With the successful operational launch of GSLV F-05 rocket that hoisted the meteorological satellite INSAT-3DR into the geostationary transfer orbit (GTO), ISRO has entered into a new phase of self-reliance. Till now, PSLV (Polar Satellite Launch Vehicles), the trusted workhorse adorned the prestigious crown of ISRO with over consecutive 30 successful launches. PSLV could hoist satellites weighing few kilograms to less than 1400kg limiting ISRO’s capability of launching heavy satellites. PSLV are capable of carrying remote sensing satellites which are lighter and are placed in polar orbits. These satellites weigh from few hundred kilograms to about a tonne. Polar orbits are orbits in which satellites don’t move in tandem with the rotation of the earth and hence they are not suitable for communication. The cost efficiency and the reliability of PSLV has been established in the segment of the smaller satellites. India already boasts of 30 to 35% cheaper launches than other countries. Whereas Communication satellites are heavier, weigh 2 to 5 tons and need big boosters. GSLV series of vehicles are designed to hoist heavy satellites into the geosynchronous orbits 36,000km above the equator, where the satellite moves in tandem to earth’s rotation and hence service of satellite is available to the user all the time. GSLV (Geosynchronous Launch Vehicle) can carry satellites weighing over 1.5 tonnes to 4 tonnes. For heavier satellites of over 4 tonnes India employs Ariane-6 rocket of European Space Agency. Satellite launching services of foreign providers are very high. ISRO with three consecutive successful launches can now induct GSLVs for launch of heavy commercial satellites. Previous successful launches with the indigenous cryogenic engines were GSLV-D5 of January 2014 and GSLV-D6 August 2015 that launched GSAT-14 and GSAT-6 satellites into the designated orbits.
About the Launch & Satellite
The 49 meter- long, GSLV MkII, weighing 450 tons, powered by an indigenous cryogenic engine CE-7.5, lifted off from the second launch pad of Satish Dhawan Space Centre, Sriharikota delivered the satellite with remarkable precision. Launch was delayed by 40 minutes due to gas leak in a ground circuit. INSAT-3DR weighed 2211 kg of which 1225 kg is propellant. The propellant helps in satellite to fire up from the GTO to geostationary orbit and to maintain the satellite in the orbit slot during its life time. It is an advanced satellite with an imaging system, an atmospheric Sounder, Data-Relay Transponder & Satellite-aided search and Rescue Transponder. Imaging system with infrared and color camera can provide better night time pictures, images storms. Camera will take images every 26 minutes and its life span is 10 years. Sounder would collect data on humidity, temperature and ozone data from different layers of atmosphere. The satellite has solar arrays, generating power. This satellite will track storms and tropical cyclones, will relay data from remote weather stations and ocean buoys to weather forecast centers, precisely indicate distress signals from ships and planes, aiding in search and rescue operations. INSAT-3DR will supplement the services of INSAT-3D launched in 2013. INSAT-3DR now joins the conglomerate of meteorological satellites operated by ISRO- KALPANA, INSAT-3A and INSAT-3D.
Teething Problems with GSLV
India’s tryst with GSLV which began in 1986 was beset with many obstacles. When India announced its decision to start the project, several countries stepped forward to help and train personnel. Indeed, US and French companies had put forth their proposals. But India declined them because of high costs. Eventually India clinched an agreement with Russian company Glavkosmos by 1990 for supply of seven cryogenic engines of 7.5 tons thrust along with the transfer of cryogenic technology. But in 1993 irked by the Indo-Russian deal, US severely objected Russia selling cryogenic technology to India as this would be a violation under the Missile Technology Control regime (MTCR). As per MTCR guidelines, members established a “no undercut” policy means if a member denies sale of technology to another country, then the policy has to be strictly adhered by all other members. Further developed countries felt that their business interests would be severely threatened by India’s entry into the heavy satellite-launch business. Under pressure Russian company backed off from transferring technology, but supplied cryogenic engines and an additional mock-up engine. As a result, ISRO had to single-handedly sweat out to the technology which was zealously protected by all nations. Indigenous engines were eventually built at Liquid Propulsion Systems Centre, Thiruvananthapuram.
GSLV is a three stage launcher and ISRO has three variants- MkI, MkII, MkIII. All these variants have the solid-fuel first stage and a liquid fuel second stage powered by Vikas engine. The third stage of MkI uses the Russian cryogenic engines while the third stage CUS (Cryogenic Upper Stage) of MkII and MkIII have the indigenously developed engines CE-7.5 and CE-2- respectively. MkIII developmental flight is scheduled for launch by December 2016 is capable of carrying much heavier payloads. It will piggy-back GSAT-19 communication satellite. Once MkIII also establishes its reliability India will be become self-sufficient in terms of launching capacities. GSLV F-05 is an MkII variant capable of carrying payloads of around 2.5 tons. MkII has assured ISRO of its reliability during its two developmental flights. Unlike in developmental flight, during operational flight (the current launch) flight parameters (like altitude, relative velocity, time etc) or flight routes will not be tested.
Cryotechnology is incredibly difficult. In general, three types of rocket fuels are used- Solid, Liquid and gaseous. Solid fuels despite releasing more amount of energy than liquids are not preferred because of their high density. Liquid fuels flow and release more energy than gaseous fuels. It is established that when hydrogen gas burns in presence of oxygen, the combustion reaction generates 30% more thrust than other rocket fuels. In cryogenic technology, both hydrogen and oxygen are cooled to such a low temperature that they become liquids, occupy less space and start flowing. Hydrogen and Oxygen are liquefied under very low temperatures. Hydrogen is cooled to -253°C and Oxygen to -183°C and stored in pressurized chambers with extreme care as they are brittle, explosive in nature and can evaporate quickly. These propellants can’t be pumped into combustion chambers using normal pumps, special turbo pumps are to be employed. All operations must be condensation free. Presence of moisture can be disastrous for a launch. The magnitude of the extreme complexity is truly onerous.
So far ISRO conducted 10 launches with GSLV starting with GSLV-D1 (Mk1) in April 2001. Of which four launches have failed, one was a partial success and with the latest meticulous launch India seems to have tamed the “naughty boy” (GSLV fondly recalled by Indian scientists) GSLV. With this success, ISRO is now geared to launch second robotic mission to Moon Chandrayaan-2 in 2018 with a GSLV MkII variant. Moreover, with Space X’s Falcon 9 exploding ahead of its scheduled flight, global markets are experiencing the crunch of reliable launch vehicles for heavy satellites. GSLV F-05 successful launch boosted and substantially improved ISRO’s chances of making a mark in satellite launching services as a reliable player. ISRO’s reliability with MkIII would further establish its stature as trusted player facilitating its entry into the $300 billion global satellite-launching industry.