Interview with M. Annadurai, project director, Chandrayaan-1 .
WITH Chandrayaan-1 realised and launched, we are technically ready to take up a truly interplanetary mission, says M. Annadurai, project director, Chandrayaan-1.
Speaking to Frontline on October 24 in Bangalore, he explained, among other things, the logic behind the mission, laying stress on locating water and helium-3 on the moon. Annadurai, 50, has a B.E. (Electronics) degree from the Government College of Technology, Coimbatore, and a postgraduate degree (M.E.) in the same discipline from the PSG College of Technology, Coimbatore. He took over as the project director of Chandrayaan-1 in 2004. He was mission director for all Indian National Satellite (INSAT) projects from 1996. Excerpts from the interview:
What are the reasons that dictated the choice of 11 scientific instruments on board Chandrayaan-1?
Our main objective was to provide a systematic chemical and mineral mapping of the entire moon. Over and above that, we are to look for resources on the moon. We made our instruments basically covering these objectives. The instruments we selected from abroad will technically overlap the returns from our instruments so that we can compare the results. That is why we have payloads for the optical region, near infrared region, low energy X-ray, high energy X-ray and even radio regimes. We received 26 proposals from abroad. We also looked at the real competence of each organisation in terms of the instruments they projected and their ability to match our schedule. On these merits, we selected two instruments from the U.S. and four from Europe [including one from Bulgaria].
Why is there so much of stress on confirming the presence of water-ice on the moon?
In case we have to start a human civilisation beyond the earth, water is the minimum requirement. The second [objective] is the possibility of exploiting some of the resources available in lunar soil. In that category come uranium, thorium and helium-3.
Former President A.P.J. Abdul Kalam has spoken about the possibility of harvesting helium-3 in lunar soil and bringing it to earth.
Soil samples brought from the moon do indicate an abundance of helium-3. This happened in the 1980s. Basically, the laboratory models of helium-3-based reactors also started around that time. Putting these two together, they again started going to the moon in the early 1990s. If you look at it logically, in another 15 to 20 years if this resource is available and if it [the fusion reactor] comes through, space technology can play a major role in bringing this resource from our nearest planet. Towards that, we have to build technologies in parallel and Chandrayaan-1 is the first step in that direction.
We will go closer to the moon, then land on the moon and enable technologies to move around the moon and logically extend these technologies to bring samples to the earth. If everything happens by the time the reactors are ready, we will be at a point where we can, together, provide an energy solution for the future. This is the thinking now.
What were the facilities that you established at ISRO Satellite Centre, Bangalore, for testing Chandrayaan-1?
We basically made use of most of the facilities that were already in existence. We augmented some of them and some we made new.
What did you augment and what did you make new?
Byalalu [with its 32-metre and 18-metre antennas] is a full-fledged new facility. The Indian Space Science Data Centre is also totally new. It will serve not only Chandrayaan-1 but future missions.
We augmented the clean room (at ISRO Satellite Centre where Chandrayaan-1 was built). We made the systems to provide the ultra-clean environment needed for Chandrayaan-1. This is the first time we have made science instruments that need an ultra-clean environment and have to be maintained without contamination for months.
Integration of the instruments went on for nearly a year and a half. We made special instruments/arrangements in the clean room so that the instruments were maintained in a very clean set-up. These called for instruments to be purged with nitrogen. Our engineers made these instruments and the set-up.
However, we had to ensure that the environment was conducive to engineers and scientists working there because nitrogen could harm them. So we had to monitor and control the environment during the entire period of one year and a half in the clean room. This called for a new set of monitoring and control instrumentation in the clean room where Chandrayaan-1 was kept most of the time.
Then there is the thermo-vacuum chamber. The earlier spacecraft had to work in an earth environment whereas this spacecraft has to work in the lunar environment. Even while retaining the existing chamber, we had to make special instrumentation so that Chandrayaan-1 is tested in the simulated lunar environment. So our engineers, in an ingenious way, simulated the thermo-vacuum environment.
We simultaneously made new calibration facilities for some of the new scientific instruments we built ourselves and for those our collaborators brought.
Although Chandrayaan-1 is not treated as an interplanetary mission, we have used this opportunity because it is travelling 3.84 lakh kilometres away from the earth to include some of the technologies and ground instrumentation required for interplanetary missions. So Chandrayaan-1 is like an interplanetary mission as far as to and fro communication is concerned. This means, with Chandrayaan-1 realised and launched, we are ready technically to take up a truly interplanetary mission.
Did you face any difficulties in integrating the payloads from abroad into the spacecraft bus? What is the reason for the delay in launching the spacecraft when you had announced that it would go up on April 9, 2008?
No [there were no difficulties]. If you look at the delay, there were two reasons. As and when the instruments came, we integrated them. When I said it would go up in April, I had announced it long ago, I purposely announced a schedule that was one year ahead of the realisable schedule.
Our project report talks about a five-year schedule. The budget was cleared in September 2003 and the project was really formed in April 2004 and will complete five years only in April 2009. I launched the spacecraft in October 2008, which is four years and a half from April 2004. So, first of all, it is not a delay.
Secondly, why did I go from April to October 2008 a delay of six months? As I pointed out earlier, my schedule was ambitious. We thought if the instruments kept coming in, we would be ready as per the schedule. When we add an instrument, it slightly disturbs the previous instrument already integrated [into the bus]. This is a risk. But we have to ensure that all the instruments work in tandem. You cannot correct the instrument that has already arrived. You have to correct the interface only. You have to arrange your house to accommodate a guest. You cannot ask the guest to change himself to suit your house. We have to make sure that things suit our guests.
It was not one or two instruments but 11. Matching each others needs takes its own time. Accommodating 11 instruments is not easy. Ours is a reasonable schedule because this is the first time we are making such instruments and this is a full-fledged mission. The spacecraft has to match not only our instruments but the newly set-up Deep Space Network. Whatever interaction takes place, it has to take place in the spacecraft also. It has to go in tandem.
You have to look at the PSLVs [Polar Satellite Launch Vehicle] constraint also. I cannot say that I want the rocket to lift 1,500 kg or 1,700 kg. That limit also has to be kept in mind. If you look at these constraints, we have done a reasonably good job. I dont think we are delayed.