Astronomy & Space Technology

Eyes in Orbit: India’s Private Leap in Space Surveillance

Context: India’s private satellite Aerospace First Runner (AFR) achieved a major milestone in Space Situational Awareness (SSA) by tracking and imaging the International Space Station (ISS) from orbit — the first publicly known case of an Indian private satellite performing space-to-space imaging (“in-orbit snooping”).

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India’s First Private Non-Earth Imaging Satellite

The AFR satellite marks a shift in India’s space ecosystem from state-led missions to private-sector deep-space capabilities. Built by Azista BST Aerospace (ABA), an Indo-German joint venture, the 80-kg satellite was launched in June 2023 aboard SpaceX’s Transporter-8 mission into a Sun-Synchronous Orbit (SSO).

Though primarily designed as an optical Earth-observation satellite with panchromatic and multispectral cameras, AFR demonstrated the ability to track and image another satellite — the International Space Station — from orbit. This capability, termed Non-Earth Imaging (NEI) or space-to-space imaging, involves satellites observing objects in orbit rather than Earth.

Strategic Significance for Space Situational Awareness

Space Situational Awareness (SSA) refers to tracking and monitoring all objects in Earth’s orbit to ensure safe and secure space operations. AFR’s achievement has major implications:

  • Orbital surveillance: Ability to inspect satellites, space debris, or hostile spacecraft.
  • Collision avoidance: Imaging and tracking improve orbital safety and debris mitigation.
  • Strategic security: Dual-use potential for defence, intelligence, and anti-satellite monitoring.
  • Private capability: Demonstrates India’s growing commercial space competence under IN-SPACe reforms.

With global satellite numbers rising rapidly (over 9,000 active satellites), SSA has become a critical domain for space-faring nations.

Technical Profile of AFR

  • Mass: ~80 kg small satellite
  • Orbit: Sun-Synchronous Orbit (~500–600 km altitude)
  • Payload: Wide-swath optical cameras (panchromatic + multispectral)
  • Primary Role: Earth observation (agriculture, disasters, urban planning)
  • Advanced Capability: Space-to-space imaging (ISS tracking)

The ability to reorient optical sensors to image another fast-moving orbital object requires precise attitude control, tracking algorithms, and orbital mechanics modelling — indicating high technological maturity for a private satellite.

Applications Beyond Space Surveillance

While SSA is the headline achievement, AFR continues to support conventional Earth-observation uses:

  • Crop health and precision agriculture
  • Disaster mapping and damage assessment
  • Urban infrastructure monitoring
  • Environmental and land-use analysis

Thus, AFR demonstrates the convergence of civil, commercial, and strategic space capabilities in India’s emerging private space sector.

India’s Expanding Private Space Ecosystem

Since the 2020 space reforms, India has enabled private players through:

  • IN-SPACe regulatory facilitation
  • Commercial launch access (ISRO infrastructure)
  • Foreign collaboration and manufacturing
  • Small-satellite market participation

AFR’s success positions India among a small group of nations capable of operational space-to-space imaging, a frontier technology in orbital security.

Conclusion

The AFR satellite’s in-orbit imaging of the ISS marks a watershed moment for India’s private space sector and SSA capability. It signals India’s transition from Earth observation to orbital domain awareness, strengthening both commercial competitiveness and strategic autonomy in space.

Launch of Communication Satellite-03 (CMS-03)

Context: The Indian Space Research Organisation (ISRO) successfully launched the CMS-03 communication satellite aboard the LVM3-M5 rocket from the Satish Dhawan Space Centre, Sriharikota. The mission strengthens India’s strategic naval communication capability across the Indian Ocean Region (IOR).

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About CMS-03 (GSAT-7R)

CMS-03, also referred to as GSAT-7R, is a dedicated multi-band military communication satellite designed for the Indian Navy. It provides secure, encrypted, high-bandwidth, real-time communication between naval ships, submarines, maritime aircraft, and land-based command centres.

It will replace the ageing GSAT-7 (Rukmini) launched in 2013, ensuring continuity and upgradation of maritime network systems under India’s naval digital communication strategy.

Strategic Importance

  • Enhances Maritime Domain Awareness: Supports naval operations, surveillance, anti-submarine missions, and fleet coordination.
  • Secure Naval Communication Layer: Ensures communication remains protected from interception and cyber threats.
  • Strengthens Blue-Water Naval Capabilities: Enables the Navy to operate effectively beyond the Indian coastline, supporting India’s vision of security and stability in the Indian Ocean Region.
  • Force Multiplier for Jointness: Can be integrated with communication systems of the Army and Air Force for tri-service operational synergy, aligning with Theatre Command goals.

Launch Vehicle: LVM3-M5

The mission used Launch Vehicle Mark-3 (LVM3-M5), popularly known as “Bahubali” due to its heavy-lift capability and reliability.

Key Features of LVM3:

ComponentTypeFunction
First StageSolid Booster (S200)Provides initial thrust for liftoff
Second StageLiquid Core Stage (L110)Sustains powered ascent
Third StageCryogenic Upper Stage (C25)Places the spacecraft accurately in orbit
  • Lift Capability: Up to 4 tonnes to Geostationary Transfer Orbit (GTO)
  • Success Rate: 100% in operational heavy-lift missions
  • Significance: It also launched Chandrayaan-3 and Gaganyaan test missions, showcasing ISRO’s mastery in strategic and scientific payload launches.

Way Forward

CMS-03 reinforces India’s Aatmanirbhar (indigenous) capabilities in defence satellite systems. It aligns with long-term goals of:

  • Net Security Provider role in IOR
  • Space-based naval surveillance
  • Expansion of India’s military satellite constellation

Crew Escape System in Gaganyaan Mission

Context: The Indian Space Research Organisation (ISRO) has recently highlighted the functioning of the Crew Escape System (CES) — a critical safety mechanism integral to India’s Gaganyaan Mission, which aims to send Indian astronauts into Low Earth Orbit (LEO) at about 400 km altitude and bring them back safely.

About Gaganyaan Mission

  • Objective: To demonstrate India’s human spaceflight capability by launching a 3-member crew into LEO for up to 3 days.
  • Launch Vehicle: Human-rated LVM3 (HLVM3) rocket.
  • Launch Site: Satish Dhawan Space Centre (SDSC), Sriharikota.
  • Timeline: The first uncrewed test flights are planned before the final crewed mission, expected around 2025–26.
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Crew Escape System (CES): Ensuring Astronaut Safety

The Crew Escape System is a safety abort mechanism designed to protect astronauts in the event of an anomaly during launch or ascent.

Purpose

To rapidly separate the Crew Module (CM) carrying astronauts from a malfunctioning rocket and ensure a safe return to Earth.

Placement

  • Mounted at the forward end of the HLVM3 rocket.
  • Equipped with multiple high-burn-rate solid motors for swift response.

Working Mechanism

  1. Emergency Detection: Sensors detect a malfunction in the launch vehicle.
  2. Separation: The CES activates its solid motors to pull the Crew Module away from the rocket within milliseconds.
  3. Descent Phase: After achieving a safe distance, parachutes deploy for controlled descent.
  4. Recovery: The module splashes down in the sea, where recovery teams retrieve the crew.

Test and Validation

  • A dedicated Test Vehicle powered by a Vikas engine has been developed to validate CES functionality.
  • The TV-D1 (Test Vehicle Demonstration 1) mission successfully demonstrated the abort and recovery sequence, marking a key milestone for Gaganyaan.

Types of Crew Escape Systems

TypeMechanismExample
Puller TypeUses solid motors to pull the Crew Module away from the rocket.Gaganyaan (ISRO)
Pusher TypeUses compact liquid engines to push the module away from the rocket.SpaceX Falcon 9 (Dragon Capsule)

Significance

  • Ensures astronaut safety in the most critical phase of flight.
  • Enhances public confidence in India’s human spaceflight programme.
  • Positions India among nations with advanced crewed launch safety systems, alongside the U.S., Russia, and China.

Mars Rover Perseverance discovers Potential Biosignature in Mars 

Context: NASA’s Mars rover Perseverance (exploring the Martian surface since 2021) has found the strongest signs yet that some form of life may have existed on Mars in the past.

Relevance of the Topic: Prelims: NASA’s Mars rover Perseverance findings; NASA’s Perseverance Mission.

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Perseverance’s Finding:

  • NASA's Perseverance rover discovered leopard spots on a reddish rock nicknamed “Cheyava Falls” in Mars' Jezero Crater in 2024.
  • The rock was found to contain clay and silt, which are known on Earth to preserve microbial life effectively.
  • The analysis also revealed the presence of organic carbon, sulphur, oxidised iron (rust), and phosphorus.
  • These minerals could have formed through biological activity but may also have resulted from purely chemical, non-biological processes.
  • The rock sample has been described as containing a “potential biosignature”, but not yet confirmed as evidence of life.

What are Biosignatures?

  • Biosignatures are objects, structures, or chemical compositions that may have a biological origin. They indicate the possible presence or activity of living organisms, either in the past or present.
  • A biosignature is any substance such as an element, isotope, or molecule or phenomenon that provides scientific evidence of past or present life.

Significance of the Finding

  • This is the closest NASA has ever come to detecting signs of life on Mars.
  • The discovery has the potential to revolutionise our understanding of Mars’s history and its capacity to host life.
  • The clay-rich nature of the sample is particularly important, as clay is known to be an excellent preserver of microbial signatures on Earth.

However, the finding does not conclusively prove the existence of life on Mars. The structures and chemical compositions detected could also be explained by non-living (abiotic) processes.

NASA’s Perseverance Mission (Mars 2020 Mission)

  • Launched: 2020. Landed in Mars: Feb 2021 
  • Rover: NASA’s 4th generation Mars Rover. It is the most advanced, most expensive & most sophisticated mobile laboratory sent to Mars till date. It is different from previous missions as it can drill & collect core samples of most promising rocks & soils. The rover landed at Jezero Crater - an ancient river delta that has rocks and minerals that could only form in water.
  • Ingenuity Helicopter: Autonomous helicopter that operated on Mars till January 2024. Travelled to Mars attached to the belly of the Perseverance rover and was deployed to the surface after landing in Jezero Crater. First aircraft to conduct a powered and controlled extra-terrestrial flight on a planet after Earth. 
  • Objectives:
    • To look for biosignatures in either the chemical measurements or morphological observations, in the dried-up lakebed at Jezero Crater. 
    • To demonstrate technology for future robotic and human exploration. Perseverance will produce oxygen on the Martian surface for the first time, using atmospheric CO2 from the Martian atmosphere.
  • Perseverance will drill and collect rock samples that will be returned to Earth by a subsequent European Space Agency/NASA mission in 2030s. Perseverance carries the Radar Imager for Mars’ Subsurface Experiment (RIMFAX). RIMFAX will provide high resolution mapping of the subsurface structure at the landing site. 
  • Power source: It has a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) which converts heat from the natural radioactive decay of plutonium (Plutonium Dioxide) into electricity.

Scientists discover rare Quadruple Star System in Milky Way

Context: Scientists have discovered an extremely rare quadruple star system in the Milky Way. The system known as UPM J1040-3551 AabBab consists of a pair of cold brown dwarfs orbiting a pair of young red dwarf stars.

Relevance of the Topic: Prelims: Key facts about Dwarf stars. 

What are Brown Dwarfs?

  • Brown dwarfs are substellar objects that have more mass than the biggest gas giant planets, but less than the least massive main-sequence stars. 
  • They form like stars from collapsing clouds of gas and dust. Their atmospheres can consist of clouds and molecules like H2O. Their mass is approximately 13 to 80 times that of Jupiter. 
  • They are not massive enough to sustain nuclear fusion of Hydrogen into Helium in their cores (unlike the main-sequence stars). So, they are often known as “failed stars”. However, they emit some light and heat from the fusion of deuterium (2H). 
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Why are Brown Dwarfs difficult to detect?

  • Brown dwarfs can be difficult to detect as they are cold and faint. As a result, astronomers typically search for brown dwarfs orbiting companion stars, which often burn brighter. Measuring the brighter stars can be useful for estimating the properties of the fainter brown dwarfs, like their age, temperature and composition. 

Brown dwarfs are usually single, and hence the current findings are exciting because the chances of a low-mass brown dwarf having a companion are less than 5%.

Why do scientists study Brown Dwarfs?

  • Brown dwarfs can help astronomers better understand the conditions that are necessary for the formation of stars and planets.
  • Determining the abundance and distribution of brown dwarfs gives key information on the distribution of mass in the universe to astronomers (much of the universe’s mass has thus far been undetectable and is known as dark matter).

The findings would help in better understanding brown dwarfs which are difficult to detect and examine.

ISRO holds Air Drop Test for Gaganyaan Mission

Context: Indian Space Research Organisation (ISRO) successfully carried out its first Integrated Air Drop Test (IADT-1) at Sriharikota, a critical milestone in preparations for Gaganyaan Mission- the country’s maiden human spaceflight programme. 

Relevance of the Topic:Prelims: Key facts about Gaganyaan Mission.  

Integrated Air Drop Test (IADT)

  • The first Integrated Air Drop Test was conducted for an end-to-end demonstration of the parachute-based deceleration system for the Gaganyaan Mission. 
  • The IADT is a specialised trial to ensure the parachute system designed for the Gaganyaan crew module performs reliably in real-world conditions.
    • During the test, a dummy crew capsule weighing around 5 tonnes was lifted up through the air by a Chinook helicopter, and then dropped. 
    • As it descended through a few kms, its main parachutes had to open in a specific sequence to decelerate the capsule to a safe splashdown speed.
  • During an actual flight with astronauts, the main parachutes will have to deploy after the capsule has re-entered the atmosphere and has been slowed first by the heat shields and drogue parachutes. 
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Significance: 

  • The ascent, descent, and post-splashdown phases of the Gaganyaan mission are expected to be the most risky for the astronauts. The successful conduction of the first Integrated Air Drop Test (IADT-01) is vital to ensure the safety of astronauts in the upcoming Gaganyaan Mission. 

Gaganyaan Mission

  • ISRO’s ambitious human spaceflight mission which will carry 3 astronauts (Vyomanauts) to Low Earth Orbit  (400 kilometres) for a 3-days mission, and bring them back safely to Earth by landing in Indian sea-waters.
  • Expected launch: Crewed launch is scheduled for the first quarter of 2027.
  • Launch Vehicle: Human Rated LVM3.
  • Human Space Flight Centre will coordinate the programme, and will be responsible for the implementation of the project. 
  • Once completed, India will become the world's fourth nation to conduct independent human spaceflight after Russia, United States and China.

Components of Gaganyaan Mission: 

  • Crew Module: A crew module and service module. The crew members have been shortlisted by the IAF and ISRO. The crew will perform micro-gravity and other scientific experiments.
  • Crew Module Atmospheric Re-entry Experiment (CARE): 
    • Gaganyaan would return back to Earth. While re-entering Earth’s atmosphere, the spacecraft needs to withstand very high temperatures created due to atmospheric friction. 
    • A prior critical experiment was carried out in 2014 along with LVM3, when the CARE capsule successfully demonstrated that it could survive atmospheric re-entry.
  • Crew Escape System- PAT: Crew Escape System is an emergency accident avoidance measure. In 2018, ISRO completed the first successful flight ‘pad abort test’ or Crew Escape System.
  • Environmental Control & Life Support System ECLSS: ECLSS will:
    • Maintain steady cabin pressure and air composition 
    • Remove carbon dioxide and other harmful gases
    • Control temperature and humidity
    • Manage parameters like fire detection and suppression
  • Vyom Mitra: ISRO’s female humanoid robot that will test-flight Gaganyaan.

Preparatory work for Gaganyaan Mission: 

The major preparatory work for Gaganyaan had already been completed. 

  • Propulsion systems for the crew module and service module have been developed and tested. 
  • Environmental Control and Life Support System (ECLSS) engineering model has been realised. 
  • Crew Escape System (CES): five types of motors developed and static tested.
  • Infrastructure had been established for the orbital module preparation facility, Gaganyaan Control Centre, Gaganyaan control facility, crew training facility, and second launch pad modifications. 
  • After successful execution of IADT-01, ISRO will conduct two critical trials before the actual Gaganyaan Mission carrying astronauts. It includes-
    • Second Test Vehicle Mission (TV-D2): will put to test the crew escape system (CES) under critical conditions.
    • Uncrewed Gaganyaan-1 (G1) flight: The unmanned spacecraft will be launched aboard a human-rated LVM3 rocket. The mission will also have on board Vyommitra, the humanoid robot developed by the ISRO. 

Vikram Sarabhai Space Centre (VSSC) plays major role: 

  • VSSC had a major role in IADT-01, being responsible for 90% of the activities alongside the Human Space Flight Centre (HSFC) and SDSC-SHAR.

IADT-01 successfully demonstrated the parachute-based crew module deceleration system for Gaganyaan Mission. 

India needs a National Space Law

Context: India’s space programme has achieved remarkable milestones from the cost-effective success of Mangalyaan (2014) to the historic soft landing of Chandrayaan-3 (2023) and the upcoming Gaganyaan mission. These achievements have positioned India among the top spacefaring nations. 

However, India lacks a comprehensive National Space Law which is essential to regulate private participation, ensure accountability, and align with international obligations.

Relevance of the Topic: Prelims: India's and Global Space Legislation.Mains: Why India Need for National Space Legislation? 

Global Space Legislation

The Outer Space Treaty of 1967 is the foundational legal framework for outer space.

Outer Space Treaty of 1967: 

  • It declares space to be the province of all mankind
  • Prohibits any national appropriation of celestial bodies, and 
  • Makes states responsible for all space activities conducted under their jurisdiction, including those by private actors.
  • Its companion agreements create binding frameworks of rights, responsibilities, and liability rules. 

Companion Agreements of OST 1967: 

  • Liability Convention 1972: Establishes state responsibility for damages caused by space objects.
  • Registration Convention 1976: Mandates registration of space objects.
  • Moon Agreement 1979: Treats space resources as “common heritage of mankind” (India is not a party).

Limitations: 

  • These treaties are not self-executing. They need to be translated into national laws for effective enforcement.

India’s Current Legal & Policy Framework

India has ratified the key UN space treaties but it is still in the process of enacting comprehensive national space legislation. Current regulatory measures include : 

  • Indian Space Policy, 2023: outlines roles of government and private entities.
  • IN-SPACe (Indian National Space Promotion and Authorisation Centre): Regulator for non-governmental space activities.
  • Catalogue of Indian Standards for Space Industry: Provides technical safety guidelines.
  • Norms, Guidelines and Procedures (NPG), 2023: Framework for authorisation of space activities.

Need for National Space Legislation: 

  • International Obligations: Under Article VI of the OST, India is internationally liable for activities of private companies. Without national law, India risks treaty violations or arbitrary regulation.
  • Predictability & Legal Clarity: National space legislation offers predictability, legal clarity, and a stable regulatory environment for both government and private actors, critical for attracting private investments.
  • Industry Concerns: 
    • IN-SPACe lacks statutory authority; its decisions are vulnerable to procedural challenges.
    • Companies face delays due to the dual-use nature of space technology (defence and civilian), requiring multiple ministry clearances.
    • Unclear FDI rules and lack of affordable third-party insurance hinder startups.
    • Weak IPR protection risks migration of talent to IP-friendly jurisdictions.
  • Strategic Importance: Space technologies are dual-use and critical for national security, absence of legal clarity can weaken strategic autonomy in space.

At present, more than 20 countries including the U.S., Luxembourg, and Japan already have national space legislation. To compete in this rapidly expanding market which is projected to reach $1 trillion globally by 2040, India cannot afford regulatory ambiguity.

In the words of UNOOSA, “policy signals intent, but law creates enforceable structure.” For India to lead the new space age, enacting this law is no longer optional but an imperative.

India’s first private constellation of Earth Observation Satellites

Context: The Indian National Space Promotion and Authorisation Centre (IN-SPACe) announced the selection of a consortium led by Google-backed PixxelSpace to design, build and operate India’s first fully-indigenous commercial Earth Observation (EO) satellite constellation, under the public-private partnership (PPP) model.

Relevance of the Topic:Prelims: Key facts about India’s first private constellation of Earth Observation Satellites. 
Mains: Commercialisation of the Space Sector in India. 

India’s first private constellation of Earth Observation Satellites

  • India’s first private constellation of Earth Observation (EO) Satellites will be built by a consortium led by Google-backed PixxelSpace. It also includes Piersight Space, Satsure Analytics India and Dhruva Space. 
  • The consortium will invest more than ₹1,200 crore over the next five years to launch a constellation of 12 EO satellites. 
  • The 12 EO satellite constellation will be entirely designed, manufactured, and operated in India. The constellation will be deployed in a phased manner over the next four years. 
  • The satellites will be equipped with panchromatic, multispectral, hyperspectral and microwave synthetic aperture radar (SAR) sensors.
  • Applications: Deliver analysis-ready data and value-added services for applications in:
    • Climate Change Monitoring
    • Disaster Management 
    • Agriculture
    • Infrastructure and Urban Planning
    • Marine Surveillance 
    • National Security 

Under the PPP framework, the government will provide strategic, technical and policy support, while the consortium will own and operate the EO system, including satellite manufacturing, launches from Indian soil, ground infrastructure and commercialisation of data services.

Significance: 

  • Demonstrates the capability of Indian private space companies to lead largescale, technologically advanced and commercially viable space missions that serve both national and global markets.
  • Advance world-class space-tech capability that will deliver analysis-ready data and value-added services to serve India, as well as the whole planet. 
  • Enhance India’s data sovereignty, reduce dependence on foreign imagery and ensure that all satellites are manufactured domestically, launched on Indian rockets and controlled from within the country.  

The project is also expected to create thousands of high-skill jobs and contribute to India’s target of growing its space economy from $8.4 billion in 2022 to $44 billion by 2033.

Also Read: What is Synthetic Aperture Radar? 

NASA to shut down Orbiting Carbon Observatories 

Context: The US administration has asked the National Aeronautics and Space Administration (NASA) to prepare to shut down Orbiting Carbon Observatories (two major satellites) that monitor atmospheric Carbon dioxide (CO2) and crop health.

The missions, still working perfectly, are being terminated to align with the US budget priorities.

Relevance of the Topic: Prelims: Key facts about Orbiting Carbon Observatories; Carbon dioxide. 

Orbiting Carbon Observatories

  • OCOs are a series of dedicated Earth remote sensing satellites designed specifically to observe atmospheric CO2 from space to better understand the characteristics of climate change. The two OCOs include: OCO-2 (launched in 2014) and OCO-3 (2019). 
  • Function: The satellites:
    • measure atmospheric CO2 and can also locate its sources and sinks. 
    • track crops and crop-growing seasons by measuring the glow that plants emit when they photosynthesise.
  • OCO-3 and OCO-2 do the same function, but they provide different perspectives to scientists.
    • OCO-2 flies around Earth in a sun-synchronous polar orbit which allows it to see any given location at the same time of day. 
    • OCO-3 flies aboard the International Space Station (ISS) which orbits Earth every 90 minutes. It can observe a location at many different times of day, and add to the dataset of its predecessor mission.

The US government now plans to shut down both OCO-2 and OCO-3 satellites. The satellites are more sensitive and accurate than any other mission operating or planned, in the world. 

Significance of the OCO Missions

Before the launch of the OCOs, scientists measured atmospheric CO2 mainly through instruments placed at various locations on the Earth’s surface. However, this did not provide them information about the whole planet. 

  • Provide a range of Data: OCOs have the ability to monitor crop health. NASA and other agencies have used the data to create high-resolution maps of plant growth around the world. The data generated by OCOs is used:
    • For CO2 measurement
    • To forecast and track crop yields and drought conditions
    • For drought monitoring
    • Forest mapping
    • To assess emission reduction efforts, and to develop effective strategies to tackle climate change. 
  • Advance scientific knowledge: OCOs have advanced scientific knowledge by paving the way for some surprising discoveries. For instance:
    • For decades, it was believed that tropical rainforests functioned as the lungs of the planet by clearing out vast quantities of CO2 from the atmosphere. However, data from OCO-2 revealed that boreal forests (also known as taiga), the coniferous forests in the higher latitudes of the northern hemisphere, play a significant role in the absorption of CO2.
    • The data showed how natural carbon sinks such as forests could become carbon emitters due to drought or deforestation.

About Carbon dioxide

  • Carbon dioxide, a colourless gas, is one of the most important greenhouse gases linked to global warming. It is a minor component of Earth’s atmosphere (about 3 volumes in 10,000).
  • Sources of Emission:
    • Natural: Respiration, decomposition of living animals, fermentation, emitted from oceans and other natural bodies of water, volcanoes, forest fires, and carbonate rocks.
    • Anthropogenic: Transportation, power and heat generation, chemical and petrochemical production, manufacturing, agriculture, food production. 
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Global Warming Potential:

  • GWP describes how much impact a gas will have on atmospheric warming over a period of time compared to carbon dioxide. Each greenhouse gas has a different atmospheric warming impact, and some gases remain in the atmosphere for longer than others. 
  • Carbon dioxide (CO2) has the lowest global warming potential, is the most abundant and lasts for thousands of years, so it is used as the baseline. 

NASA-ISRO Synthetic Aperture Radar

Context: The NASA-ISRO Synthetic Aperture Radar (NISAR) satellite was successfully launched on 30th July 2025 from the Satish Dhawan Space Centre at Sriharikota in Andhra Pradesh.

The Geosynchronous Satellite Launch Vehicle (GSLV-F16) successfully lifted and precisely injected the NISAR satellite weighing 2,392 kg into its intended sun-synchronous orbit.

Relevance of the Topic: Prelims: Key facts about NASA-ISRO Synthetic Aperture Radar (NISAR) Mission.

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About NISAR: 

  • NISAR is a Low Earth Orbit (LEO) observatory which will be placed in sun-synchronous orbit at an altitude of 747 km and an orbit inclination of 98.4°. 
  • It is a joint project between NASA and the Indian Space Research Organization (ISRO) to develop and launch a radar imaging satellite. The satellite will be the first to use dual frequencies.
  • Duration: Baseline mission duration of three years. 
  • Estimated Mission Cost: $1.5 billion.
  • The Earth observation satellite is capable of penetrating cloud cover and operating day and night regardless of the weather conditions, expected to revolutionise earth-observing capability. NISAR will observe nearly all the planet’s land and ice surfaces twice every 12 days. 
  • The 2,800 kilograms satellite consists of both L-band and S-band synthetic aperture radar (SAR) instruments, which makes it a dual-frequency imaging radar satellite.
    • L-band SAR operates at a frequency of around 1 to 2 GHz. The lower frequency (higher wavelength) of L-band SAR allows it to penetrate through vegetation and soil, making it useful for monitoring changes in forest cover, soil moisture etc. 
    • S-band SAR operates at a frequency of around 2 to 4 GHz. S-band SAR has a higher resolution than L-band SAR and is typically used for applications where higher resolution is required, such as monitoring changes in urban areas or coastal zones.

Significance:

  • NISAR will observe natural processes and changes in earth’s complex ecosystems.
    • Study Earth’s dynamic land and ice surfaces in greater detail and observe subtle changes in Earth’s surfaces. E.g., Track flow rates of glaciers and ice sheets, landslide-prone areas and changes in the coastline etc.
    • Spot warning signs of natural disasters, such as earthquakes, tsunamis, volcanoes and landslides.
    • Measure groundwater levels, agricultural mapping, vegetation biomass, natural resource mapping and monitor Earth’s forest and agricultural regions to improve understanding of carbon exchange. 

Valuable Lessons from Axiom-4 Mission

Context: The safe return of Group Captain Shubhanshu Shukla from the International Space Station as part of the Axiom-4 Mission, where he was the pilot among the four-member crew, marks a watershed moment for India’s space programme. 

Relevance of the Topic:Prelims: Key facts about Axiom-4 Mission. Mains: Significance of Axiom-4 Mission. 

Axiom-4 Mission

  • Axiom-4 Mission is a private spaceflight organised by Axiom Space launched aboard the SpaceX Dragon spacecraft in June 2025. 
  • The crew spent 18 days aboard the International Space Station (ISS) and conducted various experiments in the microgravity environment. 
  • The mission was conducted in collaboration with NASA, Axiom Space, ESA, and other international partners.

Successful Homecoming: 

  • Axiom-4 Mission returned to Earth with their SpaceX Dragon capsule splashing down off the San Diego coast in the US. 
  • The astronauts will undergo a rehabilitation programme for about a week under the supervision of flight surgeons to help him adapt back to gravity.
  • The crew completed 320 orbits of earth. They also completed over 60 research activities. 
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Valuable Lessons from Axiom-4 Mission

  • Invaluable lessons for Gaganyaan Mission: Group Captain Shukla of IAF is selected as one of the astronauts on India’s Gaganyaan Mission. The mission provides an invaluable blueprint for streamlining complex operational flows in the upcoming Gaganyaan Mission. This includes-
    • Pre-flight preparations and launch sequences to in-orbit activities, docking procedures, and the critical re-entry and recovery phases. 
    • Intricacies of communication protocols, real-time decision-making under pressure, and robust contingency planning. 
  • Blueprint for Astronaut Selection and Training: Participation in Axiom-4 Mission led to fairly detailed exposure of training procedures to Group Captain Shukla. This experience provides a rich case study in-
    • Crew training and preparation: Globally, commercial astronauts are from various professional backgrounds (not necessarily career military pilots) rigorously trained and seamlessly integrated into a complex mission profile. 
    • Refinement of India’s training methodologies and astronaut selection: This includes incorporating best practices for physiological adaptation to microgravity and psychological conditioning for isolation. Both simulation-based drills and real-time problem-solving scenarios can enhance the preparedness of Indian Vyomnauts.
  • Paves way for International Crewed Mission Coordination: While ISRO’s approach to space exploration and research has been largely national, the global landscape of human spaceflight is becoming increasingly collaborative and driven by the commercial sector. The mission showcases the efficiency and necessity of international collaboration, where diverse expertise works together towards shared objectives.
  • Private-sector Engagement in Space Sector:
    • Axiom-4’s reliance on established commercial launch and crew vehicles (like Space X’s Falcon 9 and Crew Dragon) highlights increasing reliability and capability of private-sector space transportation and collaboration. 
    • This could inspire India to explore strategic partnerships with the private sector in India and globally for certain sub-systems or specific commercial methodologies. 
    • This mission’s success (viability and profitability) can encourage more Indian companies to invest in space infrastructure, services, and human spaceflight support. This could lead to a thriving ecosystem of Indian suppliers, manufacturers, and service providers for future missions.
  • Encourages the Younger Generation to pursue STEM Education. 

As the global space community becomes more interconnected, Axiom-4 Mission highlights the benefits of pooling resources, expertise, and technological capabilities. 

The participation of one of its astronaut candidates in Axiom-4 will enrich Gaganyaan Mission in terms of planning and execution, and serve as a stepping stone in building operations infrastructure for future programs like commercial space flights and Bhartiya Antariksha Station.

Also Read: ISRO’s Experiments in Axiom-4 Mission

DRDO develops Photonic Radar

Context: Recently, the Defence Research and Development Organisation (DRDO) announced that it has developed a photonic radar system. India will likely become the fourth country after the US, China and Israel to induct these radars after key trials in late 2025. 

Relevance of the Topic: Prelims: Key facts related to Photonic Radar. 

What is a Radar?

  • Radar is short for Radio Detection and Ranging. 
  • Radar uses radio waves to determine the distance, velocity, and physical characteristics of objects around the device. 
  • A transmitter emits a radio frequency signal aimed at an object (E.g., a cloud) whose characteristics are to be ascertained. 
  • A part of the emitted signal is echoed by the object back to the device (reflected back), where a receiver tracks and analyses it to determine the features of the targeted object. 
image 24

What is a Photonic Radar?

  • Photonic Radar is a next-generation radar system that uses light-based (photonic) technology to generate, process and analyse radio-frequency (RF) signals. 
  • Conventional radars generate radio frequency (RF) signals using electronic components (like oscillators). However, such radars find it difficult to generate high-frequency signals beyond 40 GHz. 
  • Photonic radars use lasers and optical components (like optical fibres and modulators) to generate radio frequency (RF) signals and process signals using a technique called optical heterodyning. Photonic integrated circuits (PIC) used in the photonic radar can generate RF signals in the frequency range of 100 GHz to terahertz range, which is difficult to achieve using traditional electronic circuits.

The Photonic Radar System in India has been designed by the Electronics and Radar Development Establishment (LRDE), a DRDO lab known for creating advanced radars like Arudhra, Aslesha, and Uttam AESA.  

Superiority of Photonic Radar over Conventional radars:  

  • High Detection Ability: Photonic radars can spot objects that conventional radars miss, including stealth aircraft, drones, and even incoming hypersonic missiles.
  • Longer Range, Sharper Image and Lesser Noise:
    • Photonic radars can generate high bandwidth signals (the higher the bandwidth, the greater the resolution). 
    • It has a higher signal-to-noise ratio (noise emanates from the heat generated by electronic components in conventional radar) leading to sharper detection of the ‘echo’ from the target. 
    • As a result, the radars have longer range and the ability to map targets in high-resolution 3D.
  • Immune to Jamming: Photonic components are practically immune to electromagnetic jamming or electronic warfare tactics that often try to blind or confuse traditional radars. Additionally, Photonic radars are capable of frequency hopping- they keep changing their frequencies, which confuses the jammers.
  • Light Weight: Photonic components do not have copper and are lighter. This enables the fitting of these small, lighter radar systems in satellites, swarms of drones and fighter jets. 

Potential Applications of Photonic Radar: 

  • Military Applications:
    • With its ultra-wide bandwidth, low signal noise, and high precision, the photonic radar may be able to spot threats early.
    • The radar system can be integrated with India's existing air defence infrastructure- such as Akashteer command and control system. Can be deployed on various platforms- including fighter jets (Su-30 MKI, Rafale, Tejas); mobile ground units for the Indian Army.
  • Medical Applications: Photonic radar could be used as a non-invasive way to monitor patient vital signs, such as breathing and heart rate. The device could fit onto a photonic chip that is small enough to incorporate into electronic devices like a smartphone.
  • Space Missions: Can be integrated into small satellites for deep-space tracking. 
  • Weather monitoring, high-resolution atmospheric observations & coastal surveillance. 

Associated Challenges: 

  • Gaining access to PICs: India lacks infrastructure to fabricate Photonic integrated circuits (PIC). 
  • Export Restrictions: In order for large-scale production of PICs, India will have to design the circuits and get them fabricated outside India. However, that is a humongous task given the export restrictions from the US; security risks in fabricating them from China. 
  • Material Constraints: Photonics utilise special materials, mainly indium phosphide and silicon photonics, which are hard to procure. Similarly, other components like tunable lasers and modulators are hard to procure. 

DRDO is preparing for extensive trials of the Radar in late 2025 to assess its effectiveness in diverse and challenging conditions. The technology strengthens India’s position in regional military balance and makes its defence systems much harder to bypass or fool.

New Emerging Radar Systems: 

Two radar systems under development promise to be better than photonic radars.

Quantum Radar: 

  • Quantum radar uses quantum technology for detection and imaging. The technology is still in the experimental stage. 
  • At the core of this technology is the production of a pair of entangled photons- sending one photon to the target, and then comparing it on reflection with the second photon; the difference will be used to analyse the location and characteristics of the target. 

Terahertz Radar: 

  • Terahertz radar operates in the electromagnetic spectrum between microwaves and infrared light (typically 0.1-10 THz) - where the signal oscillates a trillion times a second. The corresponding wavelength is about 0.3 mm. This will offer high resolution imaging. 

Also Read: What is Synthetic Aperture Radar? 

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