CE-20
First Indian cryogenic engine with gas-generator cycle.
The CE-20 is a cryogenic rocket engine built by the Liquid Propulsion Systems Centre (LPSC), part of ISRO, to drive the upper stage of the LVM3 launch vehicle. It is India’s first cryogenic engine to use a gas-generator cycle and is currently the most powerful upper-stage cryogenic engine in active service. The engine is qualified at three thrust levels: 19 tonnes for routine satellite missions, 20 tonnes for the Gaganyaan program, and an upgraded 22 tonnes for future launches.
The engine delivers a nominal thrust of 200 kN, with an operating range between 180 kN and 220 kN that can be set to any fixed value within those limits. Its combustion chamber burns liquid hydrogen and liquid oxygen at a pressure of 6 MPa with a mixture ratio of 5.05. The CE-20 has a thrust-to-weight ratio of 34.7 and a specific impulse of 442 seconds (4.33 km/s) in vacuum.
Development and testing of the CE-20 began with a 635-second hot test on 28 April 2015 at IPRC, Mahendragiri, following two cold start tests and four short hot tests. On 16 July 2015, the first developmental engine, E1, completed an 800-second endurance test with a closed-loop Mixture Ratio Controller (MRC), lasting about 25% longer than a flight burn. A 5.7-second hot test on 10 August 2015 demonstrated ignition under flight-like tank pressure. The second developmental engine, E2, was tested for 640 seconds on 19 February 2016. On 3 December 2016, the third engine, E3, passed a 25-second flight acceptance test in high-altitude conditions and flew on the first developmental LVM3 flight on 5 June 2017. On 25 January 2017, engine E2, integrated with the C25 development stage, was tested for 50 seconds, followed by a 640-second test on 17 February 2017. On 11 October 2018, engine E6 completed a 25-second high-altitude flight acceptance test for the Chandrayaan-2 mission. On 16 December 2021, engine E9 underwent two 3.2-second ignition trials and a 50-second hot test to verify repeatable ignition and stable combustion. On 12 January 2022, E9 completed a 720-second qualification test for the Gaganyaan program. On 29 October 2022, engine E11 passed a 25-second flight acceptance test for the LVM3 M3 mission. On 9 November 2022, E9 was tested for 70 seconds, operating at about 20 tonnes thrust for the first 40 seconds and then switching to an uprated 21.8 tonnes.
Quick Facts
- Country Of Origin
- India
- First Date
- 5 June 2017
- Designer
- LPSC, ISRO
- Manufacturer
- Hindustan Aeronautics Limited
- Purpose
- Upper stage booster
- Oxidiser
- LOX
- Fuel
- LH2
- Mixture Ratio
- 5.05
- Cycle
- Gas Generator
- Combustion Chamber
- 1
- Nozzle Ratio
- 100
- Thrust(Vac)
- 186.36 kN
Facts from the source article.
Lore & Background
The CE-20 engine was developed by the Liquid Propulsion Systems Centre (LPSC), a subsidiary of ISRO, to power the upper stage of the LVM3. It is the first Indian cryogenic engine to feature a gas-generator cycle and is the most powerful upper stage cryogenic engine in operational service. The engine produces a nominal thrust of 200 kN, with an operating range between 180 kN and 220 kN, and burns liquid hydrogen and liquid oxygen at 6 MPa with a 5.05 engine mixture ratio.
Development and testing of the CE-20 began with a 635-second hot test on 28 April 2015 at IPRC, Mahendragiri. Subsequent tests included endurance runs of 800 seconds on the first developmental engine 'E1' on 16 July 2015, and a 640-second test on the second developmental engine 'E2' on 19 February 2016. The third developmental engine 'E3' completed a flight acceptance test on 3 December 2016 and flew on the first developmental flight 'D1' of the GSLV Mk-III on 5 June 2017.
Further testing qualified the engine for various thrust levels: 19 tonnes for ongoing satellite missions, 20 tonnes for the Gaganyaan program, and an upgraded 22 tonnes for future launches such as the Bharatiya Antariksh Station's BAS-01 Base Module. On 9 November 2022, engine E9 operated at approximately 20 tonnes for 40 seconds then switched to 21.8 tonnes for 30 seconds, introducing a Thrust Control Valve and 3D-printed turbine components. On 23 December 2022, E9 operated at 22.2 tonnes for 435 seconds, qualifying it for flight. The engine was human-rated for Gaganyaan after a series of tests culminating on 13 February 2024.
Reader's Guide
The CE-20 engine represents a significant milestone in Indian cryogenic propulsion, being the first Indian cryogenic engine to use a gas-generator cycle. Its development enabled the LVM3 to become operational, supporting critical missions including Chandrayaan-2, Chandrayaan-3, and the upcoming Gaganyaan human spaceflight program. The engine's ability to operate at multiple thrust levels—19 tonnes for satellite missions, 20 tonnes for Gaganyaan, and 22 tonnes for future launches—demonstrates its versatility and adaptability.
Testing achievements include a cumulative burn duration of 3370 seconds across twelve hot tests on engine E9, and qualification for 22-tonne thrust operation through multiple tests on engine E13 in 2023. The engine also demonstrated bootstrap-mode startup under vacuum on 7 November 2025, a world first for a gas-generator cycle engine, enabling potential in-orbit restart capabilities. Upgraded versions with a nozzle protection system and high-area nozzle ratio of 100 were tested in 2024-2026, intended for future LVM3 missions with an uprated C32 stage to increase payload capacity. The CE-20's legacy lies in its role as the most powerful upper stage cryogenic engine in operational service and its contribution to India's expanding space capabilities.
Did You Know?
- On 7 November 2025, a bootstrap-mode start test was conducted under vacuum, the first time a gas-generator cycle engine was tested in bootstrap mode in the world.
- The CE-20 engine was human-rated for the Gaganyaan programme on 13 February 2024 after a series of ground qualification tests.
Frequently Asked Questions
What is the CE-20?
The CE-20 is a cryogenic rocket engine developed by ISRO's Liquid Propulsion Systems Centre to serve as the upper-stage motor for the LVM3 launch vehicle. It currently holds the title of the most powerful upper-stage cryogenic engine in active service.
Who designed and built the CE-20?
The engine was developed by the Liquid Propulsion Systems Centre (LPSC), a facility operating under India's space agency ISRO. It stands as a fully homegrown Indian achievement in high-performance rocket propulsion.
What makes the CE-20 technically unique?
It is the first Indian cryogenic engine to employ a gas-generator cycle, a design choice that streamlines the turbopump feed system relative to earlier expander-cycle engines. In vacuum it achieves a specific impulse of 442 seconds and a thrust-to-weight ratio of 34.7.
What thrust levels can the CE-20 deliver?
The engine is qualified at three settings: 19 tonnes for routine satellite launches, 20 tonnes for the Gaganyaan crewed-flight program, and an upgraded 22 tonnes reserved for future heavy missions. Its adjustable operating window spans 180 kN to 220 kN around a 200 kN nominal output.
Why is the CE-20 a milestone for Indian spaceflight?
By powering the LVM3 upper stage, it gives India the capability to place heavier payloads into high orbits and to support crewed missions such as Gaganyaan. Its gas-generator architecture also sets a foundation for more reliable, scalable cryogenic propulsion in upcoming launch vehicles.
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