GSLV-D5 India's first Indigenous Cryogenic Stage GSAT-14

GSLV-D5 with Indigenous Cryogenic Stage successfully launches GSAT-14 from SDSC SHAR.

GSLV-D5 is the eighth flight of India’s Geosynchronous Satellite Launch Vehicle (GSLV). It is also the fourth developmental flight of GSLV. During this flight, the indigenously developed Cryogenic Upper Stage (CUS) will be flight tested for the second time. GSLV-D5 will launch 1982 Kg GSAT-14, a communication satellite, into Geosynchronous Transfer Orbit (GTO). After reaching GTO, GSAT-14 will use its own propulsion system to reach its geostationary orbital home and will be stationed at 74º East longitude. GSAT-14 will help provide many satellite based communication services to the country including tele-education and telemedicine. GSLV-D5/GSAT-14 mission will be launched from the Second Launch Pad at Satish    Dhawan Space Centre SHAR (SDSC SHAR),Sriharikota. The flight duration of GSLV-D5 is 17 min 8 sec.


GSLV is a three-stage launch vehicle with solid, liquid and cryogenic stages. It is designed to inject 2 Ton class of communication satellites to Geosynchronous Transfer Orbit (GTO). The four liquid L40 strap-ons as well as the second stage of GSLV use storable liquid propellants. GSLV-D5 vehicle is configured with its first and second stages similar to the ones flown during earlier GSLV missions. The third stage is the indigenous cryogenic stage. The metallic payload fairing with a diameter of 3.4 metre is adopted for GSLV-D5. S-band telemetry and C-band transponders enable GSLV-D5 performance monitoring, tracking, range safety / flight safety and Preliminary Orbit Determination(POD).

Indigenous Cryogenic Upper Stage

Indigenous Cryogenic Upper Stage

A Cryogenic rocket stage is more efficient and provides more thrust for every kilogram of propellant it burns compared to solid and earth-storable liquid propellant rocket stages. Specific impulse (a measure of the efficiency) achievable with cryogenic propellants (liquid Hydrogen and liquid Oxygen) is much higher compared to earth storable liquid and solid propellants, giving it a substantial payload advantage. However, cryogenic stage is technically a very complex system compared to solid or earth-storable liquid propellant stages due to its use of propellants at extremely low temperatures and the associated thermal and structural problems. Oxygen liquifies at –183 deg C and Hydrogen at –253 deg C.The propellants,at these low temperatures are to be pumped using turbo pumps running at around 40,000 rpm. It also entails complex ground support systems like propellant storage and filling systems, cryo engine and stage test facilities, transportation and handling of cryo fluids and related safety aspects. ISRO’s Cryogenic Upper Stage Project (CUSP) envisaged the design and development of the indigenous Cryogenic Upper Stage to replace the stage procured from Russia and used in GSLV flights. The main engine and two smaller steering engines of CUS together develop a nominal thrust of 73.55 kN in vacuum. During the flight, CUS fires for a nominal duration of 720 seconds. Liquid Oxygen (LOX) and Liquid Hydrogen (LH2) from the respective tanks are fed by individual booster pumps to the main turbopump to ensure a high flow rate of propellants into the combustion chamber. Thrust control and mixture ratio control are achieved by two independent regulators. Two gimbaled steering engines provide for control of the stage during its thrusting phase.


GSAT-14 is the twenty third geostationary communication satellite of India built by ISRO. Four of GSAT-14’s predecessors were launched by GSLV during 2001, 2003, 2004 and 2007 respectively. After its commissioning, GSAT-14 will join the group of India’s nine operational geostationary satellites. The main objectives of GSAT-14 mission are:

  • To augment the in-orbit capacity of Extended C and Ku-band transponders 
  • To provide a platform for new experiments.

The cuboid shaped GSAT-14 has a lift-off mass of 1982 kg and the dry mass of the satellite is 851 kg.GSAT-14 structure is based on ISRO’s 2 ton class platform (I-2K satellite bus). The two solar arrays (each with two panels) of GSAT-14 together generate about 2600 W of power, while the light weight Lithium-Ion Batteries supply power during eclipse period. 

Some of the new experiments being flown on GSAT-14 are: 

  • Fiber Optic Gyro
  • Active Pixel Sun Sensor
  • Ka band beacon propagation studies
  • Thermal control coating experiments

Tags: Isro, Cryogenic, Gslv-d5, Gsat-14