as its Executive Director since April 2013 to April 2018. Earlier he was Professor at Dhirubhai Ambani Institute for Information and Communication Technology, Gandhinagar (DA-IICT) since 2002. He was educated in Netarhat School(near Ranchi), IIT Kharagpur and Delhi University. He received his Ph D from University of California, Berkeley where he carried our research on “Nuclear Fusion” at Lawrence Berkeley Laboratory during 1983-86. He immediately returned to India after this and carried out research in Nuclear Fusion area at Saha Institute of Nuclear Physics, Calcutta and Institute for Plasma Research(IPR), Gandhinagar. He played a major role in India’s Nuclear Fusion program and was Project Leader of the largest operational Indian Fusion Reactor, ADITYA, at Institute for Plasma Research from 1996-2002. His current interests include applications of Wireless Sensor Network to Wildlife, Planetary Exploration (Chandrayaan mission), Nuclear Fusion, Healthcare, Agriculture etc. He has received National Science Talent Search Award, IBM Faculty Innovation Grant and HP Innovate 2009 award, NPEDP-Mphasis Universal Design Award 2012, Bihar Gaurav Samman 2012 etc. In March 2022, he was also honored with EduStar India’s Most Impactful Vice Chancellor Award for 2021-22. He has been recognized by outlook among few visionaries, who can lead India towards 5 Trillion Dollar Economy. He has been also honoured with Maharashtra Ratna Gaurav Puraskar by Shalini Foundation in 2024. He is also recognized among the top “100 Great IITians : Dedicated to the Service of the Nation”.

28 thoughts on “My Tryst with Chandrayaan-2”

  1. Chand Ko to hum bhi pana chahate hai.
    Well said. You are real motivation and lucky to have your guidance

  2. R/Sir, your contribution is so multifarious; can’t imagine.You have been telling quite often about this.Our good wishes for your advise that will be demanded by the concerned.
    Tilekar S.N.

  3. The association of Professor Prabhat Ranjan with Chandrayan 2 has been significant. The nation is indeed excited about getting access to any data that could be stored in the lander. Be that as it may, the wealth of information that we would get through our orbiter, over the 7.5 years, or till the fuel lasts, has the potential to be what we call common heritage of mankind.

  4. My heartiest congratulations Sir, for the part of Team of Chandrayan-2 for successful launch of India’s Historic moon mission from Sriharikota.Regards

  5. Great Prabhat ji. You got interested in scientific exploration of possibilities at very early age and chose to be a scientist instead of an IAS. You also chose to come back from US and work in India. A great gesture. Our mother India must be proud of this son. Country has been benefited a lot by your presence here in different roles, including head of prestigious institutions like TIFAC. Now as VC, I see you are charting out innovative syllabus for technical education which will be benchmark for other universities and will help in enhancing effectiveness of technical education imparted at the campus. This effort of appropriate syllabus design will have multiplier effect. I wish a long, healthy and eventful life to you and your memorable contribution for our motherland. With best regards & love- Vinay Bhushan Gupta, AGM, BEL and NOBA(1972-78)

  6. My heartiest congratulations Sir, for the part of Team of Chandrayan-2 for successful launch of India’s Historic moon mission from Sriharikota.

  7. From this report of Prof. Ranjan , we can easily sense his line of thought, his line of purpose and his sheer passion for perfection. There is a lot a student can learn from his fantastic feat. Innovation in design under time stress is something which makes legends. We are very lucky to read this special right from Prof.Ranjan himself. Kudos to him for his efforts. Another thing worth noticing, are the changing milestones and changing specifications/ requirements. Very very interesting with edge of the seat suspense like a James Bond film.Thanks for sharing your experiences from all of us. Regards

  8. It is a matter of great pleasure to know how ideas and technological outcomes can evolve from challenges. Reading about your involvement and interaction during the CH-2 mission was a fascinating reading. WSN for water detection and also seismic activity detection is indeed a great concept and challenging to integrate with low power use, while water sensors can work intermittently the seismic sensors have to be active all the time and their detection capability can be multiplied if formed into an array while water sensors have no such limitations. India has such gifted, dedicated and committed persons like you that given the goal we can come up with optimal design. Sincerely wishing this program success to make new findings for the science.

  9. Many congratulations for the work.
    Very happy to know that u contributed so much for the mission

  10. Excellent Sir and feeling proud we are working with such an Eminent personality !!!!

  11. With yr contribution for CH-2,
    We ,the people of mithilanchal feel proud.Congrats sir!
    Request to establish a scientific centre at Darbhanga under the banner of Dr P Das Foundation,where we wuould able to enhance “Science for Society”concept.
    Vice principal(Retd.)
    Navodaya Vidyalaya Samiti.

  12. Congratulation sir for your great idea in chandrayan 2.we fill proud on you sir.Thanks lot sir.

  13. What a great contribution, wonderful idea of WSN, throwing sensor node in Crater on moon surface.
    Salute Sir

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