Indian Space Research Organisation (ISRO) achieved a significant milestone by successfully launching its 100th mission from its Spaceport -Satish Dhawan Space Centre Sriharikota (SHAR), Andhra Pradesh on 29 January 2025. The GSLV-F-15 rocket carrying the NVS-02 satellite was launched from the second launch pad of the SHAR.In 1971 the first rocket- a sounding rocket RH -125 was launched from Sriharikota.
Key Points of GSLV-F15 Rocket
- The GSLV-F15 rocket was launched from the Second Launch Pad (SLP) of Satish Dhawan Space Centre at Sriharikota, India.
- GSLV-F15 was the 17th flight of India’s Geosynchronous Satellite Launch Vehicle (GSLV).
- It was the 11th successful launch using India’s indigenous cryogenic stage.
- The rocket’s payload fairing was a 3.4 meter diameter metal enclosure designed to provide protection to the satellite during flight.
- GSLV-F15 successfully placed the NVS-02 satellite into a Geosynchronous Transfer Orbit (GTO).
- This mission was the 8th operational flight of GSLV’s indigenous cryogenic stage.
NVS-02 Satellite
- NVS-02 is the second satellite in the second generation NVS series powering India’s NavIC system.
- It carries navigation payloads in L1, L5, and S bands as well as a C-band ranging payload.
- The satellite was designed, developed and integrated at U R Satellite Centre (URSC).
- The satellite weighs 2250 kg and is powered by about 3 KW of power.
- NVS-02 is placed in orbit at 111.75ºE.
- The satellite uses indigenous and procured atomic clocks to ensure accurate time keeping.
NavIC System
- NavIC is India’s independent regional navigation satellite system designed to provide precise position, waypoint, and time (PVT) services. The system provides coverage within India and up to about 1500 km outside the Indian territory.
Two types of services are provided under this system
- Standard Positioning Service (SPS): Through this service, position accuracy better than 20 meters and time accuracy better than 40 nanoseconds is provided, especially in the primary service area.
- Restricted Service (RS): This is a more secure and limited service, which is generally for authorized users. This system has been developed to ensure reliability and continuity of services.
Introduction and History of GSLV (Geosynchronous Satellite Launch Vehicle)
Introduction
- GSLV (Geosynchronous Satellite Launch Vehicle) is an expendable launch system, developed by ISRO.
- It has been used first in 2001. Since then it has been used in 15 missions.
- GSLV is known for its cryogenic third stage, which generates high thrust using liquid hydrogen and liquid oxygen, enabling it to carry heavy payloads.
- It is a three-stage rocket, consisting of solid rocket boosters, a liquid core stage, and a cryogenic upper stage.
- Some of the important missions launched by GSLV include Chandrayaan-2, India’s lunar mission.
- It is designed to put communication and weather satellites into high orbits.
- GSLV is the symbol of India’s indigenous satellite launching capability.
- GSLV is classified as a medium-lift launch vehicle, enabling it to put satellites into various orbits such as GTO, SSO, and LEO.
- GSLV rockets are commonly used to launch satellites like INSAT, GSAT (which includes South Asia Satellite), GISAT, NVS, and NISAR.
History
- Before GSLV, PSLV was in use since 1993 but it did not have the capability to launch heavy payloads into Geosynchronous Transfer Orbit (GTO).
- Realizing the strategic need to launch India’s INSAT satellites for national communication, meteorology, and other services, ISRO started the development of GSLV in the 1990s.
- The first GSLV experimental flight took off in 2000 carrying GSAT-1 satellite but the mission failed due to performance issues of the cryogenic stage.
- After overcoming technical challenges, the first successful test of indigenous cryogenic stage was conducted in 2014 with the successful launch of GSAT-14 satellite by GSLV-D5.
- From 2017 till date, GSLV has completed 6 consecutive successful missions, proving its reliability and developed capability.
Key Features of GSLV Rockets
Size
- Height: The height of GSLV is 49.13 m (161.2 ft) and with ogive payload fairing its height reaches 51.73 m.
- Diameter: The diameter of the rocket is 2.8 m (9 ft 2 in).
- Lift-off mass: The lift-off mass of the rocket is about 420 tonnes.
Payload Capacity
- Geosynchronous Transfer Orbit (GTO): GSLV is capable of carrying up to 2,250 kg of payload to GTO.
- Sun-synchronous orbit (SSO): It can deliver up to 3,000 kg of payload to SSO.
- Low Earth Orbit (LEO): The rocket can place up to 6,000 kg of payload in LEO.
Boosters
- The rocket has 4 L40 H boosters.
- Each booster has a propellant mass of 42,700 kilograms (94,100 lb).
Types of GSLV Rockets
GSLV Mark I
- GSLV Mark I used Russian cryogenic stage (CS) and was the initial version of GSLV.
- GSLV Mk.I was first tested on 18 April 2001.
- The first developmental flight had a 129 tonne first stage (S125) and was capable of carrying up to 1,500 kg of payload to geosynchronous transfer orbit (GTO).
- All GSLV Mark I flights have been conducted from Satish Dhawan Space Centre, Sriharikota.
- GSLV Mark I was used between 2001-2010, completing a total of 5 flights. A suborbital test was conducted in 2010, which was the last rocket in the series.
GSLV Mark II
- GSLV Mark II has indigenous CE-7.5 cryogenic engine. Earlier GSLV Mark II used Russian cryogenic engines, but now it uses Indian technology.
- In 2018, ISRO introduced a version of Vikas engine with 6% increased thrust for the first stage boosters, which was first demonstrated in the flight of GSAT-6A.
- GSLV Mk.II started its service on 15 April 2010 and is currently the active version.
- The last launch of GSLV Mk.II was on 29 January 2025.
GSLV Mk III (LVM-3)
- GSLV Mk III, also known as LVM-3, is the most powerful, advanced and latest version of the GSLV series.
- With a payload capability of up to 4 tonnes in GTO, it is designed for heavy payloads and has been used for important missions such as Chandrayaan-2 and Gaganyaan.
Use of Cryogenic Technology in GSLV
Cryogenic Technology in GSLV
- The Cryogenic Upper Stage (CUS) of GSLV uses liquid hydrogen (LH₂) and liquid oxygen (LOX) as propellants that power the upper stage of the rocket.
- The main engine and two steering engines deliver these propellants to the combustion chamber where they are ignited.
- The engines are driven by a gas generator cycle where the thrust and mixture ratios are carefully controlled.
- The steering engines control the direction of the rocket when it is in the thrust state.
Cryogenics
- Cryogenics is the science of materials at very low temperatures, generally below -153°C, in which gases such as hydrogen, nitrogen and oxygen turn into liquid form.
- In rocket propulsion, cryogenic fluids such as liquid hydrogen and liquid oxygen provide the power required for high performance engines, which are critical to maintaining payloads in high orbit.
Why Cryogenic Technology
- Cryogenic engines offer much higher efficiency and power than older liquid propulsion technologies.
- This enables GSLV to carry heavier payloads to Geosynchronous Transfer Orbit (GTO).
- The indigenous cryogenic engine (CE-7.5) is part of ISRO’s effort to develop self-reliant cryogenic technology for space exploration.
- The cryogenic stage of GSLV has been used in several important missions, such as Chandrayaan-2 mission and GSAT-19 satellite launch.