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GS Paper: GS3-16.Achievements of Indians in Science & Technology

  • District Cooling as a Climate and Urban Solution for India

    Why in the News?

    With rising temperatures, prolonged heatwaves and increasing air conditioner use, experts are advocating district cooling systems as an energy efficient solution aligned with India’s climate and urban planning goals.

    What is District Cooling?

    • A centralised cooling system that supplies chilled water from one large plant to multiple buildings through insulated underground pipes.
    • Instead of each building installing separate chillers:
      • A central plant produces chilled water at 6 to 7°C.
      • Water circulates to buildings and absorbs indoor heat.
      • Returns at 12 to 14°C to be cooled again.
    • It works like a public utility similar to piped gas or electricity.
    [2010] What is the principle by which a cooling system (Radiator) in a motor car works? (a) Conduction only 

    (b) Convection 

    (c) Radiation only 

    (d) Both conduction and radiation

  • Safe Landing Patch Identified near Mons Mouton for Chandrayaan 4

    Why in the News

    A study by ISRO Space Applications Centre has identified a safe landing patch near Mons Mouton for Chandrayaan-4, India’s first lunar sample return mission.

    About Moon’s Mons Mouton

    • Mons Mouton is a large flat topped lunar mountain massif
    • Officially named by the International Astronomical Union

    Location

    • Situated in the south polar region of the Moon
    • Lies close to the rim of the South Pole Aitken Basin
    • Approximately 160 km from the lunar south pole

    Origin

    • Formed due to rim uplift during ancient massive asteroid impacts
    • Represents exposed deep lunar crust, rare and scientifically valuable

    Key Physical Features

    • Width of nearly 100 km
    • Elevation of about 6,000 metres above surrounding terrain
    • Rugged topography with craters and boulder fields
    • Unique illumination conditions
      • Some regions receive near continuous sunlight
      • Others remain in permanent shadow
    • Can be observed during favourable libration even with amateur telescopes
    [2009] India has recently landed its Moon Impact Probe on the Moon. Among the following countries, which one landed such probe on the Moon earlier? (a) Australia 

    (b) Canada 

    (c) China 

    (d) Japan

  • Sodium Ion Batteries and India’s Battery Strategy  

    Why in the News?

    A recent policy focused analysis highlighted sodium ion battery technology as a strategic alternative for India to reduce dependence on lithium ion batteries, strengthen energy security and address critical mineral supply risks.

    Background

    • Batteries are central to EVs, renewable energy storage and digital devices
    • Lithium ion batteries currently dominate due to high energy density and long cycle life
    • India faces high import dependence for lithium, cobalt and nickel

    India’s Current Battery Push

    • Advanced Chemistry Cell manufacturing supported under PLI scheme
    • About 40 GWh capacity allocated, but limited domestic upstream ecosystem
    • Heavy reliance on imported raw materials and components

    What are Sodium Ion Batteries

    • Batteries that use sodium instead of lithium as the charge carrier
    • Sodium is abundant and widely available
    • Compatible with existing lithium ion manufacturing lines with minor changes

    Performance Comparison

    • Lower energy density than lithium ion batteries
    • Suitable for grid storage, two wheelers and stationary applications

    Global Status

    • Around 70 GWh sodium ion capacity operational globally in 2025
    • Expected to reach nearly 400 GWh by 2030
    [2025] In the context of electric vehicle batteries, consider the following elements: I. Cobalt 

    II. Graphite 

    III. Lithium 

    IV. Nickel 

    How many of the above usually make up battery cathodes? 

    (a) Only one (b) Only two (c) Only three (d) All the four

  • Solid Fuel Ducted Ramjet (SFDR) Technology Test 2026

    Why in the News?

    Defence Research & Development Organisation successfully demonstrated Solid Fuel Ducted Ramjet (SFDR) technology on February 03, 2026 from Integrated Test Range, marking India’s entry into an elite group of nations with this advanced missile propulsion capability.

    About Solid Fuel Ducted Ramjet (SFDR)

    • An advanced air breathing propulsion system for long range air to air missiles
    • Uses solid fuel with controlled airflow for sustained thrust
    • Allows missiles to maintain high speed during terminal phase
    • Significantly increases range and no escape zone

    Key Highlights of the Test

    • All subsystems including nozzle less booster, SFDR motor and fuel flow controller performed as expected
    • Missile was boosted to the required Mach number before ramjet ignition
    • Performance validated through tracking instruments along the coast of the Bay of Bengal
    • Successful data capture confirmed stable combustion and thrust control

    Strategic Significance

    • Enables development of next generation long range air to air missiles
    • Provides major tactical advantage against hostile aircraft
    • Strengthens indigenous defence research and manufacturing
    • Reduces dependence on imported propulsion technologies
    [2023] Consider the following statements: 1. Ballistic missiles are jet-propelled at subsonic speeds throughout their flights, while cruise missiles are rocket-powered only in the initial phase of flight

    2. Agni-V is a medium-range supersonic cruise missile, while BrahMos is a solid-fuelled intercontinental ballistic missile

    Which of the statements given above is/are correct? 

    (a) 1 only (b) 2 only (c) Both 1 and 2 (d) Neither 1 nor 2

  • Long Range Anti Ship Hypersonic Glide Missile (LR AShM)

    Why in the News?

    India will publicly debut its Long Range Anti Ship Hypersonic Glide Missile (LR AShM) at the 77th Republic Day parade, marking India’s entry into the elite hypersonic anti ship weapons club.

    What is LR AShM?

    • Indigenous hypersonic glide missile (More than Mach 5 Speed)
    • Designed to engage high value naval targets such as aircraft carrier battle groups
    • Capable of very long range strikes with extreme speed and manoeuvrability

    Developed By

    • Defence Research and Development Organisation
    • For the Indian Navy
    • Intended mainly for coastal battery and maritime strike roles

    Aim

    • Enhance maritime deterrence in the Indian Ocean Region
    • Neutralise enemy surface combatants at stand off distances
    • Strengthen A2 AD Anti Access Area Denial capabilities through shore based mobile launchers
    [2023] Consider the following statements: 

    1. Ballistic missiles are jet-propelled at subsonic speeds throughout their flights, while cruise missiles are rocket-powered only in the initial phase of flight

    2. Agni-V is a medium-range supersonic cruise missile, while BrahMos is a solid-fuelled intercontinental ballistic missile

    Which of the statements given above is/are correct? 

    (a) 1 only (b) 2 only (c) Both 1 and 2 (d) Neither 1 nor 2

  • How reusability can lead to sustainable, cost effective access to space

    Why in the News

    Reusable rocket technology has shifted space activities from government-controlled, single-use rockets to a commercial, reuse-based model. Private companies, especially SpaceX, have repeatedly recovered and reused rocket stages, cutting launch costs by nearly five times and allowing more frequent launches. With the global space economy expected to cross USD 1 trillion by 2030, reusability marks a fundamental break from earlier disposable launch systems that dominated for decades.

    Reusable rocket

    1. It is a spacecraft designed to launch, land, and be refurbished for multiple flights.
    2. It drastically cuts space access costs by reusing expensive components like the booster, with SpaceX’s Falcon 9 leading the way.
    3. How They Work (Key Technologies)
      1. Vertical Takeoff & Landing (VTVL): Rockets launch vertically and use engines, grid fins (like on Falcon 9), and landing legs for controlled descent and landing back on Earth.
      2. Advanced Software: Sophisticated flight computers and software manage complex maneuvers like boost-back burns, re-entry burns, and final landing.
      3. Fuel Reserve: Reusable rockets carry extra fuel to perform landing burns, making them heavier but efficient.
      4. Refurbishment: After landing, components are inspected, refurbished, and prepared for the next flight, reducing the need to build new rockets.

    How does rocket fuel mass constrain space launches?

    1. Rocket Equation Constraint: Demonstrates that most launch mass consists of fuel, leaving less than 3-4% for payload in conventional designs.
    2. Propellant Dominance: Requires carrying fuel to lift fuel, creating diminishing returns for payload capacity.
    3. Cost Implication: Increases launch expenses as entire systems are discarded after one mission.

    Why are rockets designed with multiple stages?

    1. Stage Separation: Allows discarding empty tanks and engines to reduce mass during ascent.
    2. Efficiency Gain: Improves thrust-to-weight ratio as the vehicle ascends.
    3. Conventional Limitation: Most stages are used once and destroyed, increasing per-launch costs.

    How has reusability altered rocket engineering economics?

    1. Stage Recovery: Enables retrieval of high-value components such as engines and avionics.
    2. Manufacturing Shift: Reduces dependence on repeated fabrication of complex propulsion systems.
    3. Launch Frequency: Supports rapid turnaround and higher mission cadence.

    What operational innovations enable reusable launch systems?

    1. Precision Landing: Uses autonomous guidance, grid fins, and controlled burns for vertical recovery.
    2. Thermal and Structural Design: Ensures engines and stages withstand re-entry heat and stress.
    3. Refurbishment Protocols: Introduces inspection, testing, and component replacement cycles.

    Can a recovered rocket stage be reused multiple times?

    1. Reuse Cycles: First stages of Falcon-9 rockets have been reused over 30 times.
    2. Economic Threshold: Savings from reuse outweigh refurbishment and inspection costs.
    3. Reliability Assurance: Requires rigorous testing to maintain safety and mission assurance.

    How does reusability improve sustainability in space operations?

    1. Material Efficiency: Reduces consumption of metals, composites, and rare components.
    2. Debris Reduction: Limits discarded stages that contribute to space and ocean debris.
    3. Environmental Impact: Lowers lifecycle emissions by minimizing repeated manufacturing.

    What are the limitations of reusable rocket technology?

    1. Engineering Trade-offs: Recovery systems add mass, reducing payload capacity.
    2. Thermal Stress: Engines face extreme heat cycles during re-entry and relaunch.
    3. Economic Ceiling: Excessive inspection or refurbishment can negate cost benefits.

    Where does India stand in reusable launch vehicle development?

    1. ISRO Initiatives: Working on reusable launch vehicles (RLVs), winged spaceplane concepts, and vertical landing experiments.
    2. Two-Stage Focus: Aims to achieve orbital missions with fewer stages through high-efficiency propulsion.
    3. Private Sector Entry: Indian startups are exploring recovery-based launch solutions.
    4. Future Direction: Emphasis on recovery, reuse, and refurbishment for competitive access to space.

    Conclusion

    Reusable launch systems redefine space access by replacing disposable rockets with recoverable transportation platforms. By lowering costs, increasing mission frequency, and reducing material waste, reusability strengthens both economic viability and sustainability of space operations. For India, adopting reusability is essential to remain competitive in a rapidly commercialising global space economy.

    PYQ Relevance

    [UPSC 2016] Discuss India’s achievements in the field of Space Science and Technology. How has the application of this technology helped India in its socio-economic development?

    Linkage: India’s achievements in space technology, low-cost launch systems, planetary missions, and indigenous satellites, demonstrate technological self-reliance and innovation. Their application has directly supported socio-economic development through communication, disaster management, navigation, weather forecasting, and governance efficiency (GS III: Space Technology & Development).

  • Indigenous Light Water Reactor Push

    Why in the News?

    India is fast tracking the fabrication of an indigenous Light Water Reactor (LWR) as it opens the nuclear power sector to private participation and explores opportunities in the global nuclear export market.

    Key Development

    • The Department of Atomic Energy (DAE) is accelerating work on a 900 MWe indigenous LWR.
    • Design work began in 2015.
    • Objective is to complement India’s existing Pressurised Heavy Water Reactor (PHWR) fleet.
    • Indigenous LWR capability is expected to improve India’s bargaining power with foreign reactor vendors.

    Why LWRs Matter Globally

    • LWRs account for over 85 percent of global civil nuclear reactor capacity.
    • Used extensively by United States, Russia and France.
    • Dominant technology in international reactor trade and supply chains.
    • Without LWR integration, India risks limited access to global nuclear exports.

    LWR vs PHWR

    • Light Water Reactors

        • Use ordinary water as coolant and moderator
        • Require enriched uranium fuel
        • Simpler design, lower construction cost
        • Higher thermal efficiency
        • Strong economies of scale
    • Pressurised Heavy Water Reactors

      • Use heavy water (deuterium)
      • Operate on natural uranium
      • Core strength of India’s nuclear programme
      • Greater fuel flexibility
      • Less attractive in export markets dominated by LWRs

    Legal and Policy Context

    • The Sustainable Harnessing and Advancement of Nuclear Energy for Transforming India Act, 2025 enables:
      • Greater private sector participation
      • More imported LWR based projects
    • Addresses earlier liability concerns raised by foreign suppliers.
    • Supports projects like Kudankulam Nuclear Power Plant.

    Export and Strategic Angle

    • Indigenous LWR enhances India’s role in the global nuclear supply chain.
    • Emerging economies like UAE, Bangladesh, Saudi Arabia and Turkey are expanding nuclear capacity.
    • India could position itself as a supplier of:
      • PHWRs fuelled with thorium and low enriched uranium
      • Small Modular Reactors (SMRs) of 30 to 300 MWe

    Thorium and India

    • India has modest uranium but vast thorium reserves.
    • Using thorium with low enriched uranium in PHWRs can:
      • Ease fuel constraints
      • Support large scale nuclear expansion
      • Strengthen India’s unique reactor niche

    Prelims Pointers

    • LWRs dominate the global nuclear reactor market.
    • India’s proposed indigenous LWR capacity is 900 MWe.
    • PHWRs remain India’s technological strength.
    • Nuclear amendments aim to attract private and foreign investment.
    • SMRs are emerging as a tool of energy diplomacy, including by China.
    [2023] Consider the following statements: 

    Statement-I: India, despite having uranium deposits, depends on coal for most of its electricity production. 

    Statement-II: Uranium, enriched to the extent of at least 60%, is required for the production of electricity. 

    Which one of the following is correct in respect of the above statements? 

    (a) Both Statement-I and Statement-II are correct and Statement-II is the correct explanation for Statement-I 

    (b) Both Statement-I and Statement-II are correct and Statement-II is not the correct explanation for Statement-1 

    (c) Statement-I is correct but Statement-II is incorrect 

    (d) Statement-I is incorrect but Statement-II is correct

  • Indigenous Sodium Ion Battery Development in India

    Why in the News?

    The Chatterjee Group is considering commercial production of indigenous sodium ion batteries, following successful development of a high speed charging Na ion battery by its research arm.

    Key Development

    • Scientists at Research Institute for Sustainable Energy (RISE) have developed an India sourced sodium ion battery.
    • Battery charges up to 94 percent in 5 minutes.
    • Energy density: ~180 Wh per kg, comparable to lithium iron phosphate batteries.
    • Prototype may be ready for industrial scale deployment in 2 to 3 years.
    • Estimated commercial investment could reach 10 to 12 billion dollars.

    About Sodium Ion Batteries

    • Use sodium instead of lithium as the charge carrier.
    • Sodium is abundant, low cost and widely available.
    • Safer thermal profile compared to lithium ion batteries.

    Key advantages

    • No use of lithium, cobalt, nickel or copper.
    • Reduces dependence on critical mineral imports, especially from China.
    • Lower supply chain vulnerability.

    Commercial Potential Areas

    • Electric mobility, especially two and three wheelers due to fast charging needs.
    • Grid scale energy storage for renewable energy integration.
    • Off grid and rural energy systems where robust and low cost storage is required.
    [2025] In the context of electric vehicle batteries, consider the following elements: 

    I. Cobalt 

    II. Graphite 

    III. Lithium 

    IV. Nickel 

    How many of the above usually make up battery cathodes? 

    (a) Only one (b) Only two (c) Only three (d) All the four

  • Project Suncatcher

    Why in the News?

    Google Research unveiled Project Suncatcher, a research initiative exploring AI datacentres in low Earth orbit powered entirely by solar energy, aimed at addressing the rapidly rising electricity demand of advanced AI systems.

    What is Project Suncatcher

    • A concept and research programme
    • Proposes placing AI datacentres in Low Earth Orbit
    • Datacentres operate continuously on solar power
    • Designed to handle energy intensive AI workloads
    • Developed under Google Research

    Objectives

    • Reduce the energy footprint of AI
    • Enable round the clock clean solar power
    • Decouple AI compute growth from
      • Terrestrial power grids
      • Land constraints
      • Water intensive cooling systems
    • Support long term scalability of AI infrastructure

    Prelims Pointers

    • Orbit used: Low Earth Orbit
    • Power source: Solar energy only
    • Developed by: Google Research
    • Key orbit type: Sun synchronous orbit
    • Core challenge addressed: AI energy demand
    • Emphasis on inter satellite communication over Earth links
    [2020] With the present state of development, Artificial Intelligence can effectively do which of the following? 

    1. Bring down electricity consumption in industrial units 

    2. Create meaningful short stories and songs 

    3. Disease diagnosis 

    4. Text-to-Speech Conversion 

    5. Wireless transmission of electrical energy 

    Select the correct answer using the code given below: 

    (a) 1, 2, 3 and 5 only (b) 1, 3 and 4 only (c) 2, 4 and 5 only (d) 1, 2, 3, 4 and 5

  • Bio Safety Level 4 Containment Facility in Gandhinagar

    Why in the News?

    Union Home Minister Amit Shah laid the foundation stone of a Bio Safety Level 4 Containment Facility in Gandhinagar, describing it as a national health shield and a major step towards advanced health security and biotechnology.

    What is a BSL-4 Facility?

    • Bio Safety Level 4 is the highest level of biological containment
    • Designed to handle extremely dangerous and lethal pathogens
    • Pathogens are often
      • Highly infectious
      • Transmitted via air or contact
      • Without proven vaccines or treatments
    • Work conducted under strict international biosafety protocols
    • Scientists wear positive pressure suits and work in sealed environments

    Pathogens to be Studied at Gandhinagar Facility

    • Ebola virus, Marburg virus, Crimean-Congo Hemorrhagic Fever virus, Kyasanur Forest Disease virus, and Nipah virus

    BSL Facilities in India

    • Only civilian BSL 4 lab currently operational at National Institute of Virology
    • Defence BSL 4 lab established by DRDO in Gwalior in 2024
    • High security animal disease labs
      • National Institute of High Security Animal Diseases with ABSL 3 plus
      • International Centre for Foot and Mouth Disease with ABSL 3Ag

    Prelims Pointers

    • BSL 4 is the highest biosafety level
    • Handles lethal and exotic pathogens
    • Gandhinagar lab is
      • Second civilian BSL 4 in India
      • First fully state funded BSL 4 facility
    • Supports One Health approach linking human and animal health
    • Enhances India’s pandemic readiness and biotech capacity
    [2021] Consider the following: 

    1. Bacteria 

    2. Fungi 

    3. Virus

    Which of the above can be cultured in artificial/synthetic medium? 

    (a) 1 and 2 only (b) 2 and 3 only (c) 1 and 3 only (d) 1, 2 and 3