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Subject: Space Technology

  • Hoyle–Narlikar Theory of Gravity

    Why in the News?

    Jayant Narlikar, renowned Indian astrophysicist and Padma Vibhushan awardee, who co-developed the Hoyle–Narlikar Theory to refine Einstein’s Theory of Relativity, passed away in Pune at the age of 87.

    About Jayant Narlikar and His Contributions:

    • Early Life: Born in 1938 in Kolhapur, Maharashtra, and pursued a PhD at Cambridge University under Fred Hoyle.
    • Scientific Influence: Hoyle had earlier developed the steady-state theory with Bondi and Gold and coined the term “Big Bang” sarcastically in 1948.
    • Narlikar’s Belief: He argued that the universe always looks the same, as new matter fills the gaps created by expansion.
    • Critique of Big Bang: He believed the Big Bang theory includes unproven assumptions, especially about the sudden origin of all matter and energy.
    • Enduring Work: Despite steady-state theory’s decline, Narlikar’s contributions remain respected for their scientific depth and originality.

    What Is the Hoyle–Narlikar Theory?

    Fred Hoyle and Jayant Narlikar developed a theory to answer one of the most basic questions: Why do things have mass, and how are they connected to the rest of the universe?

    • Based on Mach’s Principle: They believed your mass isn’t just something you have on your own. Instead, it depends on your connection to everything else in the universe. That means even faraway stars and galaxies play a role in what you weigh.
    • Inertia Explained: In simple terms, when you feel resistance while trying to move (inertia), it’s because of the gravitational pull of all the matter in the universe acting on you at once.
    • Mass is Relative: Earth, the Sun, or even you don’t have a fixed mass. That mass is influenced by everything else that exists out there, no matter how far away it is.
    • C-field and Steady-State Model
      • New Idea – C-Field: They introduced the “creation field”, which creates new matter in space.
      • Universe Without a Start: Their steady-state theory says the universe has no beginning or end, is always expanding, and keeps its density constant.
      • Against the Big Bang: They believed the Big Bang couldn’t explain everything we see today.
      • Hydrogen Creation: They said hydrogen atoms form in space to fill in the gaps as the universe grows.
    • Issues with the Theory:
      • CMB Discovery (1965): Scientists found cosmic microwave background radiation, strong proof of the Big Bang.
      • Other Evidence: Later discoveries like young, chaotic galaxies and studies by Hawking and Penrose supported the Big Bang.
      • Current View: The Big Bang theory became more accepted, but Hoyle and Narlikar’s ideas are still respected for their scientific value.
    [UPSC 2018] Consider the following phenomena:

    1. Light is affected by gravity.

    2. The Universe is constantly expanding.

    3. Matter warps its surrounding space-time.

    Which of the above is/are the prediction/predictions of Albert Einstein’s General Theory of Relativity, often discussed in media?

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

     

  • 125 Years of Kodaikanal Solar Observatory (KoSO) 

    Why in the News?

    The Department of Posts has released a commemorative postage stamp to mark 125 years of the Kodaikanal Solar Observatory (KoSO)—one of India’s oldest and most significant astronomical research centres dedicated to studying the Sun.

    About the Kodaikanal Solar Observatory (KoSO):

    • Founding: Established in the late 19th century, KoSO was established in 1899 after atmospheric surveys by Charles Michie Smith.
    • Location: It is located in Kodaikanal, Tamil Nadu, in the Palani Hills, chosen for its excellent sky conditions.
    • Early Observations: Initially focused on observing sunspots, solar prominences, and solar radiation.
    • Modern Equipment: Now equipped with the H-alpha telescope (for flares and prominences) and WARM (for high-resolution sunspot imaging).
    • Institutional Role: Became part of the Indian Institute of Astrophysics (IIA) in April 1971.
    • Scientific Importance: KoSO contributes to understanding the Sun’s effect on Earth’s climate and space weather.

    Important Observations / Discoveries:

    • Evershed Effect (1909): Discovered by John Evershed, it was the first observation of radial gas outflows in sunspots, a key finding in solar physics.
    • Historic Solar Archive (1904–2017): Created one of the world’s longest continuous solar datasets.
    • Digitization: First Indian observatory to digitise solar data (since 1984); currently maintains a digital archive of 1.48 lakh images (~10 TB).
    • Wider Scientific Work: Extended research into cosmic rays, radio astronomy, ionospheric physics, and stellar astrophysics over the decades.
    [UPSC 2016] Discuss India’s achievements in the field of Space Science and Technology. How the application of this technology has helped India in its socio-economic development?

     

  • Chandrayaan-5 (LUPEX Mission) enters Preliminary Design Phase

    Why in the News?

    India and Japan have begun the preliminary design phase of the Chandrayaan-5 mission, also known as LUPEX (Lunar Polar Exploration).

    Back2Basics: Legacy of Chandrayaan Missions

    • Chandrayaan-1 (2008): First mission, focused on mineral and chemical mapping.
    • Chandrayaan-2 (2019): Orbiter mission with 98% success.
    • Chandrayaan-3 (2023): Achieved a historic soft landing on the Moon’s south pole.
    • Chandrayaan-4 (Upcoming, 2027):
      • It is a planned lunar sample return mission by ISRO, expected to launch around 2027, with the landing site near Statio Shiv Shakti at the lunar south pole.
      • The mission involves five modules launched on two LVM-3 rockets, later docked in Earth orbit to form an integrated spacecraft.
      • A robotic arm and drill will collect 2–3 kg of surface and sub-surface lunar samples for return to Earth.
      • The Re-entry Module (RM) will re-enter Earth’s atmosphere with the samples using ballistic re-entry, marking India’s first attempt at sample return.
    • Chandrayaan-5 / LUPEX: Aimed at deeper exploration with global participation.
    • Manned Lunar Mission: Prospected lunar landing by 2040.

    About Chandrayaan-5/LUPEX Mission:

    • It is a collaborative mission between ISRO and JAXA.
    • Approval: Cabinet approval for the mission was granted on March 10, 2025.
    • Launch: It will carry a 6.5-tonne payload and launch aboard Japan’s H3 rocket in 2027–28.
    • Collaboration: The lander is being developed by ISRO and the 350-kg rover by JAXA.
    • Duration: The mission is expected to last 100 days, with a possible extension of one year.
    • Mission Goals and Objectives:
      • Explore water and regolith in the lunar south pole’s Permanently Shadowed Regions (PSRs).
      • Drill into the Moon’s surface, analyse soil samples, and perform in-situ experiments.
      • Assess water content, quality, and analyse surface volatiles using advanced instrumentation.
      • Exploration of the far side of the Moon.

    Scientific Collaboration and Instruments:

    • A total of 7 scientific instruments will be onboard the mission.
    • ISRO’s Contribution: Development of the lander; creation of one sensor in a major four-sensor instrument.
    • JAXA’s Contribution: Development of the rover and three sensors in the same instrument; Rover is designed to climb 25° inclines and operate on a complex battery charging protocol.
    • ESA (European Space Agency): Developing a mass spectrometer.
    • NASA: Contributing neutron spectrometers.
    [UPSC 2009] In the context of space technology, what is Bhuvan, recently in the news?

    Options: (a) A mini satellite launched by ISRO for promoting the distance education in India (b) The name given to the next Moon Impact Probe, for Chandrayaan-II (c) A geoportal of ISRO with 3D imaging capabilities of India* (d) A space telescope developed by India

     

  • How did India develop genome edited rice?

    Why in the News?

    Union Agriculture Minister Shivraj Singh Chouhan recently said that India is the first country in the world to create rice varieties using genome editing technology.

    What are the new varieties?

    A team of researchers from different institutions, led by the Indian Council of Agricultural Research (ICAR), developed two new rice varieties — DRR Dhan 100 (called Kamala), made from the high-yielding Samba Mahsuri rice, and Pusa DST Rice 1, made from the Maruteru 1010 (MTU1010) variety.

    What are the benefits of the new rice varieties Kamala and Pusa DST Rice 1?

    • Higher Yield: Both varieties produce more rice per hectare than their parent strains. Eg: Kamala yields 5.37 tonnes/ha vs. Samba Mahsuri’s 4.5 tonnes/ha; Pusa DST Rice 1 yields 3,508 kg/ha, which is 9.66% more than MTU1010’s 3,199 kg/ha.
    • Drought Tolerance: Kamala is more resilient to drought, ensuring stable harvests during water shortages. Eg: Farmers can harvest good crops with less water in drought-prone areas using Kamala.
    • Early Maturity: Kamala matures 20 days earlier, reducing resource use and allowing faster crop cycles. Eg: Early harvest saves water and fertilizer, enabling farmers to grow a second crop sooner.
    • Salinity and Alkalinity Resistance: Pusa DST Rice 1 tolerates coastal salinity and alkaline soils better than its parent, boosting yield in tough environments. Eg: It yields 30.4% more under coastal salinity and 14.66% more under alkalinity than MTU1010.
    • Reduced Environmental Impact: Early maturity of Kamala lowers methane emissions from rice fields, helping fight climate change. Eg: Shorter growing period means less methane released compared to traditional rice varieties.

    Why are there objections to the genome-edited rice varieties?

    • Lack of Transparency: There is concern that the genome-edited rice varieties were announced without adequate field-level data being shared publicly, making the scientific claims appear premature. Eg: Venugopal Badaravada, a former ICAR governing body member, criticized the lack of transparency and was later expelled, raising concerns about institutional accountability.
    • Regulatory Concerns: Critics argue that exempting genome-edited crops (especially SDN-1 and SDN-2) from GM regulations is legally questionable and may bypass biosafety evaluations. Eg: The Coalition for a GM-Free India stated that de-regulating gene editing is “outright illegal” under India’s current biosafety framework.
    • Seed Sovereignty and Intellectual Property Rights (IPR): Activists fear that the gene-editing tools used are patented, which could threaten farmers’ seed rights and give control to private corporations. Eg: Concerns were raised about IPR entanglements with the technologies used in Kamala and Pusa DST Rice 1, potentially compromising India’s food and seed sovereignty.

    When will the new rice seeds be available for farmers?

    The Indian Council of Agricultural Research (ICAR) anticipates that certified seeds of these varieties will be available to farmers within two years, following the completion of necessary processes such as Intellectual Property Rights (IPR) registration and seed multiplication.

    Way forward: 

    • Ensure Transparent Evaluation: Conduct multi-location field trials and publicly share performance data to build scientific credibility and public trust.
    • Safeguard Farmer Rights and Regulatory Oversight: Develop a clear IPR policy and establish robust, independent biosafety review mechanisms to protect seed sovereignty and address legal concerns.

    Mains PYQ:

    [UPSC 2020] In what way have the science-based technologies triggered off striking changes in agriculture?

    Linkage: Genome editing is a science-based technology that represents a significant advancement capable of triggering changes in agriculture by developing improved crop varieties.

  • Asteroid YR4 might miss the Earth

    Why in the News?

    Asteroid YR4, discovered in December 2024 via Chile’s ATLAS telescope, was first thought to threaten Earth but was later ruled out. Scientists now focus on its potential Moon impact in 2032.

    Asteroid YR4 might miss the Earth

    About Asteroid 2024 YR4:

    • Asteroid 2024 YR4 was discovered in December 2024 by the ATLAS telescope located in Chile.
    • It is a near-Earth asteroid (NEA) whose orbit brings it within 1.3 AU (Earth-Sun distances) of Earth.
    • It is estimated to be 65 metres wide, roughly the size of a 10-storey building.
    • Initially, it was suspected to have a 3.1% chance of impacting Earth in 2032, triggering NASA’s highest-ever asteroid impact alert.
    • Subsequent tracking ruled out an Earth impact but indicated a 3.8% chance of hitting the Moon on December 22, 2032.
    • A Moon impact would create a 500 to 2,000-metre-wide crater and release energy 340 times more powerful than the Hiroshima bomb.
    • Despite being smaller than the 140m threshold for “potentially hazardous asteroids,” its unusual trajectory drew global scientific attention.
    • Scientists continue to observe YR4, including during a close approach in 2028, to refine its orbital predictions.

    Back2Basics: ATLAS Telescope

    • ATLAS (Asteroid Terrestrial-impact Last Alert System) is a NASA-funded early warning project for detecting small near-Earth objects (NEOs).
    • It is developed and operated by the University of Hawaii’s Institute for Astronomy.
    • As of 2025, ATLAS operates five telescopes in Hawaii, South Africa, Chile, and the Canary Islands.
    • Each telescope has a 0.5-meter Wright-Schmidt design, a 1-meter focal length, and a 110 MP CCD detector with a 7.4° field of view.
    • The system scans 20,000 square degrees of sky three times per night and provides 1–3 week warnings for asteroids 45–120 meters wide.
    • In addition to asteroids, ATLAS also discovers supernovae, comets, dwarf planets, and variable stars.

     

    [UPSC 2011] Comets show a perceptible glowing tail, while asteroids do not. Which of the statements given above is/are correct?

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

     

  • Gold’s Cosmic Origins from Magnetar Flares

    Why in the News?

    A new study by Columbia University, suggests that the universe may have an alternate mechanism for producing gold — not just in neutron star collisions, as previously believed, but also in magnetar flares.

    Gold's Cosmic Origins from Magnetar Flares

    What are Magnetars?

    • Magnetars are a rare type of neutron star with immensely strong magnetic fields, among the most powerful in the universe.
    • They are formed when a massive star collapses during a supernova, leaving a highly dense stellar core.
    • Due to magnetic instability, magnetars sometimes release intense flares of X-rays and gamma rays.
    • These flares can be millions of times stronger than typical solar flares.
    • A magnetar’s magnetic field is estimated to be about a thousand times stronger than that of ordinary neutron stars.

    r-Process in a Magnetar Flare:

    • The r-process (rapid neutron-capture process) forms heavy elements like gold, platinum, and uranium by rapidly attaching neutrons to atomic nuclei.
    • It was earlier believed to occur mainly in neutron star mergers.
    • In a 2024 study, scientists analysed a 2004 magnetar flare followed by delayed gamma-ray emissions, recorded by NASA’s Compton Gamma Ray Observatory.
    • The radiation patterns matched those of radioactive decay from r-process elements, suggesting neutron-rich nuclei were produced.
    • Around 1.9 septillion kilograms of matter was ejected at near-light speeds, marking the first direct evidence of r-process nucleosynthesis in a magnetar flare.

    Implications for Gold Formation:

    • The study shows that magnetar flares may also produce gold and other heavy elements, not just neutron star collisions.
    • This implies such elements could have formed earlier in the universe than previously believed.
    • The findings broaden our understanding of the origins of chemical elements in space.
    • It confirms that multiple astrophysical events contribute to the formation of heavy elements.
    • It also offers a new perspective on cosmic gamma-ray bursts and ancient stellar compositions.
    [UPSC 2012] Consider the following is/are cited by the scientists as evidence/evidences for the continued expansion of the universe?

    1. Detection of microwaves in space

    2. Observation of redshift phenomenon in space

    3. Movement of asteroids in space

    4. Occurrence of supernova explosions in space

    Select the correct answer using the code given below:

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

     

  • Kosmos 482 Mission

    Why in the News?

    A 500-kg piece of a Soviet spacecraft, part of the Kosmos 482 mission launched in 1972, is expected to crash back to Earth.

    About Kosmos 482 Mission:

    • Kosmos 482 was a Soviet space probe launched on March 31, 1972 as part of the Venera Program, aimed at exploring Venus.
    • It was launched just four days after its twin mission, Venera 8, which successfully landed on Venus 117 days later.
    • The mission’s goal was to:
      • Study Venus’s atmosphere and surface
      • Demonstrate technological and scientific superiority during the Cold War
    • Kosmos 482 was equipped with instruments to measure:
      • Temperature, pressure, and wind speed
      • Atmospheric gases and rock composition
      • Capable of transmitting data back to Earth
    • Venus was a target due to:
      • Speculation about life beneath its thick clouds
      • Its strategic importance in space exploration rivalry
    • Under the broader Venera Program (1961–1984):
      • 28 missions were launched toward Venus
      • 13 probes entered the atmosphere
      • 10 probes landed, but could only function for 23 minutes to 2 hours due to harsh surface conditions
    [UPSC 2014] Which of the following pairs is/are correctly matched?

    Spacecraft: Purpose

    1. Cassini-Huygens : Orbiting the Venus and transmitting data to the Earth.

    2. Messenger : Mapping and investigating.

    3. Voyager 1 and 2 : Exploring the outer solar system.

    Select the correct answer using the code given below.

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

     

  • Fracture Discovered in a Cosmic Bone of the Milky Way

    Why in the News?

    NASA has released an image of a fractured structure in the Milky Way’s galactic centre. The feature, named G359.13, was captured using X-ray data from Chandra and radio data from South Africa’s MeerKAT array.

    Fracture Discovered in a Cosmic Bone of the Milky Way

    What is G359.13?

    • G359.13 is a long, linear structure near the centre of the Milky Way.
    • It is often referred to as a cosmic bone due to its shape and density.
    • It stretches about 230 light-years in length, making it one of the longest and brightest features of its kind in the galaxy.
    • It lies about 26,000 light-years from Earth, close to the Milky Way’s centre.
    • For context, over 800 stars exist within a radius of 230 light-years from Earth—the same length as this cosmic bone.

    New Discovery: A Fracture in G359.13

    • Astronomers identified a distinct break or fracture in the structure’s continuous body.
    • An X-ray and radio source was also detected precisely at the location of the fracture.
    • Scientists believe a pulsar—a magnetised, rotating neutron star—collided with G359.13.
    • The pulsar was likely moving at a speed of 1–2 million miles per hour at the time of impact.
    • The collision disrupted the structure, creating a visible fracture.

    Back2Basics: What is a Pulsar?

    • A pulsar is a neutron star that emits beams of electromagnetic radiation from its magnetic poles.
    • Though only about 20 km in diameter, it is more massive than the Sun.
    • Pulsars rotate extremely rapidly, some spinning hundreds of times per second.
    • When their radiation beam crosses Earth’s line of sight, we observe pulses of radiation, hence the name.

     

    [UPSC 2003] The time taken by the sun to revolve around the centre of our galaxy is

    Options: (a) 25 million years (b) 100 million years (c) 250 million years* (d) 500 million years

     

  • Cosmic Clumpiness and the S8 Tension

    Why in the News?

    New research suggests that understanding the “clumpiness” of matter, measured by Sigma-8 (S8) Tension, could unlock key insights into the universe’s structure and complexity.

    What is S8?

    • S8 is a measure used by scientists to understand the distribution of matter across the universe, indicating how “clumpy” or evenly spread out the matter (like galaxies, stars, and dark matter) is.
    • High S8 tension means matter is clumped together in certain regions, while low S8 means it’s evenly distributed.
    • Scientists use S8 to study matter, including dark matter, which is invisible but makes up most of the universe.
    • The measurement of S8 helps explain how the universe fits together and has evolved since the Big Bang.
    • Recently, conflicting measurements of S8 have caused confusion, raising questions about our understanding of the universe.

    Implications for the ΛCDM Model:

    • The ΛCDM model (Lambda Cold Dark Matter) is the standard model explaining the universe’s structure, suggesting it’s mainly composed of dark matter and dark energy.
    • This model assumes that dark energy is causing the universe’s accelerating expansion.
    • S8 discrepancies may challenge the ΛCDM model, indicating a potential gap in our understanding of dark energy or dark matter.
    • Possible Implications:
      • Revised Theories: Scientists may need to adjust their model of the universe due to conflicting S8 values.
      • Re-thinking Dark Energy: If S8 measurements don’t align with predictions, dark energy might not behave as expected.
      • New Discoveries: The S8 tension could suggest undiscovered forces or particles influencing matter behavior.
      • Better Observations: Improved telescopes and surveys, like the Rubin Legacy Survey, may help clarify why S8 measurements conflict with predictions.
    [UPSC 2015] In the context of modern scientific research, consider the following statements about ‘IceCube’, a particle detector located at South Pole, which was recently in the news:

    (1) It is he world’s largest neutrino detector, encompassing a cubic km of ice. (2) It is a powerful telescope to search for dark matter. (3) It is buried deep in the ice. Which of the statements given above is/are correct?

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

     

  • DRDO achieves milestone in Scramjet Hypersonic Engine Development

    Why in the News?

    The DRDO Laboratory (DRDL), located in Hyderabad, successfully demonstrated long-duration Active Cooled Scramjet Subscale Combustor ground testing for over 1,000 seconds.

    About Hypersonic Cruise Missiles:

    • Hypersonic cruise missiles are advanced weapons capable of travelling at speeds greater than Mach 5 (approximately 6,100 km/h), making them 5x faster than the speed of sound.
    • These missiles use Scramjets (Supersonic Combustion Ramjets) powered by atmospheric oxygen, making them more efficient for long-duration travel compared to traditional missiles that carry their own oxidizers.
    • They maintain high speeds and are highly manoeuvrable, making them difficult to intercept by current missile defense systems.
    • They can strike targets at long ranges with minimal warning and penetrate advanced defense shields.

    DRDO’s Achievement:

    • The DRDO successfully conducted long-duration Active Cooled Scramjet Subscale Combustor ground testing for over 1,000 seconds.
    • This test advances India’s capability to develop hypersonic cruise missiles, validating the design of the scramjet combustor and the test facility, both crucial for developing air-breathing propulsion systems.
    • This paves the way for full-scale flight-worthy combustor testing, bringing India closer to developing functional hypersonic missiles and enhancing its defense capabilities.
    [UPSC 2023] Consider the following statements:

    1. Ballistic missiles are jet-propelled at subsonic speeds throughout their fights, 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?

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