Geosynchronous Satellite Launch Vehicle (GSLV) is an Indian launch vehicle designed to place communication satellites in geostationary transfer orbit using a cryogenic third stage. Later cryogenic stages were developed in-house and inducted beginning with GSLV D5 in January 2014. In this article, we will discuss in detail regarding GSLV and Various Engine which will be helpful for UPSC exam preparation.

Stages of GSLV

First Stage

• The first stage employs a 138-tonne solid rocket motor with four liquid engine strap-on motors. The maximum thrust produced by this stage is 4700 kilo Newton.

Second Stage

• The second stage employs a liquid rocket engine known as the Vikas engine. It can produce a maximum thrust of 800 kilo Newtons.

Third Stage

• The third stage employs a cryogenic engine that runs on liquefied oxygen and hydrogen.
• In the initial launches, the Russian cryogenic engine in the CUS stage was used. Glavcosmos, a Russian company, built these engines.
• ISRO launched the Cryogenic Upper Stage Project in 1994 with the goal of developing India's own cryogenic engine and reducing reliance on foreign cryogenic engines.
• India's first cryogenic engine is the CE-7.5.

Types of Engines

1) Cryogenic Engine

• To escape Earth's gravitational pull, rocket engines require massive amounts of thrust.
• However, the chemicals used in engines are Hydrogen and Oxygen (Hydrogen as a fuel, and Oxygen as an oxidiser), which produce a good thrust and are found on Earth in the form of petrol.
• Carrying hydrogen and oxygen in gaseous form will necessitate a larger fuel chamber, increasing not only the size but also the weight of the rockets, implying an impossible task to send a launch vehicle into space.
• As the volume of propellant decreases, the solution is to use hydrogen and oxygen in liquid form or in cryogenic form, which is easier to transport.
• More thrust can be produced in less burning time as liquid density increases. These engines are known as cryogenic engines.
• Cryogenic fuel is used in rockets, spaceships, and satellites because ordinary fuel cannot be used in space due to the lack of a combustion-friendly environment.
• To keep this fuel liquid, it must be stored at an extremely low temperature (-253°Celsius).

2) Semi Cryogenic Engine

• In contrast to a cryogenic engine, a semi-cryogenic engine runs on refined kerosene rather than liquid hydrogen. As an Oxidiser, liquid oxygen is used.
• That is the benefit of using a Semi Cryogenic engine because it uses Refined Kerosene, which is lighter than liquid fuel and can be stored at room temperature.
• The combination of kerosene and liquid oxygen gives the rocket more thrust.
• Because refined kerosene takes up less space, it is possible to carry more propellant in the fuel compartment of a Semi Cryogenic engine.
• In comparison to a cryogenic engine, a semi cryogenic engine is more powerful, environmentally friendly, and cost effective.

Conclusion

The Geosynchronous Satellite Launch Vehicle (GSLV) stands as a remarkable achievement in India's space exploration journey, propelled by its advanced propulsion systems. The GSLV's two main engine configurations—the GSLV Mk II and GSLV Mk III—have ushered in a new era of capabilities and possibilities for the Indian Space Research Organisation (ISRO). These engines, the Vikas and the CE-20, showcase India's technological prowess and commitment to pushing the boundaries of space exploration.

FAQs

MCQs

1. What is the purpose of GSLV?

A) To launch satellites into low Earth orbit
B) To launch satellites into geostationary orbit
C) To launch crewed missions
D) To launch space probes

2. What engines are used in the GSLV launch vehicle?

A) Only solid engines
B) Solid, liquid, and cryogenic engines
C) Only liquid engines
D) Liquid and hybrid engines

3. Which of the following is true about the cryogenic engine in GSLV?

A) It uses solid fuels
B) It uses liquid hydrogen and liquid oxygen
C) It uses liquid methane and liquid oxygen
D) It uses nuclear fuel

4. What is the role of GSLV in India's space program?

A) To send crewed missions to space
B) To launch satellites into low Earth orbit
C) To launch heavier payloads into geostationary orbit
D) To explore other planets

5. How does the GSLV perform compared to PSLV?

A) GSLV can carry heavier payloads into lower orbits
B) GSLV is cheaper to operate
C) GSLV is designed for launching into geostationary orbits
D) GSLV uses only solid fuel engines

GS Mains Questions and Model Answers

Q1: Discuss the importance of the cryogenic engine in GSLV and its role in enhancing space exploration capabilities.

Answer: The cryogenic engine in GSLV is a critical component for space exploration as it provides higher efficiency and greater thrust. Cryogenic fuels, such as liquid hydrogen and liquid oxygen, offer a much higher specific impulse compared to conventional liquid propellants. This increased efficiency allows GSLV to carry heavier payloads, particularly for communication and meteorological satellites into geostationary orbits. The cryogenic stage also enhances the vehicle’s payload capacity, enabling India to conduct more advanced space missions, including those for communication, remote sensing, and scientific research. Furthermore, the successful development and deployment of cryogenic engines mark a significant achievement in India’s indigenous space capabilities, contributing to the country’s autonomy in space exploration.

Q2: Explain the role of GSLV in India’s ambitions for space exploration and its significance for national security.

Answer: GSLV plays a vital role in India’s space exploration program by providing a reliable means of launching heavier payloads into geostationary orbits. This ability is crucial for India’s ambitions to develop its communication and remote sensing satellites, which are essential for both civilian and military applications. Geostationary satellites, which remain fixed over a particular location on Earth, are important for national security, including defense communications, weather forecasting, and disaster management. GSLV's success strengthens India's space capabilities, allowing for more advanced satellite-based services that enhance national security. Additionally, the development of indigenous launch vehicle technology like GSLV is a step towards greater space autonomy and global space leadership.

Q3: How does the GSLV differ from PSLV in terms of payload capacity and mission objectives?

Answer: GSLV and PSLV are both crucial launch vehicles developed by ISRO, but they serve different purposes. GSLV is designed to carry heavier payloads into geostationary orbits, making it ideal for communication and weather satellites, which require precise positioning in space. In contrast, PSLV is optimized for lighter payloads, typically sending satellites into low Earth orbit (LEO) for scientific and remote sensing missions. The main difference between the two lies in their payload capacity, with GSLV able to carry payloads of up to 2,500 kg to geostationary orbits, while PSLV typically carries smaller payloads. Therefore, GSLV’s role is more focused on geosynchronous satellite launches, while PSLV is versatile and frequently used for launching smaller payloads into various orbits.

Previous Year Questions on Launch Vehicles

1. UPSC CSE Mains 2020 (GS Paper 3):

Question: "What are the advantages of using cryogenic engines in launch vehicles, and how does India’s GSLV benefit from this technology?"

Answer: Cryogenic engines are advantageous in launch vehicles due to their high specific impulse, which translates into better fuel efficiency. GSLV’s cryogenic stage allows for heavier payloads to be launched into geostationary orbits, improving India’s satellite launch capabilities significantly. The use of cryogenic engines in GSLV provides a greater payload capacity, making it indispensable for the launch of communication and meteorological satellites. Furthermore, the successful development of cryogenic technology places India among the few countries with this advanced capability, strengthening its position in the global space industry.

2. UPSC CSE Mains 2019 (GS Paper 3):

Question: "Explain the role of GSLV in enhancing India’s space exploration missions and its contribution to international space cooperation."

Answer: GSLV’s role in enhancing India’s space exploration is critical due to its capacity to launch larger payloads into geostationary orbits. This enables India to deploy advanced satellites for communication, meteorology, and scientific research. The ability to launch heavy payloads strengthens India’s autonomy in space exploration and satellite technology, contributing to national security and scientific advancement. Additionally, GSLV has facilitated international cooperation by offering reliable launch services to other nations, positioning India as a key player in the global space industry.