The Geosynchronous Satellite Launch Vehicle Mark III, also referred to as the Launch Vehicle Mark 3, LVM3 or GSLV-III is a launch vehicle developed by the Indian Space Research Organisation (ISRO). ISRO successfully launched the Geosynchronous Satellite Launch Vehicle-Mark III on 5 June 2017 from the Satish Dhawan Space Centre, Andhra Pradesh.
It is intended to launch satellites into geostationary orbit and as a launcher for an Indian crewed space mission. The GSLV Mk. III has a higher payload capacity than the similarly named GSLV.
Originally ISRO's plans called for two launcher family, the PSLV for LEO and Polar launches and larger GSLV for payloads upto 2,000 kilograms (4,400 lb) to Geo-synchronous / GTO orbits. But due to the increase in size and complexity of communication and multipurpose satellites, expansion of ISROs mandate to include interplanetary exploration and an eventual crewed space mission, the need to develop a more powerful launcher became apparent. Development for the GSLV-III began in the early 2000s, with the first launch planned for 2009-2010. Several factors delayed the program, including the long development cycle and the unsuccessful launch GSLV D3 due to failure of the ISRO developed cryogenic upper stage which was a critical component of the launcher.. Even though the vehicle shares the name with ISRO's GSLV this is a completely new vehicle with minimal similarities to earlier ISRO launchers.
Two S200 solid motors, also known as Large Solid Boosters (LSB) attached to the Core stage powers the initial phase of the flight. Each booster has a diameter of 3.2 metres (10 ft), a length of 25 metres (82 ft), and carries 207 metric tons (456,000 lb) tonnes of propellant. S200 uses a HTPB based propellant and is the third largest solid booster used in any launch vehicle after the Space Shuttle and Ariane 5. Major components of the booster are the motor case, the propellent ignitor, the motor casing and the nose cone. The flex nozzle can be vectored using electro-hydraulic actuators and are used for vehicle control during the initial ascent phase. These boosters burn for 130 seconds and produce an average thrust of 3,578.2 kilonewtons (804,400 lbf) and a peak thrust of 5,150 kilonewtons (1,160,000 lbf) each.. The boosters separate from the core stage at T+149 seconds.
The second stage, designated L110, is a 21.26 metres (69.8 ft) tall and 4 metres (13 ft) diameter liquid-fueled stage carrying 110 metric tons (240,000 lb) of Unsymmetrical Dimethylhydrazine (UDMH) and Nitrogen Tetroxide (N2O4). The core is powered by two Vikas 2 engines. Vikas 2 engines are a derivative of the Viking II engines used aboard the European Ariane 1 to 4 launch vehicles. The L110 is the first Indian clustered liquidfueled engines. Each Vikas engine generates 766 kilonewtons (172,000 lbf)thrust in vacuum conditions, giving a total thrust of 1,532 kilonewtons (344,000 lbf). . The Vikas engines used in L110 uses regenerative cooling, providing improved weight and specific impulse compared to earlier versions. Each Vikas engine in the core can be individually gimbaled to allow vehicle control in pitch, yaw and roll. The L110 core stage ignites 114 seconds after liftoff and burns for 203 seconds.
The cryogenic upper stage (designated as C25) is powered by the CE-20 engine developed by ISRO. CE-20 is the first cryogenic engine developed by India which uses a Gas Generator compared to the Staged Combustion engines used in GSLV. It burns LOX and LH2 and produces 200 kN (45,000 lbf) of thrust. The C25 is 4 metres (13 ft) in diameter and 13.545 metres (44.44 ft) long, and contains 28 metric tons (62,000 lb) of propellant.
The payload fairing has a diameter of 5 metres (16 ft) and a payload volume of 110 cubic metres (3,900 cu ft).
First static test ST-01 of S-200 solid rocket booster was conducted on 24 January 2010. The booster fired for 130 seconds and generated a peak thrust of about 500 metric tons (1,100,000 lb). Nearly 600 ballistic and safety parameters were monitored during the test and indicated normal performance.
After experimental suborbital flight of LVM3X/CARE mission substantial modifications were made to S200 booster to increase its robustness. Propellant grain geometry of head end segment was changed to 13 lobed star configuration from 10 lobed slotted configuration and propellant load was reduced to 205 metric tons (452,000 lb). Third static test ST-03 took place on 14 June 2015 to validate these changes.
ISRO conducted the first static test of the L110 core stage at its Liquid Propulsion Systems Centre (LPSC) test facility at Mahendragiri, Tamil Nadu on 5 March 2010. Originally targeted for a full 200 second burn, the test was terminated at 150 seconds after a leakage in a control system was detected. A successful second test for the full duration, was conducted On 8 September 2010.
The first hot test of the C25 cryogenic stage was conducted at ISRO Propulsion Complex (IPRC) facility at Mahendragiri, Tamil Nadu on 25 January 2017. The stage was hot tested for a duration of 50 seconds demonstrating all stage operations. A longer duration test for the full in-flight duration of 640 seconds was completed on 17 February 2017. This test demonstrated the repeatability of the engine performance along with all its sub systems like thrust chamber, gas generator, turbo pumps and control components for the full duration. All the engine parameters were closely matching with the pre-test prediction.
The GSLV LVM-3 lifted off from the second launch pad, Sriharikota, at 9.30 am IST on 18 December 2014. The 630.5 metric tons (1,390,000 lb) launch vehicle stacking was as follows : a functional S200 solid propulsion stage, a functional L110 liquid propulsion stage, a non-functional dummy stage (in lieu of CE-20 cryogenic propulsion engine) and finally the 3.7-tonne CARE payload stage,to be tested for re-entry in a sub-orbital trajectory. Just over five minutes into the flight, the rocket ejected CARE at an altitude of 126 kilometres (78 mi). CARE then descended, controlled by its on-board motors. At an altitude of 80 kilometres (50 mi), the capsule began its ballistic re-entry into the atmosphere. During the test CARE’s heat shield was expected to experience and withstand a temperature of around 1,600 °C (2,910 °F). ISRO downloaded launch telemetry during the ballistic coasting phase prior to the radio black-out to avoid data loss in the event of a splash-down failure. At an altitude of around 15 kilometres (9.3 mi), the module’s apex cover separated and the parachutes were deployed. CARE splashed down in the Bay of Bengal near the Andaman and Nicobar Islands and was recovered successfully.  The Indian government has yet to give the go ahead for a crewed mission. 
After LVM3-X/CARE campaign few issues with launch vehicle were identified and following modifications were implemented prior to developmental flight 'D1'.
|Flight №||Date / time (UTC)||Rocket,
|Launch site||Payload||Payload mass||Orbit||User||Launch
|X||18 December 2014
|LVM3-X||Second||Crew Module Atmospheric Re-entry Experiment (CARE)||3,775 kg (8,322 lb)||Success|
|Sub-orbital development test flight with non-functional cryogenic stage|
|D1||5 June 2017
|Mk.III||Second||GSAT-19||3,136 kg (6,914 lb)||Success|
|First orbital test launch with a functional cryogenic stage|
|Date / time (UTC)||Rocket,
|D2; 3,500 kg (7,700 lb); Second orbital flight. |
|F01; 3,650 kg (8,050 lb); First operational flight of GSLV MK3.|
We will be checking the crew capsule for all parameters.