S and T (Paper 5) – Class 4 – (E/M) – Group 1 (Mains Test Series)


7) What is satellite navigation? Write a note on Navigation with Indian Constellation (NAVIC).

Kalyan Sir OnlineIAS.com

Ans) Satellite Navigation: It is a system that uses satellites to provide positioning, navigation and tracking of objects fitted with a receiver. A satellite navigation system with a global coverage is termed as ‘Global Satellite Navigation System’. Presently, the GPS of USA, GLONASS of Russia and Galileo of European Union (scheduled to be operational from 2020) are global systems. China is in the process of expanding its regional BeiDou navigation system into global by 2020.

India, France and Japan have developed regional navigation systems.

The NAVIC or Indian Regional Navigation Satellite System (IRNSS) is an independent satellite based regional navigation system developed indigenously by ISRO. It is a constellation of seven satellites namely IRNSS-1B, 1C, 1D, 1E, 1F and 1G and 1I of which three are in geostationary and four are in geo-synchronous orbit.

Kalyan Sir OnlineIAS.com

The system covers entire India and a region extending 1,500 km area around the country’s borders. This indigenous satellite-based navigation system is considered a deep strategic asset.

The NAVIC system has both civilian and military uses. Moreover, it helps not just in land navigation but also in marine and aerial navigation. It offers wide services like terrestrial and marine navigation, disaster management, vehicle tracking and fleet management visual and voice navigation for drivers.

8) What are the advantages of cryogenic engine? Write a note on ISRO’s indigenously developed cryogenic engines and where they are used?

Kalyan Sir OnlineIAS.com

Ans) A cryogenic rocket engine uses a cryogenic fuel and oxidizer. Cryogenic fuels are fuels that require storage at extremely low temperatures in order to maintain them in a liquid state. The fuel and oxidizer are both gases liquefied and stored at very low temperatures. Cryogenic fuels are mostly liquefied gases such as liquid hydrogen. Oxygen liquefies at -183 degrees Celsius and hydrogen liquefies at -253 degrees Celsius.

Often, liquid oxygen is mistakenly called cryogenic fuel, though it is actually an oxidizer and not a fuel. Various cryogenic fuel-oxidizer combinations have been tried but the combination of liquid hydrogen and liquid oxygen is the most widely used.

Kalyan Sir OnlineIAS.com

Cryogenic engine is a very complex system, due to the use of propellants at extremely low temperature. It also requires complex ground support systems like propellant storage and filling systems, transportation and handling of cryogenic fluids and testing facilities.

ISRO has developed two cryogenic engines. The third stage of GSLV uses indigenously developed Cryogenic Engine known as CE-7.5. It is India’s first cryogenic engine, developed by the Liquid Propulsion Systems (LPSC) of ISRO. The cryogenic upper stage of GSLV Mk-III, India’s most powerful launch vehicle is powered by Cryogenic Engine (CE)-20 which is India’s largest cryogenic engine, designed and developed by the Liquid Propulsion Systems Centre.

Kalyan Sir OnlineIAS.com

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