Interview with G. Madhavan Nair, Chairman, ISRO, and Secretary, Department of Space.
AROUND the world there has been a renewed interest in exploring the moon's surface. The Japanese and the Chinese will send spacecraft to the moon. The Americans will launch a lunar reconnaissance orbiter in 2008. In India, the Indian Space Research Organisation has its own plans, G. Madhavan Nair, Chairman, ISRO, and Secretary, Department of Space, told Frontline in an interview at his office at ISRO headquarters, Bangalore, on November 20. In the first quarter of 2008 it plans to send the spacecraft Chandrayaan-I into the moon's orbit, which will drop a Moon Impact Probe onto lunar soil. A subsequent mission will land a robot capable of doing its own chemical analysis and sending the results to the earth.
ISRO is evolving plans to send an Indian into space. As a first step towards this, it will launch a Space Capsule Recovery Experiment (SRE) from Sriharikota in January 2007, Madhavan Nair said. Excerpts from the interview:
So far, ISRO has sent satellites into a geostationary transfer orbit at a height of 36,000 km by 180 km. But its spacecraft Chandrayaan-I will orbit the moon, which is about 3.8 lakh km away from the earth. What technological challenges do you foresee in covering such a great distance, in navigation, in building propulsion systems and so on?
Unlike previous launch vehicle missions, we will not be able to have an autonomous navigation and guidance system for the Chandrayaan-I mission. We have to depend heavily on tracking carried out from the ground station. Towards this, we are establishing a Deep Space Tracking Network at Byalalu near Bangalore. It will be our own station. Maybe, for the initial phase, we will draw support from one of the stations outside [India] to provide continuous support to receive telemetry, send telecommands and fix accurately the trajectory parameters. Even after getting these data, one has to go through a large amount of processing to remove the noise and arrive at the appropriate coordinates. So this is going to be the first of its kind. We have not experienced tracking a spacecraft to distances more than 36,000 km so far - decision-making will be important.
The propulsion system we are going to use in Chandrayaan is similar to what we are using for INSATs. So far we have had minimum uncertainties on that count. We hope we will be able to carry out a number of simulations and validation tests well before the launch so that we can have a systematic launch operation for taking the spacecraft to the moon.
Besides sending Chandrayaan to orbit the moon, you are going to land a probe on the surface of the moon. In what way will this Moon Impact Probe be useful for future missions?
The impactor is essentially to evaluate the lunar trajectories. When we send the spacecraft to the moon, the gravitational field will have a strong influence on its [the spacecraft's] orbit. We have some inputs available on this based on past missions. But when the spacecraft orbits the moon we will get some data on this. Using these, we will try to define a trajectory for the impactor. That will be one of our major experiments. As the impactor descends, it will take closer pictures of the lunar surface and when it impacts, it will kick up some dust. Using the mass spectrometer, we will be able to get the signature related to the composition of the material that covers the lunar surface. This is the first step towards later missions, which that will require a soft landing and a robot, experimental set-up to analyse and return the data.
So will the future ISRO mission land a robot on the moon?
We are trying to conceive of an experiment in which the system will land on the lunar surface, move around and pick up samples, do their chemical analysis and transmit the data back to the ground.
How important is the Deep Space Tracking Network for future missions to the moon? You have already installed a satellite antenna with a dish diameter of 18 metres at Byalalu to track Chandrayaan, and you are soon going to erect one with a diameter of 32 metres. ISRO is going to invest Rs.100 crores out of Rs.386 crores for the Chandrayaan-I mission on the Deep Space Network. Is it a sound investment and why do you locate it near Bangalore?
First of all, the Deep Space Network is going to be a national effort. It is going to serve not only the moon mission, but other spacecraft missions at a later date, such as one to Mars.
Secondly, the technological challenges associated with developing large antenna systems, accurate tracking systems and so on, are providing a challenge to the technical people at BARC [Bhabha Atomic Research Centre], ECIL [Electronics Corporation of India Limited] and ISRO. Thirdly, it will provide us with the opportunity to offer our support to other countries if they have deep-space missions.
How do you explain the revival of interest now in exploring the moon's surface?
Earlier, lunar explorations were driven by national prestige. The United States wanted their man to land on the moon and they achieved it. Russia [Soviet Union] concentrated more on sending robots and instruments to the moon. These explorations were more or less confined to the equatorial regions of the moon. At the same time, there was a lot of scientific interest in studying the entire lunar surface, especially at the poles, where it is hypothesised that there is some trace of water. But there is no clear proof as yet. All this provides a lot of interest to the scientific community to explore the moon. This is one of the driving forces.
People are also looking at whether the minerals on the lunar surface can be economically exploited. It means a lot more data are required on the abundance of various elements and on whether it is feasible to mine them and bring them back.
Besides, if we want to travel further to other planets, such as Mars or even to the outer solar system, an intermediate base may be required. From that point of view, a lunar base will provide us with an opportunity, and this again is one of the driving forces.
Above all, trying to understand the moon will help us try to understand the origin of the earth and its evolution. This is because it is believed that the moon spun off from the earth at some point of time in its evolution.
The present political leadership of India is keen on sending an Indian astronaut into space. Is this because it wants India to catch up with China, which has already sent its astronauts into space?
You are perhaps reading too much between the lines. The first thing is, any such project normally goes through a review process at all levels. In fact, we are in zero phase, where the concepts are being evolved. They are being projected to the scientific community and the latter's viewpoints for and against such a mission are being received. We are trying to evaluate the benefits and the costs involved, the type of technological maturity required, the infrastructure required and so on. Based on this assessment only can we go to the government and seek its permission for going ahead with such a programme. We hope that in a year's time we will have convergence on all these issues. Once we have clarity, we will be able to submit a report to the government.
In January 2007, ISRO will launch a PSLV from Sriharikota, which will orbit the Space Capsule Recovery Experiment (SRE), a recoverable satellite. In what way will this SRE be useful for a manned mission to space?
The SRE is a small capsule to demonstrate zero-gravity experiments and the results (payloads) in the SRE will be recovered. But a capsule for a manned mission has to be much bigger. Compared to the 500 kg capsule for the SRE, the manned mission capsule will weigh a few tonnes, three to four tonnes at least. Also, the type of requirements for the life-support systems, the radiation environment, zero-gravity and so on will be very complex. So the manned mission is an order of magnitude higher than that of the SRE. Some inputs related to the breaking of the orbits, bringing the capsule back to the surface on a safe mode and so on, will form the inputs for the design of a manned capsule.
What challenges will you face in sending a man into space?
Plenty. It will be a major driver for technology development in the country. The launch vehicle has to be made more reliable than it is today. We don't want to take risks with human beings. Then there are the launch, abort and rescue systems. In any part of the mission, we should be able to rescue the astronauts from the capsule and bring them back to the ground in case of any problem with the mission. Thirdly, we have to design a capsule which can withstand the launch environment, later the space environment, especially the severe radiation and vacuum conditions, and the capsule should have life-support systems for food, water, waste management and so on. A host of new elements need to be developed. Training the astronauts will need a big infrastructure [development] in aero-medicine, in simulations for various conditions and in evaluation courses. We believe that these will be a real challenge for the entire scientific community, not only within ISRO but also outside.
After the Union Cabinet approves the ISRO proposal, will it take 10 years for ISRO to send an Indian into space?
It depends. We are working out the technical details, the elements that need to be developed. Preliminary estimates show that eight to 10 years could be the time-frame after approval.
Will it cost Rs.10,000 crores?It is a ballpark figure.After that, do we plan to send a man to the moon?
To go into orbit with a man and bring him back, we require a velocity increment of something like 11 km a second. If you want to go to the moon and come back [with him], it is 122 km a second. So the launch vehicles have to be more powerful, with a heavy lift capability that can provide this kind of velocity to the capsule. This needs to be addressed separately.
At what stage is the development of ISRO's re-usable launch vehicle?
We have not embarked on the development of the vehicle itself but a technology demonstration to study the hypersonic behaviour... of the vehicle and how to make the controls at a high mach regime. [One mach equals the speed of sound.] These experiments have been conceived and in two years from now, we will have a demonstrator flight. These inputs will go towards the design of a recoverable and reusable launch vehicle by 2010 or so.
Through a series of ground tests, you were able to achieve supersonic combustion and you held the flame for seven seconds when the velocity was Mach six (that is, six times the speed of sound).
There are very few countries that have demonstrated this capability, and perhaps we are the third in the series. The next step we are planning is a sounding rocket experiment. Sounding rockets are used to conduct experiments in the upper atmosphere. A sounding rocket will be modified to carry one of the air-breathing modules and that will be flown soon.
When?We have not fixed the date. It will take at least a year.
An article appeared in The Hindu recently that questioned ISRO's plans to send a man into space. It was sceptical of the benefits that would accrue from the mission. It also said it would go against Vikram Sarabhai's philosophy that space endeavour should bring benefits to the common man.
We want such inputs. Then only we can sharpen our thoughts on this process. I would say that it is a welcome analysis from a common man. We must keep in mind that humankind has progressed only because it has taken up challenges. If Columbus had not ventured [across the Atlantic], today's America would not have been there. Similarly, if we had not gone to Antarctica, we would not have known anything in-depth about oceans, life sciences and so on. Naturally, we will have an in-depth understanding of space [by sending a man to space]. For that, there is a price to pay.
If you take the space programme, the spin-offs are substantial. The technology spin-offs that will result from such a high-tech area can more than justify what you are spending.
India is emerging as an economic power. If you want to sustain this economic growth, scientific capacity has to match it. Perhaps the scientific and technical challenges are greater in space [exploration] than in another field. By investing in it [space exploration], we will contribute much more to our stature globally. A scientist commented at our meeting that the so-called cost for our manned mission is equivalent to building a 2,000 MWe power plant - Rs.5 crores for each MWe. So it is affordable.
When will you conduct the full-duration firing of the indigenous cryogenic stage for 720 seconds at Mahendragiri in Tamil Nadu?
We will do it in the last week of December. A cryogenic stage is one of the most difficult propulsion systems that can be developed. We have our own technology that is on a par with that of the advanced countries. We have mastered the technology and we have full confidence that we can reproduce it in flight. We have mastered the material technology in terms of stainless steel, copper, Kevlar composites, high-speed bearings, control components and so on. All these have come of age.
