ISRO developing vehicle to launch small satellites

Interview with K. Sivan, Chairman, Indian Space Research Organisation.

Published : Aug 29, 2018 12:30 IST

 Dr. K. Sivan.

Dr. K. Sivan.

 IT has been a steady climb up the rungs of the Indian Space Research Organisation (ISRO) for the low-profile K. Sivan, who took over from A.S. Kiran Kumar as its Chairman on January 12. Sivan was earlier Director, Vikram Sarabhai Space Centre (VSSC), Thiruvananthapuram. He first came into the limelight on January 5, 2014, when ISRO’s Geosynchronous Satellite Launch Vehicle (GSLV-D5) flight, with an indigenously developed cryogenic engine, put the communication satellite GSAT-14 into a perfect orbit. He was the Mission Director for that crucial flight. 

A graduate in aeronautical engineering from the Madras Institute of Technology in 1980, Sivan took his M.E. in aerospace engineering from the Indian Institute of Science, Bengaluru, in 1982. He joined ISRO the same year in the Polar Satellite Launch Vehicle (PSLV) project and went on to contribute to its mission planning, design, integration and execution. He obtained his PhD in aerospace engineering from IIT Bombay in 2006. 

He was instrumental in establishing parallel computing and building a hypersonic wind tunnel facility at the VSSC. He came up with innovative strategies for sending India’s spacecraft to Mars by an uprated PSLV. 

Frontline  met Sivan for an interview in his office at the ISRO headquarters in Bengaluru in the context of ISRO’s major technology demonstration of a crew escape system, the first in a series of tests as part of India’s efforts to send astronauts into space (human spaceflight); the upcoming Chandrayaan-2 mission; and ISRO’s efforts to involve industries in building launch vehicles and satellites. Excerpts from the interview:

At what stage is the Chandrayaan-2 mission? Is the composite module, comprising the spacecraft, the lander and the rover, ready? It is going to be a highly complex mission.

As you said, Chandrayaan-2 is going to be a complex mission, and I will say that it is the most complex mission that ISRO has ever undertaken. This is the word that experts used when we called for a discussion on it. It is a very, very complex mission. In February or March, we had a review by eminent national experts. A point that came up for discussion was that the failure rates have been very high for spacecraft missions to the moon. Only 50 per cent have succeeded. Many of the missions failed during the landing phase, that is, the descent phase. The landing phase is new for Chandrayaan-2. We have already established the orbiter in Chandrayaan-1. The new thing is the rover. Of course, the rover has to come out of the lander, which is also new for us. We call it a complex mission because it is equivalent to three projects being done together [that is, the orbiter, the lander and the rover].

The second aspect is that when we talk about the launch vehicle, the Chandrayaan-2 mission is much more complex [than previous missions where we merely put a satellite into orbit]. After the orbiter is put into the lunar orbit, the lander has to separate and come down from the orbiter and land at a specified, predecided location on the moon. When there is such complexity, the national committee of experts asked for a lot of improvements, including redundancy and robustness in the system. When the lander lands, it should be a stable landing. It should not bump. So they suggested that we carry out a lot of simulation tests.

We worked on their suggestions and found out that the lander configuration of Chandrayaan-2 needed additional modifications. The other aspect is the additional tests we introduced. We have redesigned Chandrayaan-2. Work on the lander portion is going on.

Subsequent to the GSAT-6A mission, our own apex committee with former ISRO Chairman Dr K. Kasturirangan as the chairman suggested improvements in harnessing. [After the GSLV-F08 lifted off from Sriharikota on March 29, 2018, and put GSAT-6A into its initial orbit, communication from the satellite was lost on April 1 during its third orbit-raising operation. Power did not flow into the satellite’s electronic components. So no command could be given to the satellite.] 

The apex committee said, “Please check whether there is any failure mode” in Chandrayaan-2. We found that there was no failure mode. They suggested some improvements in the harnessing scheme, that is, the wiring. They suggested changes in the harnessing; that required changes in the orbiter also. So work is going on. We are now targeting the launch of Chandrayaan-2 by the end of this year. Because of these modifications, additional propellant margins are required in the original Chandrayaan-2 that had been planned. With all these changes, the mass of Chandrayaan-2 has increased from whatever we anticipated. When the mass increases, the project can still achieve the mission provided the launch vehicle can put the satellite into a higher orbit. The mass is 3.8 tonnes now.

The mass of the earlier composite module of Chandrayaan-2 was 3.2 tonnes. It has gone up to 3.8 tonnes now.

Earlier, we had thought of a 22,000 kilometre orbit [for 3.2 tonnes]. Now because of the increase in mass, the orbit has also increased. The orbit should be around 37,000 km.

It should now be 170 km x 37,000 km instead of 170 km x 22,000 km.

It is 170 km by 37,000 km. Since the mass has increased, the spacecraft has to be put into a higher orbit. Only then it is possible to reach the moon. Because of this, our old plan of launching Chandrayaan-2 by GSLV-MkII is not possible. We have changed Chandrayaan-2 to GSLV-MkIII for this reason.

GSLV-MkII is capable of putting a 2.8-tonne satellite into orbit. The original Chandrayaan-2 composite module weighed 3.2 tonnes and you were talking about building an enhanced GSLV-MkII.

You are right.

Umamaheswaran R., now Associate Scientific Secretary, ISRO, told me in October 2016 that GSLV-MkII can put 3.2 tonnes into an initial orbit of 180 km by 20,000 km.

Yes. We enhanced the GSLV-MkII with high thrust engines and so on. With the enhancement, the number is 2.7 tonnes into GTO [geostationary transfer orbit]. Now, 3.2 tonnes has become 3.8 tonnes. And 22,000 km has become 37,000 km. This combination cannot be launched by GSLV-MkII. 

What are the challenges that ISRO faced in developing the lander after Russia, which was to build it, backed out? It has a throttleable engine for soft landing on the moon. The lander should do in-place navigation. Although you have defined the place where the lander should land on the moon, it should be able to change its mind if there are hazards.

Considering the mass of the lander, the thrust level should be very large, around 3.2 kilonewtons or 4 kilonewtons. Making a throttleable engine of 3 kilonewtons or 4 kilonewtons is a totally new development for us. But we wanted to make use of available technologies. We have a LAM [liquid apogee motor] with a 400 newton thruster, and we have been using it on our satellites. We enhanced it to 800 newtons. It was not a major, new design change. 

[The propulsion system aboard the lander will comprise a cluster of 4x800 N throttleable engines and eight numbers of 50 N control thrusters. This configuration will lead to considerable saving in the weight of propellants, enabling more scientific instruments to be carried on board.]

Another challenge is that we are landing on the moon for the first time. When we are doing the landing, the sensors should be perfect. Any error in the sensors may lead to the end-phase—we will not know whether we have reached the lunar ground or if we are above it. To get clarity on this, we will be, for the first time, attempting to land the lander into an in-between orbit: orbiter to lander, and then landing. We will first make the lander to go into an orbit between the orbiter’s orbit and the landing. It will be an orbit with an apolune [farthest point from the moon] equal to 22,000 km and perilune [closest point to the moon] of 100 km. 

After checking the lander’s performance and confirming whether the orbit is correct, we will start the landing manoeuvre. So it will be a step-by-step, cautious procedure from the moon orbit to landing. In the process, we have the time to check the performance of the systems. That way we can ensure that everything is done as per plan, and subsequently make sure that we are right and only then continue. That way, we gain confidence.

The third aspect is that we have done simulation tests on bringing the real electronics in the loop.

Have you done a lot of simulation tests with the lander?

We have done a lot. We are going to do a lot more wherein the lander will have all the electronics and software. We will be simulating the actual phenomena during landing at Mahendragiri in Tamil Nadu. That way, the tests we are doing will be close to reality. We expect that with these points we will have the confidence to go ahead.

What are the experiments the lander and the rover will do?

The lander will insert a probe, a kind of in situ  measurement. The rover will do in situ  measurements by moving about, but the lander will do it by staying in one place. In the lander a system will come out, a probe will go inside the lunar soil, study the soil profile, and so on. It will do a good amount of tests. It will test the lunar soil characteristics.

Prime Minister Narendra Modi announced in his Independence Day speech that India would send astronauts, including a woman, to space in 2022 as part of ISRO’s human space flight (HSF) programme. Do you think you can meet this deadline, given the project’s vast complexity?

This is an excellent gift from the Prime Minister to the nation. This project is going to enhance the level of science and technology in the country. It will inspire our youth. Not only ISRO but a lot of other organisations, including industries, academia and research institutes, will participate in the programme. That way it will be a national project and bring dividends to science and technology. We are happy about the Prime Minister’s announcement. The schedule is very tight, but we will meet it.

How many flights of GSLV-MkIII should you do before it is declared a man-rated vehicle, capable of taking astronauts to space?

We will use GSLV-MkIII. We will make it a man-rated vehicle. But its payload-carrying capacity will come down if you make it a man-rated vehicle. This vehicle is capable of carrying 10 tonnes of payload into low-earth orbit. By man-rating it, we will meet the requirements of our human space flight programme. It demands seven tonnes of payload [that is, the crew capsule will weigh seven tonnes]. Mk-III will be able to meet this payload demand. We chose MkIII because it is a simple vehicle. It has fewer number of stages. We will launch the vehicle 10 to 15 times before we use it for the HSF.

Will you send three astronauts into space in India’s first manned mission?


Will it include a woman?

Probably. Nowadays, women are stronger than men.

What are the technologies that you have to work on for the mission?

We have developed the crew module. We have to do the Pad Abort Test [PAT] at different times of the day. We have to build the environment-control and life-support systems for the crew. We have to build the ergonomics of the entire system. The interface between man and the instrumentation should be done. Our non-technical activities will include those relating to the Indian Air Force and the Coast Guard. The selection and training of astronauts should be done immediately. The schedule is very tight, but we will do it.

With regard to the HSF programme, the very first step you took was the Space Capsule Recovery Experiment (SRE) where you brought back a satellite to earth in January 2007. It re-entered the earth’s atmosphere and you recovered it from the sea near Chennai. Then you did CARE—Crew Module Atmospheric Re-entry Experiment—where you put a 3.75-tonne unmanned crew module into a sub-orbit and made it splash down in the Bay of Bengal in December 2014. You did a PAT on July 5 to demonstrate the safe recovery of the crew module in case of any exigency on the launch pad. With the help of parachutes, the crew module splashed down in the sea. I have seen space suits that VSSC has developed for astronauts. 

We do the technology development well in advance not only for the HSF, but for any technology. We developed the cryogenic stage and demonstrated it in 2014. When I joined ISRO in 1982, close to my room, there was a group working one cryogenic development. In ISRO, we always work on development of technologies. All the technology developments we do in ISRO are linked to a project. Before the activity fructifies into a project, technology development will happen.

One such technology development is the PAT. This particular crew escape system requires a complex motor, with the unique characteristics of giving the highest thrust within the shortest time. So its nozzle geometry will be different, It is like a reverse motor. We have to make use of aerodynamics to tilt the vehicle to 1800°. Only then, when the module is separated, it will be turned on by its own aerodynamics. Then, there will be favourable conditions for the parachutes to open and the module will be brought back to the earth. This is the mission profile. This profile during the mission, that is, the production of the entire system—the crew escape module, then the aerodynamic module, the realisation of the electronic components—we did in a fantastic way and they performed very well during the PAT.

Along with these functional tests, we did five stage experiments, which we have to do in space. So we did the qualification of the crew escape system and were able to demonstrate five additional, new products on that day. We got a test bed to carry out the tests.

What were the five new tests?

New technologies. One experiment is wireless communication. We demonstrated a wireless instrument system during the PAT.

Then we demonstrated a digital telemetry transmitter. Right now, we use the analog system. It is bulky and consumes a lot of power. The digital system will be compact and power consumption will be lower. The third technology was the Ka-band altimeter. This will be used in Chandrayaan-2 when the lander is coming down.

Another technology we demonstrated was the MSS [Mobile Satellite Services] via GSAT-6. Right now, any data we want to get from the cloud is acquired through ground stations. They track a satellite or an aircraft. We need ground stations to track the entire flight trajectory, wherever the vehicle is going. If you have a long trajectory, we need a ground station to acquire the data. But in the MSS link via GSAT-6, the data will go from the flight system to the GSAT-6 satellite. The GSAT-6 can reflect the data and relay it to a ground station. So we don’t have to plan all the ground stations.

The fifth experiment we did was the NAVIC System. NAVICS is now working for slow-moving systems, static systems. We are now releasing it for moving systems, [to see] whether it will work for highly accurate vehicles. These vehicles will have 100 G [100 times the gravitational force experienced in normal conditions]. NAVICS will function in this condition also.

You have been passionate about ISRO-industry collaboration. You have talked about how Indian industry can build and integrate a launch vehicle by 2020. In this context, you have been talking about a mini-PSLV.

We are now in the process of developing a launch vehicle for small satellites. That is planned to be fully realised by the industry.

Is this a mini-PSLV?

It is an SSLV, or Small Satellite Launch Vehicle. We are planning that to be fully realised by the industry. Right now, its development phase is part of ISRO. After development is over, it will be given to industry for production.

What are the dimensions of this vehicle?

It is a small vehicle. I am not able to recollect the dimensions of the vehicle. It will weigh less than 100 tonnes.

What will be the weight of the satellite that it can put into orbit?

It can put a 500-kg satellite into a 500-km orbit. 

Is there a lot of demand for putting small satellites into orbit?

Basically, this [SSLV] is to cater to the market for small satellites. This vehicle will be cost-effective. It will take the lowest integration time, about 72 hours. The launch operations will be carried out by three or four people only.

From the Mission Control Centre?

No Mission Control Centre. Somewhere some PC [personal computer] will be there. The PC can even be in the guest house!

So a 100-tonne rocket can be launched with the help of a PC in a guest house?

Not because of the size of the rocket, but because we wanted to introduce an innovation in this type of vehicle. We are adding new technology. The vehicle will be more and more autonomous.

What are the industries that will be realising this vehicle—L&T, MTAR?

We had a brief discussion with L&T. They wanted to produce it. Many people are there for this project. Our Antrix [the marketing company of the Department of Space] is working on that.

What are the rocket motors that L&T will produce in its Coimbatore plant? 

They will be producing solid motors. There, too, we are talking of small motors. We are going to industry for the production of PSLVs.

Out of the government’s recent approval of Rs.10,400 crore for 30 PSLVs and 10 GSLV-MkIIIs, nearly 85 per cent, Rs.9,000 crore, will be with industry only. It will be a big bonus to industry. It can plan now. Industry has to come up with new ideas as to how it will meet the large demand for spacecraft as well as launch vehicles.

Industry is already playing an important role in supplying components for building ISRO’s satellites. When will industry be able to build a satellite on its own?

When we are talking about launch vehicles, whether it is a PSLV or satellites—100 per cent building them—industry can do it only when the entire technology is transferred to it with proper documentation. Then industry can produce them.

In the recent satellite launches, industry did make some important contributions.

In all the launches, in the launch vehicles, industry is doing its work. We are not doing the work. Industry is doing the work and we are getting the name. In every launch, in every vehicle of ISRO, 85 per cent of the cost of the vehicle is lying with industry, mainly on materials and the manufacturing cost. These materials form 16 per cent of the total weight of the vehicle. Sixteen per cent of the items of the vehicle account for 85 per cent of the cost of the vehicle. This 85 per cent is lying with industry.

A unique system in the VSSC is that whenever we add extra manpower, we convert it into a work package and that work package is given to a vendor. After he finishes the work, he gets the money and goes away. A similar approach is being adopted.

The satellite is not made in the industry. It is made by the industry. It is made by industrial labour.

TeamIndus could not mobilise enough cash to send a rover to the moon using ISRO’s PSLV. This despite big Indian industrialists being associated with TeamIndus. So are you really confident that Indian industry can do it, that is, build launch vehicles and satellites?

I do not want to talk about TeamIndus. I am not fully involved in that. But I strongly believe that our industry can do it. Also, every component is made now by the industry. As much as 85 per cent of the package is made in the industry. These people are now fabricating rocket components. After fabricating them, they give it to us as vendors. We tell them, “Don’t be a vendor. We want to make you a partner.” It is like somebody is employed in a person’s house. Suddenly, the house owner’s son is marrying the employee’s daughter. The employer becomes the father-in-law.

Can you give me the list of industries that are making important contributions to ISRO’s launch vehicles and satellites? What are the components they manufacture? 

We have HAL. It is making all the aluminium light alloy structures, core-based shroud, propellant tanks for the engines, payload fairings, inter-stage structures, and so on. Godrej is fabricating the engines and its components. Then we have L&T, which is doing the solid motor casings. Walchandnagar Industries is also producing motor casings. Another big fish, MTAR, is producing the control components for the engines. MIDHANI is producing metallic materials like maraging steel. Bharat Forge is giving some forgings. Bay Forge, near Chennai, is also doing the forgings. 

Along with the big fish, there are medium industries such as Sri Venkateswara Mechanical, Electrical and Engineering Industry in Hyderabad. It is supplying us strap-on motor casings. Then there is KELTRON.

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