LVM3

ISRO initially planned two launcher families, the Polar Satellite Launch Vehicle for low Earth orbit and polar launches and the larger Geosynchronous Satellite Launch Vehicle for payloads to geostationary transfer orbit (GTO). The vehicle was reconceptualized as a more powerful launcher as the ISRO mandate changed. This increase in size allowed the launch of heavier communication and multipurpose satellites, human-rating to launch crewed missions, and future interplanetary exploration.^[30] Development of the LVM3 began in the early 2000s, with the first launch planned for 2009–2010.^[31][32][33] The unsuccessful launch of GSLV D3, due to failure in the cryogenic upper stage,^[33] delayed the LVM3 development program.^[34][35] The LVM3, while sharing a name with the GSLV, features different systems and components.

To manufacture the LVM3 in public–private partnership (PPP) mode, ISRO and NewSpace India Limited (NSIL) have started working on the project. To investigate possible PPP partnership opportunities for LVM3 production through the Indian private sector, NSIL has hired IIFCL Projects Limited (IPL).^[36] On Friday 10th May 2024, NSIL released a request for qualification (RFQ), inviting responses from private partners for the large-scale production of LVM-3.^[37][38][39] Plans call for a 14-year partnership between ISRO and the chosen commercial entity. The private partner is expected to be able to produce four to six LMV3 rockets annually over the following twelve years, with the first two years serving as the "development phase" for the transfer of technology and know-how.^[40]

Specifications

First stage- 2 x S200 Strap-on

Second stage- L110

Third stage- C25 CUS

S200 solid boosters

The first stage consists of two S200 solid motors, also known as Large Solid Boosters (LSB) attached to the core stage. Each booster is 3.2 metres (10 ft) wide, 25 metres (82 ft) long, and carries 207 tonnes (456,000 lb) of hydroxyl-terminated polybutadiene (HTPB) based propellant in three segments with casings made out of M250 maraging steel. The head-end segment contains 27,100 kg of propellant, the middle segment contains 97,380 kg and the nozzle-end segment is loaded with 82,210 kg of propellants. It is the largest solid-fuel booster after the SLS SRBs, the Space Shuttle SRBs and the Ariane 5 SRBs. The flex nozzles can be vectored up to ±8° by electro-hydraulic actuators with a capacity of 294 kilonewtons (66,000 lb_f) using hydro-pneumatic pistons operating in blow-down mode by high pressure oil and nitrogen. The are used for vehicle control during the initial ascent phase.^[41][42][43] Hydraulic fluid for operating these actuators is stored in an externally mounted cylindrical tank at the base of each booster.^[44] These boosters burn for 130 seconds and produce an average thrust of 3,578.2 kilonewtons (804,400 lb_f) and a peak thrust of 5,150 kilonewtons (1,160,000 lb_f) each. The simultaneous separation from core stage occurs at T+149 seconds in a normal flight and is initiated using pyrotechnic separation devices and six small solid-fueled jettison motors located in the nose and aft segments of the boosters.^[42][9]

The first static fire test of the S200 solid rocket booster, ST-01, was conducted on 24 January 2010.^[9] The booster fired for 130 seconds and had nominal performance throughout the burn. It generated a peak thrust of about 4,900 kN (1,100,000 lbf).^[45][10] A second static fire test, ST-02, was conducted on 4 September 2011. The booster fired for 140 seconds and again had nominal performance through the test.^[46] A third test, ST-03, was conducted on 14 June 2015 to validate the changes from the sub-orbital test flight data.^[47][48]

L110 liquid core stage

The second stage, designated L110, is a liquid-fueled stage that is 21 metres (69 ft) tall and 4 metres (13 ft) wide, and contains 110 metric tons (240,000 lb) of unsymmetrical dimethylhydrazine (UDMH) and nitrogen tetroxide (N₂O₄). It is powered by two Vikas 2 engines, each generating 766 kilonewtons (172,000 lb_f) thrust, giving a total thrust of 1,532 kilonewtons (344,000 lb_f).^[13][14] The L110 is the first clustered liquid-fueled engine designed in India. The Vikas engines uses regenerative cooling, providing improved weight and specific impulse compared to earlier Indian rockets.^[42][49] Each Vikas engine can be individually gimbaled to control vehicle pitch, yaw and roll control. The L110 core stage ignites 114 seconds after liftoff and burns for 203 seconds.^[42][14] Since the L110 stage is air-lit, its engines need shielding during flight from the exhaust of the operating S200 boosters and reverse flow of gases by a 'nozzle closure system' which gets jettisoned prior to L110 ignition.^[50]

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. The test was planned to last 200 seconds, but was terminated at 150 seconds after a leakage in a control system was detected.^[51] A second static fire test for the full duration was conducted on 8 September 2010.^[52]

C25 cryogenic upper stage

The cryogenic upper stage, designated C25, is 4 metres (13 ft) in diameter and 13.5 metres (44 ft) long, and contains 28 metric tons (62,000 lb) of propellant LOX and LH₂, pressurized by helium stored in submerged bottles.^[49][53] It is powered by a single CE-20 engine, producing 200 kN (45,000 lb_f) of thrust. CE-20 is the first cryogenic engine developed by India which uses a gas generator, as compared to the staged combustion engines used in GSLV.^[54] In LVM3-M3 mission, a new white coloured C25 stage was introduced which has more environmental-friendly manufacturing processes, better insulation properties and the use of lightweight materials.^[55] The stage also houses the flight computers and Redundant Strap Down Inertial Navigation System of the launch vehicle in its equipment bay. The digital control system of the launcher uses closed-loop guidance throughout the flight to ensure accurate injections of satellites into the target orbit. Communications system of the launch vehicle consisting of an S-Band system for telemetry downlink and a C-Band transponder that allows radar tracking and preliminary orbit determination are also mounted on the C25. The communications link is also used for range safety and flight termination that uses a dedicated system that is located on all stages of the vehicle and features separate avionics.^[42]

The first static fire test of the C25 cryogenic stage was conducted on 25 January 2017 at the ISRO Propulsion Complex (IPRC) facility at Mahendragiri, Tamil Nadu. The stage fired for a duration of 50 seconds and performed nominally.^[56] A second static fire test for the full in-flight duration of 640 seconds was completed on 17 February 2017.^[57] This test demonstrated consistency in engine performance along with its sub-systems, including the thrust chamber, gas generator, turbopumps and control components for the full duration.^[57]

Payload fairing

The CFRP composite payload fairing has a diameter of 5 metres (16 ft), a height of 10.75 metres (35.3 ft) and a payload volume of 110 cubic metres (3,900 cu ft).^[8] It is manufactured by Coimbatore-based LMW Advanced Technology Centre.^[58] After the first flight of the rocket with CARE module, the payload fairing was modified to an ogive shape, and the S200 booster nose cones and inter-tank structure were redesigned to have better aerodynamic performance.^[59] The vehicle features a large fairing with a five-meter diameter to provide sufficient space even to large satellites and spacecraft. Separation of fairing in a nominal flight scenario occurs at approximately T+253 seconds and is accomplished by a linear piston cylinder separation and jettisoning mechanism (zip cord) spanning full length of PLF which is pyrotechnically initiated. The gas pressure generated by the zip cord expands a rubber below that pushes the piston and cylinder apart and thereby pushing the payload fairing halves laterally away from the launcher. The fairing is made of Aluminum alloy featuring acoustic absorption blankets.^[42]

Human-rating certification

While the LVM3 is being human rated for Gaganyaan project, the rocket was always designed with potential human spaceflight applications in consideration. The maximum acceleration during ascent phase of flight was limited to 4 Gs for crew comfort and a 5-metre (16 ft) diameter payload fairing was used to be able to accommodate large modules like space station segments.^[60]

Furthermore, a number of changes to make safety-critical subsystems reliable are planned for lower operating margins, redundancy, stringent qualification requirements, revaluation, and strengthening of components.^[61] Avionics improvement will incorporate a Quad-redundant Navigation and Guidance Computer (NGC), Dual chain Telemetry & Telecommand Processor (TTCP) and an Integrated Health Monitoring System (LVHM). The launch vehicle will have the High Thrust Vikas engines (HTVE) of L110 core stage operating at a chamber pressure of 58.5 bar instead of 62 bar. Human rated S200 (HS200) boosters will operate at chamber pressure of 55.5 bar instead of 58.8 bar and its segment joints will have three O-rings each. Electro mechanical actuators and digital stage controllers will be employed in HS200, L110 and C25 stages.^[62]

Mating with semi-cryogenic stage

The L110 core stage in the LVM3 is planned to be replaced by the SC120, a kerolox stage powered by the SCE-200 engine^[63] to increase its payload capacity to 7.5 metric tons (17,000 lb) to geostationary transfer orbit (GTO).^[64] The SCE-200 uses kerosene instead of unsymmetrical dimethylhydrazine (UDMH) as fuel and has a thrust of around 200 tonnes. Four such engines can be clustered in a rocket without strap on boosters to deliver up to 10 tonnes (22,000 lb) to GTO.^[65] The first propellant tank for the SC120 was delivered in October 2021 by HAL.^[66]

The SC120 powered version of LVM3 will not be used for the crewed mission of the Gaganyaan spacecraft.^[67][68] In September 2019, in an interview by AstrotalkUK, S. Somanath, director of Vikram Sarabhai Space Centre claimed that the SCE-200 engine was ready to begin testing. As per an agreement between India and Ukraine signed in 2005, Ukraine was expected to test components of the SCE-200 engine, so an upgraded version of the LVM3 was not expected before 2022.^[69] The SCE-200 engine is reported to be based on the Ukrainian RD-810, which itself is proposed for use on the Mayak family of launch vehicles.^[70]

Induction of upgraded cryogenic stage

The C25 stage with nearly 25 t (55,000 lb) propellant load will be replaced by the C32, with a higher propellant load of 32 t (71,000 lb). The C32 stage will be re-startable and with uprated CE-20 engine.^[71] Total mass of avionics will be brought down by using miniaturised components.^[72] On 30 November 2020, Hindustan Aeronautics Limited delivered an aluminium alloy based cryogenic tank to ISRO. The tank has a capacity of 5,755 kg (12,688 lb) of fuel, and a volume of 89 m³ (3,100 cu ft).^[73][74]

On 9 November 2022, CE-20 cryogenic engine of upper stage was tested with an uprated thrust regime of 21.8 tonnes in November 2022. Along a suitable stage with additional propellant loading this could increase payload capacity of LVM3 to GTO by up to 450 kg (990 lb).^[75] On 23 December 2022, CE-20 engine E9 was hot tested for 650 second duration. For the first 40 seconds of test, the engine was operated at 20.2 tonne thrust level, after this engine was operated at 20 tonne off-nominal zones and then for 435 seconds it was operated at 22.2 tonne thrust level. With this test, the 'E9' engine has been qualified for induction in flight.^[76]

Flight X

The maiden flight of the LVM3 lifted off from the Second Launch Pad at the Satish Dhawan Space Center on 18 December 2014 at 04:00 UTC.^[77] The test had functional boosters, a core stage but carried dummy upper stage whose LOX and LH₂ tanks were filled with LN₂ and GN₂ respectively for simulating weight. It also carried the Crew Module Atmospheric Re-entry Experiment (CARE) that was tested on re-entry.^[78]

Just over five minutes into the flight, the rocket ejected CARE at an altitude of 126 kilometres (78 mi), which then descended, controlled by its onboard reaction control system. During the test, CARE's heat shield experienced a peak temperature of around 1,000 °C (1,830 °F). ISRO downlinked launch telemetry during the ballistic coasting phase until the radio black-out to avoid data loss in the event of a 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.^{[79][80][81][82]}

Chandrayaan

Following the failure of Phobos-Grunt mission of Roscosmos, it resulted in a complete review of technical aspects connected with the spacecraft, which were also slotted to be used in the proposed Russian lander for Chandrayaan-2. This delayed the lander from Russia and eventually Roscosmos declared its inability to meet up with the revised time of 2015 for its launch on board an uprated GSLV rocket along with an Indian orbiter and rover. ISRO cancelled the Russian agreement and decided to go alone with its project with marginal changes.^[83][84]

On 22 July 2019, the LVM3 M1 (GSLV Mk.III M1) rocket lifted off with 3850 kg Chandrayaan-2 Orbiter-Lander composite and successfully injected it into a parking orbit of 169.7 x 45,475 km. This marked the first operational flight of LVM3 after two developmental flights.^[85] The apogee of the earth parking orbit is about 6,000 km more than originally envisaged and thereby eliminated one of the seven earth-bound orbit raising manoeuvres. It was attributed to a 15 percentage increase in rocket performance.^[86][87] On 14 July 2023, the LVM3 M4 rocket successfully injected the 3900 kg Chandrayaan-3 composite to a parking orbit of 170 x 36,500 km.^[88] On 15 November 2023, the Cryogenic Upper Stage (C25) of the LVM3 M4 (NORAD ID: 57321) made an uncontrolled re-entry into the Earth's atmosphere around 9:12 UTC. The impact point is predicted over the North Pacific Ocean and the final ground track did not pass over India.^[89][90][91]

OneWeb

On 21 March 2022, OneWeb announced that it had signed a launch agreement with United States launch provider SpaceX to launch the remaining 1st generation satellites on Falcon 9 rockets, with the first launch expected no earlier than summer 2022.^[92][93] On 20 April 2022 OneWeb announced a similar deal with NewSpace India Limited, the commercial arm of the Indian Space Research Organisation.^[94] OneWeb satellites were deployed by LVM3 both on 22 October 2022 and 26 March 2023^[95] using a lightly modified version of the satellite dispenser previously used on Soyuz.^[96][97]

The first batch of 36 OneWeb Gen-1 satellites weighing a total of 5796 kg was launched onboard LVM3 M2 rocket codenamed OneWeb India-1 Mission on 22 October 2022 and the satellites were injected to a low earth orbit of 601 km altitude and 87.4° inclination on a sequential basis. This constituted the first commercial mission and the first multi-satellite mission to low earth orbit of the rocket, marking its entry to global commercial launch service market. The separation of satellites involved a unique maneuver of the cryogenic stage to undergo several re-orientation and velocity additions covering 9 phases spanning 75 minutes.^[98][99] On 26 March 2023, codenamed OneWeb India-2 Mission, the second batch of 36 satellites was launched onboard LVM3 M3 and injected to an altitude of 450 km with same inclination. The launch featured a white cryogenic stage which takes into account environmental-friendly manufacturing processes, better insulation properties and the use of lightweight materials.^[100][55]

LVM3 currently have accumulated a total of 7 launches as of 19 July 2023^[update]. Of these, all 7 were successful. The cumulative success rate is 100%.

Decade-wise summary of LVM3 launches

• 
  D1/GSAT-19
• 
  D2/GSAT-29
• 
  M1/Chandrayaan-2
• 
  M2/OneWeb
• 
  M4/Chandrayaan-3

• Gaganyaan
• List of Indian satellites
• Comparison of orbital launch systems
• Comparison of orbital launchers families

Wikimedia Commons has media related to Launch Vehicle Mark III.

• Bharat-Rakshak GSLV-III information
• New Scientist article including GSLV-III diagram