Astronomy & Space Technology

Astronomers discover 128 new Moons orbiting Saturn

Context: Recently, astronomers have located 128 new moons orbiting Saturn using the Canada France Hawaii telescope. Saturn now officially has 274 confirmed moons, the highest for any planet in the Solar System. Saturn is followed by Jupiter with 95 known moons. 

Relevance of the Topic:Prelims: Key facts about Saturn; Saturn’s Moons.

Key facts about Saturn

  • Saturn is the sixth planet from the Sun. It is the second-largest planet in our Solar System, after Jupiter.
  • Saturn is a gas giant dominated by hydrogen and helium. Its atmosphere contains hydrogen, helium, methane, ammonia, and other gases, giving it a yellowish-brown appearance. The planet is thought to have a rocky core. 
  • Saturn's average density is 0.69 g/cm³, making it the only planet less dense than water by about 30%. Its low density is due to its vast gaseous atmosphere. 
  • Saturn's rapid rotation gives it an oblate shape. It is flattened at the poles and bulging at the equator. Saturn's rings are made of ice, dust, and rock. 
  • Saturn orbits the Sun at an average distance of 9.59 astronomical units (AU), or roughly 1,434 million kilometers. The orbital period is about 29.45 Earth years.
  • Saturn is known for its large and intense storm systems, such as the Great White Spot. This massive storm occurs roughly once every Saturnian year (about 29 Earth years). These storms can last for months and cover vast areas. 

Saturn’s Important Moons

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Saturn has 274 moons recognised by the International Astronomical Union.

  • Titan: 
    • Titan is Saturn's largest moon and is one of the most Earth-like bodies in the Solar System. Titan is larger (though less massive) than Mercury.
    • It is the only moon in the Solar System with a dense atmosphere.
    • Nitrogen and methane extend around the moon 10 times as far into space as Earth's atmosphere, sometimes falling to Titan's surface as methane rain.
    • It has liquid hydrocarbon lakes in the polar region. Cassini-Huygens spacecraft landed on Titan in 2005. 
  • Enceladus: 
    • Enceladus is an icy Saturnian moon that has a liquid ocean of water beneath its crust, making it one of the most promising places to look for signs of life beyond Earth. 
    • It has the whitest, most reflective surface in the solar system. 
    • The strange moon spews its ocean out into space. In 2005, NASA's Cassini spacecraft found icy water particles gushing from the surface at approximately 400 meters per second. 
    • Nanograins of silica have been found in Saturn's E-ring, which suggests the presence of hydrothermal vents within Enceladus' ocean. 

Also Read: Age of Saturn’s Rings  

Parker Solar Probe’s closest approach to Sun

Context: In March 2025, NASA's Parker Solar Probe performed its latest flyby, passing within 8 million miles (6.1 million kilometers) of the surface of the sun. Flying at a record-breaking speed of 692,000 kilometers per hour, it shattered its own previous record made in December last year.

Relevance of the topic: Prelims: Key facts about the Parker Solar Probe. 

Major Highlights:

  • On 24 December 2024, the Parker Solar probe made its closest approach to the Sun, coming to a distance of 6.1 million km (0.04 AU) from the surface. 
  • Its beacon signal was received on 26 December, showing that it had survived the passage through the corona (survived the heat).
  • The spacecraft has become the closest ever artificial object to the Sun.
  • Significance: The flyby is a major step forward in understanding the Sun and its impact on our solar system.
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About Parker Solar Probe

  • The Parker Solar Probe was launched in 2018 to make observations of the Sun's outer corona.
  • Mission of: National Aeronautics and Space Administration (NASA).
  • Aim: 
    • Trace the flow of energy that heats the solar corona and accelerates the solar wind.
    • Determine the structure and dynamics of the plasma and magnetic fields.
    • Explore mechanisms that accelerate and transport energetic particles.
  • The spacecraft has become the closest ever artificial object to the Sun. It has circled gradually closer to the sun, flying past Venus in order to use the planet’s gravity to move it into a tighter orbit.
  • The spacecraft's systems are protected from the extreme heat and radiation near the Sun by a solar shield. 
    • The solar shield is mounted on the Sun-facing side of the spacecraft.
    • It is made from reinforced carbon–carbon composite with a carbon foam core.
    • It is designed to withstand temperatures outside the spacecraft of over 1370 °C.

​The mission represents a huge step forward in our understanding of the Sun. Scientists are hopeful that the information it provides will help us learn not only about our star but also about how other stars in the universe work.

GSAT-18

Context: Public Accounts Committee has raised concerns over the underutilisation of six transponders in GSAT-18. It has recommended that the Department of Space be more economically prudent while planning future space projects.

Relevance of the Topic: Prelims: GSAT-18; Communication satellites. 

About GSAT-18: 

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  • GSAT-18 is a communication satellite launched by Indian Space Research Organisation (ISRO) in 2016.
  • Launched using: Heavy-duty Ariane-5 rocket from Kourou, French Guiana.
  • Weight: 3404 kg (Ariane-5 was used because GSLV Mk-III was not operational, at that time)
  • Mission Life: 15 years (until 2032)
  • Location: Geostationary Orbit
  • Transponders: 48 communication transponders (Extended C-band, Normal C-band, and Ku-band)
  • Services provided: DTH broadcasting, Telecommunications, VSAT, broadband internet services.
  • It strengthens ISRO’s operational fleet of 14 telecommunication satellites, and ensures continuity of communication services by replacing ageing satellites.

Highlights of the PAC report

  • Economic viability concern: Presently, six transponders in GSAT are kept idle till the year 2027 (would be utilised from 2027-2032). The non-ulilisation of six transponders for 11 years (since 2016) raises concerns about the cost-effectiveness of the mission.
  • Loss of revenue: This non-utilisation has led to a financial loss of ₹117 crore.

The Department of Space has clarified that the GSAT-18’s extra transponders acted as a backup in case of any failure in transponders, to provide continuity in services. 

ESA retires Gaia Space Observatory

Context: The European Space Agency (ESA) has shut down its Gaia Space Observatory in March 2025. Gaia used its thrusters for the final time to slowly drift into its “retirement orbit” around the Sun.

Relevance of the Topic: Prelims: Key facts about Gaia Space Observatory. 

About Gaia Space Observatory

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  • GAIA (Global Astrometric Interferometer for Astrophysics) is a space astrometry mission of ESA. 
  • Launched: 2013
  • Location: Lagrange point 2 (around 1.5 million kilometres ‘behind’ the Earth, when viewed from the Sun)
  • Aim: To create the most precise, three-dimensional map of the Milky Way galaxy. 
  • Gaia has tracked over 2 billion stars and space objects. The spacecraft is fitted with three instruments – an astrometer, a photometer and a spectrometer – that help interpret the location and motion of stars and other objects.
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  • Lagrange points are positions in a moving two-body system where the combined gravitational forces of two large bodies (such as the Sun and Earth or Earth and the Moon) acting on a third body of smaller mass cancel each other out.
  • While absolute neutralisation is not achievable due to the influence of other celestial bodies (such as Moon, Mars, and Venus etc.), they provide a stable position where a spacecraft may be "parked" to make observations.

There are five Lagrange points located along the line connecting the two larger celestial bodies.  

  • L1 point: Located roughly 1.5 million kilometres from Earth. It provides an uninterrupted view of the Sun (the satellite can view the Sun without eclipses). 
  • L2 point: Provides an unobstructed view of the Universe and is stable enough for long-duration observations. Location for space-based observatories (James Webb Space Telescope). 
  • L3 point: Lies behind the Sun, opposite to Earth. Offers the potential to observe the far side of the Sun. Possible location for a future space-based observatory. 
  • L4 and L5 point: Stable locations but are relatively farther from Earth than L1.

Achievements of GAIA

  • Data allowed recreation of a precise 3D map of the Milky Way galaxy; Help understand the shape of our galaxy. 
  • Uncovered a new kind of black hole – including one close to the Earth. Black holes were previously discovered by light emitted by materials falling in, but  those discovered by Gaia can only be detected by their gravitational effects.
  • Detected over 1,50,000 asteroids and projected their orbits, including those that may pose a threat to the Earth in the future.

Martian dust may pose Health Risks to Astronauts

Context: A recent study carried out by the US researchers has found that toxic dust on Mars would make a future mission to the red planet extremely hazardous for astronauts. 

Relevance of the Topic:Prelims: Key facts about Mars; Mars Missions. 

Major Highlights of the Report

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  • Fine dust: The size of a Martian dust particle is quite small (it is about 4% the width of a human hair). The fine particles of the dust could penetrate deep into the lungs and enter the bloodstream and cause respiratory issues. 
  • Toxic elements in Martian dust: Silica, gypsum, perchlorates, chromium, arsenic and nanophase iron oxides. The impact of these toxins could be more significant due to microgravity and radiation on Mars.
  • Dust storms: Every Martian year (which lasts ~687 Earth days), the planet witnesses regional dust storms. Every three Martian years, these storms grow into planet-encircling dust storms.

The use of air filters, self-cleaning space suits and electrostatic repulsion devices (remove dust particles) can limit exposure to dust. 

Facts about Mars

  • Fourth planet from the Sun and second-smallest planet in the Solar System. Mars is about half the size of Earth. 
  • Similarity to Earth (Orbit and Rotation):
    • Mars rotates every 24.6 hours, which is very similar to one day on Earth (23.9 hours).
    • Mars' axis of rotation is tilted 25 degrees with respect to the plane of its orbit around the Sun. Earth’s axial tilt is 23.4 degrees.
    • Like Earth, Mars has distinct seasons, but they last longer than seasons on Earth since Mars takes longer to orbit the Sun.
  • Red Planet: Mars looks reddish due to oxidation or rusting of iron in rocks, and dust of Mars.
  • Mars has a thin atmosphere made up mostly of carbon dioxide, nitrogen and argon gases.
  • Mars has no magnetic field, but certain areas of Martian crust in the southern hemisphere are highly magnetised, indicating traces of a magnetic field.
  • Mars has two small moons, Phobos and Deimos, that may be captured asteroids.
  • Mars has the largest volcano in the solar system i.e., Olympus Mons. It is 3 times taller than Earth's Mt. Everest.

Martian Missions: 

  • The Soviet Union in 1971 became the first country to carry out a Mars landing, Mars-3. The second country to reach Mars’s surface is the USA. 
  • India’s Mars Orbiter Mission (Mangalyaan) was launched from Satish Dhawan Space Centre in Andhra Pradesh by ISRO in 2013.

Reasons for fascination with Mars:

  • Mars has several Earth-like features– such as clouds, polar ice caps, volcanoes, and seasonal weather patterns. 
  • Life may have evolved on Mars in the past. Conditions on early Mars were very similar to that of Earth. It was once warm enough to allow water to flow through it. It had a thick atmosphere, which enabled stability of water on the surface of Mars. 
  • Mars is the only planet that humans can visit or inhabit in the long term. Mars is comparatively hospitable in terms of temperature, with an approximate range between 20 degrees Celsius at Equator to minus 125 degrees C at poles.

However, no human has set foot on Mars because the atmosphere on Mars is very thin, consisting of mostly carbon dioxide with no breathable oxygen, making it difficult for astronauts to survive there.  

NASA Astronauts return to Earth after 9 months

Context: American astronauts Sunita Williams and Butch Wilmore have returned to Earth onboard SpaceX Dragon spacecraft after the longest ever unscheduled stay in the International Space Station (ISS). They splashed down off the coast of Florida, US after a journey of 17 hours from the ISS.

Relevance of the Topic:Prelims: Key facts about Boeing's CST-100 Starliner; SpaceX's Crew Dragon spacecraft; International Space Station; Impacts of Space travel. 

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Major Highlights

  • In June 2024, the NASA astronauts embarked on a mission to ISS, aboard Boeing's Starliner spacecraft, initially planned for an eight-day duration.
  • The astronauts aimed to validate the capability of Boeing’s CST-100 Starliner in taking crewed missions to the ISS.  However, Starliner spacecraft faced technical issues, and their stay was extended to approximately nine months (286 days).  

Causes of the delay

  • Technical Malfunctions: During the mission, Boeing Starliner spacecraft experienced several technical problems, including thruster malfunctions and Helium leaks in the thrusters. 
  • Alternative return vehicle: Given the unresolved technical issues with Starliner, NASA decided that the astronauts would return to Earth aboard SpaceX's Crew Dragon spacecraft, scheduled for February 2025.
    • Crew Dragon is the only U.S. spacecraft capable of flying people in orbit (conducting crewed orbital flights). 
    • Boeing Starliner (also known as CST-100) is a spacecraft manufactured by Boeing under a contract with NASA's Commercial Crew Development program. It hoped to compete with the SpaceX Crew Dragon capsule. 

Astronauts with most days in Space: 

  • Russia's Oleg Kononenko has made five trips to space spending a total of 1111 days, on his last journey he returned to earth after 374 days.
  • Soviet Cosmonaut Valeri Polyakov holds the record- 438 days at the Mir space station between January 1994 and March 1995. 

Also Read: How does Space Travel affect the Health of an Astronaut? 

The impacts of being in space, especially for long periods of time, on the body are still being studied. Past studies showed that bone density and muscle quality deteriorated faster in space than on earth. Low gravity impacts brain fluids and may alter brain structure and increase risk of heart disease. 

ISRO undocks SpaDex satellites in first attempt

Context: The Indian Space Research Organisation (ISRO) has successfully accomplished the pivotal operation of undocking of SpaDex satellites in the very first attempt on March 13, 2025. 

Relevance of the Topic: Prelims: About Space Docking Experiment (SpaDex);  Space Docking & Undocking. 

SpaDex Undocking

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  • Undocking:
    • The undocking process culminated in the separation of the SDX-01 (Chaser) and SDX-02 (Target) satellites, which were launched on December 30, 2024, using Polar Satellite Launch Vehicle (PSLV)-C60 from the Satish Dhawan Space Centre in Sriharikota.
    • Earlier, these two satellites were successfully docked (joined together) in January.
    • The undocking operation was conducted in a 460 km circular orbit with a 45-degree inclination.
  • Satellite Status: Post-undocking, the satellites are orbiting independently, and their health remains normal. The operations were monitored through ground stations located in Bengaluru, Lucknow, and Mauritius.

Significance:

  • Successful completion of both docking and undocking makes India the fourth country in the world — after the United States, Russia, and China — to have this capability.
  • It paves the way for smooth conduct of ambitious future missions including the Bharatiya Antriksha Station, Chandrayaan 4 and Gaganyaan.

Also Read: ISRO achieves Space Docking: SpaDeX Mission 

Rising Space Debris: Threats & Mitigation Efforts

Context: A 500-kg metal object, suspected to be space debris, crashed in Kenya, raising concerns over accountability and legal gaps in space governance.

Relevance of the topic:

Prelims: Space Debris- Current affairs, Global laws

Mains: Space Debris- Threats, Legal framework, Way Forward

What is Space Debris?

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  • Space debris refers to man-made objects in Earth's orbit that no longer serve a useful purpose.
  • This includes defunct satellites, spent rocket stages, and fragments of debris from collisions or other events.
  • Types of Space debris:
    • Large debris: Defunct satellites, rocket boosters, fuel tanks that survive reentry.
    • Small debris: Fragments from satellite collisions, disintegrated spacecraft.
    • Microscopic debris: Paint flakes, dust particles, and metal fragments from damaged satellites.

Potential Hazard from Space Debris

  • Threat for operational satellites:
    • The floating space debris is a potential hazard for operational satellites and colliding with them can leave the satellites dysfunctional.
    • This overpopulation of space with objects and debris is referred to as Kessler Syndrome.
  • Reduction of orbital slots: The accumulation of space debris in specific orbital regions can limit the availability of desirable orbital slots for future missions.
  • Impacts Space situational awareness: The increasing amount of space debris makes it more challenging for satellite operators and space agencies to accurately track and predict the orbits of objects in space.
  • Risks from incidents of uncontrolled re-entries on Earth: 
    • Kenya (2024): A 500 kg metal object, suspected to be a rocket separation ring, crashed in Makueni County.
    • Poland (2024): Debris from a SpaceX Falcon 9 rocket landed without prior warning.
    • China (2024): Long March 5B rocket core stage reentered uncontrolled, narrowly missing populated areas.
    • Australia (2022): A SpaceX Dragon capsule fragment crashed in a remote area.
  • Rising Risk from Satellite Mega-Constellations:
    • Companies like SpaceX Starlink, Amazon Kuiper, and Eutelsat OneWeb plan to add over 100,000 satellites by 2030.
    • Many older satellites lack de-orbiting plans, increasing the risk of collisions and debris.
    • The UN guidelines recommend deorbiting within 25 years, but compliance is only 30%.
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Legal Framework for Space Debris

  • Lack of a clear definition:
    • No universally accepted legal definition of space debris exists.
    • The UN Committee on the Peaceful Uses of Outer Space (COPUOS) defines space debris as non-functional man-made objects in orbit or reentering the atmosphere.
  • International Space Laws and Liability:
    • Outer Space Treaty (1967): Holds states responsible for all national space activities.
    • Liability Convention (1972):
      • Introduced absolute liability (requires no proof of negligence) for damage caused by space objects on Earth. 
      • However, enforcement is weak, and compensation is often inadequate.
      • Example: Canada received only $3 million out of the $6 million clean-up cost after the Cosmos 954 satellite crash (1978).

India’s Initiatives for Space Debris Management: 

  • ISRO System for Safe & Sustainable Operations Management (IS4OM) (2022): Monitors space objects that pose collision threats to Indian satellites.
  • Project Netra (Network for Space Object Tracking and Analysis): Detects, tracks, and catalogs debris as small as 10 cm up to a range of 3,400 km.
  • Collision Avoidance Manoeuvres: ISRO performed 21 collision avoidance manoeuvres in 2022 to prevent space debris impact.
  • Space Situational Awareness Control Centre (2020): Functions as India’s central hub for monitoring and managing space traffic.
  • International Collaboration: India actively engages in UN discussions on space debris mitigation and sustainability.

Challenges in Space Debris Governance: 

  • Difficulty in attributing debris to its source: While tracking systems exist, older or highly fragmented debris is difficult to trace.
  • No oversight once control is lost:
    • Countries like the U.S. argue that responsibility ends once a space object is no longer actively controlled.
    • E.g., The FAA stated it had no responsibility after losing contact with the Falcon 9 rocket.
  • Lack of binding regulations for controlled reentries:
    • No legal requirement for countries to ensure controlled reentries.
    • E.g., China’s Long March 5B rocket has had four uncontrolled reentries since 2020.

Way Forward

  • Enforceable International laws: 
    • COPUOS must push for binding regulations on controlled reentries.
    • Penalties should be imposed on non-compliant states.
  • National-level policy reforms:
    • Governments should mandate debris mitigation for launch licenses.
    • Companies should be required to use controlled reentry mechanisms.
  • Improved tracking systems:
    • Expansion of space surveillance systems like the U.S. Space Fence.
    • More advanced prediction models for reentries.
  • Sustainable space practices:
    • Promotion of debris-neutral technologies and reusable rockets.
    • Mandatory use of graveyard orbits for defunct satellites.
  • Modernising 1972 Liability Convention: Creation of an international tribunal with binding enforcement powers.

ISRO conducts crucial test for Semi-Cryogenic Engine

Context: Recently, Indian Space Research Organisation (ISRO) has successfully conducted the hot test on a semi-cryogenic engine (SE2000). 

Relevance of the Topic: Prelims: Key Facts about Semi-cryogenic Engine; Cryogenic Engine.

Hot Test (PHTA) on Semi-cryogenic Engine

  • ISRO is developing a semi-cryogenic engine that uses a Liquid Oxygen and Kerosene-based propulsion system that offers an enhanced thrust of 2,000 kiloNewton (kN).
    • Power Head Test Article (PHTA) is the first hardware test for the development of semi-cryogenic engines.
    • The test involves performing a hot-firing for an extremely brief duration of not more than 4.5 seconds.
    • PHTA is done to validate the integrated performance of some of the engine’s critical subsystems, such as the gas generator, turbo pumps, pre-burner and control components.
  • The success of the test brings ISRO a step closer towards enhancing the payload capability of LVM3 and for future launch vehicles.
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Propulsion System: 

  • The propulsion system gives the rocket power to lift off from the Earth, across the dense atmosphere and later reach its destination. 
  • The selection of an appropriate propellant system is based on the thrust required, reusability, cost and core competency. 
  • ISRO has been using environment-friendly and green propellants like Liquid Oxygen (LOX), Liquid Hydrogen (LH2) and LOX-kerosene-based propulsion systems.

Advantage of Semi-cryogenic Engine over Cryogenic Engine: 

  • The cryogenic engine uses liquid oxygen and liquid hydrogen.
    • Handling liquid hydrogen is challenging, given that it needs to be stored at minus 253 degrees Celsius and it is highly inflammable. 
  • A semi-cryogenic engine uses a liquid oxygen – kerosene combination, where kerosene is readily storable.
    • This combination offers advantages like high-density impulse (with respect to cryogenic engines), is less toxic (with respect to fuel storage) and is cost-effective.

Upcoming Developments by ISRO: 

  • Upgradation of LVM3: ISRO is working towards improving the performance of Launch Vehicle Mk III (LVM3).
    • LVM3 will be equipped with the C32 cryogenic upper stage for many of its future space missions.
      • C32 is an upgraded version of the C25 stage currently used in LVM3.
      • With C32 in the upper stage, the payload capacity (carriage) will increase by 25%. 
    • ISRO is working to increase LVM3’s launch capacity from 4 tonnes to 5.1 tonnes at Geosynchronous Transfer Orbit, without increasing the cost. 

Also Read: ISRO’s Satellite Launch Vehicles 

  • Development of NGLV: 
    • Next Generation Launch Vehicle is a new generation, human-rated launch vehicle, offering both high payload capability and reusability. 
    • With a reusable first stage, it offers a maximum payload capability of 30 tons to the Low Earth Orbit.
    • The first and second stages will use LOX engines and the upper stage will be a cryogenic stage. 

Also Read: ISRO’s Next Generation Launch Vehicle 

NASA’s PUNCH Mission

Context: The National Aeronautics and Space Administration (NASA) is set to launch its latest solar mission PUNCH (Polarimeter to Unify the Corona and Heliosphere) from Vandenberg Space Force Base in California on March 6, 2025.

Relevance of the Topic: Prelims: Key Facts about NASA’s PUNCH Mission; Solar Cycle; Terms related to Sun.

PUNCH Mission

  • PUNCH (Polarimeter to Unify the Corona and Heliosphere) is a solar mission that will study the solar corona (the outermost layer of the Sun’s atmosphere). 
  • Initiative of: National Aeronautics and Space Administration
  • Aim: To better understand the solar atmosphere and solar wind.
  • Launched using: Falcon-9 rocket from California, the US. 

Key Features: 

  • PUNCH consists of Four identical suitcase-sized satellites in low Earth orbit (LEO) that will continuously image the Sun’s corona (outer atmosphere) and provide origins of solar flares, etc.
  • It is the first mission that uses polarisation of light to study the Sun's corona in 3D. 
    • When particles (such as electrons) scatter sunlight, the waves of light become aligned in a particular direction (this is polarized light). 
    • PUNCH will measure the light using polarising filters similar to polarising sunglasses, allowing scientists to make a 3D map of features PUNCH sees throughout the corona and inner solar system. 

Polarisation of Light

  • Light travels in the form of transverse electromagnetic waves. The light emitted by sources like the sun, bulb, candle etc. has vibrations in several planes (oscillates in all directions), and it is called unpolarised light.
  • Polarisation is the phenomenon of restricting the vibration of light waves to one specific direction/plane. E.g., Polarised sunglasses have a special filter that allows only light with a specific polarisation direction to pass through, which helps to reduce glare and improve visibility by blocking unwanted polarisations.
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Recent Solar Missions

  • PUNCH (Polarimeter to Unify the Corona and Heliosphere) is the third major solar mission to be launched in the past 18 months. Since September 2023, two solar missions have been launched. These are:

1. Aditya L1 (India):

  • Launched in September 2023. 
  • Initiative of: Indian Space Research Organisation
  • Location: Lagrange point 1 (located at a distance of about 1.5 million km from the Earth).
  • India’s first solar mission. It is designed to study solar flares and solar winds, measure low-intensity magnetic fields and solar soft X-ray flux, etc.

Read More: Aditya L1 Mission  

2. Proba-3 (European Space Agency): 

  • Launched in December, 2024. 
  • Initiative of: European Space Agency
  • Launched by: Indian Space Research Organisation.
  • Proba-3 aims to study the Sun's corona (the outer layer of the Sun’s atmosphere) and solar winds.

Read More: Proba-3 Mission  

What is the Solar Cycle?

  • Solar cycle is the cycle that the Sun’s magnetic field goes through approximately every 11 years.
    • Every 11 years or so, the Sun's magnetic field completely flips, i.e., the Sun's North and South poles switch places. 
    • Then, after another 11 years, the Sun’s north and south poles flip back again. This periodic change is known as the solar cycle.
  • The solar cycle affects activity on the surface of the Sun, such as sunspots which are caused by the Sun's magnetic fields.
    • Solar Minimum: Beginning of a solar cycle when the Sun has the least sunspots. Over time, solar activity and the number of sunspots increases. 
    • Solar Maximum: Middle of the solar cycle when the Sun has the most sunspots. As the cycle ends, it fades back to the solar minimum and then a new cycle begins. 
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Why do space agencies want to make the most of Solar Maximum?

  • According to the National Oceanic and Atmospheric Administration (NOAA) and NASA, the Sun has entered the solar maximum phase around October 2024, which could continue for another year.
  • Solar maximum is the best possible window available for physicists to both launch and observe the sun, as the solar activities peak during this period. Giant eruptions on the Sun, such as solar flares and coronal mass ejections increase during the solar maximum. 
  • The next possible intense solar activity will be around 2035-2036.
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Key Terminology related to Sun

TermsDescription
Solar Magnetic Field Complex magnetic field that exists due to the constant movement of electrically charged particles within the Sun (in its interior).
Solar WindContinuous flow of charged particles from the Sun. Created by the outward expansion of plasma from the Sun’s surface (plasma is continually heated to the point that the Sun’s gravity cannot hold it further). It travels along the Sun’s magnetic field lines.  
Sunspots Temporary spots (small, dark and cooler areas) on the Sun’s Photosphere, where magnetic fields are particularly strong. Solar flares tend to originate from regions that contain sunspots. The number of sunspots can indicate the likelihood of solar flare eruption.
Solar Flares Sudden and intense burst of solar energy from the Solar atmosphere. It is caused by the release of magnetic energy stored in the Solar atmosphere. The energy is released in the form of light/radiation and high energy charged particles. 
Coronal Mass Ejection Large-scale expulsion of plasma and magnetic field from the sun’s outer atmosphere or corona into space.

Private lunar lander Blue Ghost soft-lands on Moon

Context: Firefly Aerospace's uncrewed Blue Ghost lunar lander has successfully soft-landed on the Moon's Mare Crisium region. This makes Firefly Aerospace only the second private-sector company ever to complete such a feat.

Relevance of the Topic: Prelims: Key Facts about Blue Ghost Mission 1; Axiom Mission; Polaris Dawn Mission; Odysseus. 

Firefly's Blue Ghost Mission 1

  • Firefly's Blue Ghost Mission 1 (Ghost Riders in the Sky) is a part of NASA's Commercial Lunar Payload Services (CLPS) initiative.
  • Initiative of: Firefly Aerospace (US-based private space company)
  • Launched using SpaceX Falcon 9 rocket on January 15, 2025.
  • Soft-landing on Moon: 2 March, 2025.
  • Landing site: Mare Crisium region- a prominent lunar basin visible from Earth.
  • Milestones: 
    • Firefly becomes the second private firm to achieve a moon landing.
    • First commercial mission to achieve a fully successful soft-landing on the Moon.
  • Payloads:
    • Blue Ghost carried 10 scientific and technological payloads, including NASA instruments designed to study lunar dust, radiation and surface materials.
    • The lander will operate for approximately 14 Earth days, equivalent to one lunar day.
  • Firefly plans two additional Blue Ghost missions in 2026 and 2028.
  • Note: NASA’s CLPS initiative aims to conduct science on the Moon for the benefit of all and improve understanding of the lunar environment. 
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Important Private Space Exploration Missions: 

1. Axiom Mission: 

  • Privately-funded and operated crewed mission to the International Space Station (ISS).
  • Launched by: Axiom Space
  • Utilised: SpaceX Crew Dragon spacecraft; Falcon 9 rocket.
  • Launched from: NASA’s Kennedy Space Center in Florida, the US. 
  • Axiom Mission 1:
    • World’s first commercially crewed private spaceflight to the ISS. 
    • Launched in April 2022 for a 17-day stay.
  • Axiom Mission 2: Launched in 2023, spent 8 days in orbit.
  • Axiom Mission 3: Launched in 2024, stayed docked for 18 days.
  • Axiom Mission 4: To be launched in 2025.
    • Shubhanshu Shukla, an Indian Air Force (IAF) officer and ISRO astronaut, has been named the pilot for Axiom Mission 4.

2. Polaris Dawn Mission:

  • Private human spaceflight mission launched in September 2024. 
  • Utilised: SpaceX Crew Dragon spacecraft; Falcon 9 rocket.
    • Crew Dragon is a spacecraft developed and manufactured by SpaceX as part of NASA's Commercial Crew Program. It can carry up to seven astronauts. For NASA missions, it typically carries four astronauts and some cargo.
    • SpaceX Falcon 9 rocket is a partially reusable two-stage rocket that can propel both satellites and astronauts into a variety of orbits.
  • The crewed mission consisted of four astronauts.
    • Five-day spaceflight mission. The crew travelled further into space than any humans since the Apollo 17 mission (1972). 
    • Passed through parts of the Van Allen radiation belt to study the health effects of space radiation and spaceflight on the human body. 
    • The crew performed the first commercial spacewalk.

3. Odysseus: 

  • First commercial spacecraft to reach the Moon in February 2024.
  • Initiative of: US-based Intuitive Machines. 
  • The mission was short-lived as the spacecraft hard-landed on the slope of a crater, and damaged onboard instruments.

The success underscores the growing role of private companies in space exploration as NASA and other space agencies increasingly rely on commercial partners to achieve scientific and technological breakthroughs. 

Upcoming Private Lunar Missions:

Following the successful landing of Blue Ghost lunar lander, the lunar surface is set to welcome two more missions shortly. 

  • Athena or IM-2: 
    • Second mission by Intuitive Machines (US private firm)
    • Launched aboard: SpaceX Falcon 9 rocket
    • Part of NASA's Commercial Lunar Payload Services (CLPS) initiative.
    • Supposed to land on March 6, 2025 in the relatively less-explored southern pole region of the Moon.
    • Athena carries a suite of scientific experiments, including:
      • a drill and mass spectrometer designed to explore lunar ice deposits near the Moon's south pole.
      • three robotic rovers and a compact flying 'hopper' that will be deployed post-landing. 
  • Hakuto-R Mission 2: 
    • Japanese mission by private firm ispace
    • Scheduled to land in May or June, 2025. 
    • Hakuto-R has a lander and a rover designed to explore the lunar surface and provide valuable insights into the Moon's geology and potential resources.
    • Hakuto-R’s first mission in 2023 had been unsuccessful.

As NASA works towards establishing a sustained human presence on the Moon, missions like Blue Ghost, Athena, and Hakuto-R2 are laying the groundwork by testing technologies and conducting scientific research that will be essential for future human missions. 

SUIT onboard Aditya-L1 captures Solar Flare

Context: The Solar Ultraviolet Imaging Telescope (SUIT) onboard Aditya-L1 (India’s first dedicated space-based solar mission) has captured the first-ever image of a solar flare ‘kernel’ in the lower solar atmosphere — the photosphere and chromosphere.

Relevance of the Topic: Prelims: Key Facts about Aditya-L1 Mission; Payloads on Aditya-L1 (like Solar Ultraviolet Imaging Telescope); Solar Flares.

Major Highlights:

  • The SUIT payload onboard Aditya-L1 observed an X6.3-class solar flare, which is one of the most intense categories of solar eruptions.
    • SUIT detected brightening in the Near Ultra Violet (NUV) wavelength range (200-400 nm) — a wavelength range never observed before in such greater detail. 
    • Revelation: 
      • Localised brightening captured in the lower solar atmosphere corresponds directly with an increase in the temperature of plasma in the solar corona at the top of the solar atmosphere.
      • These observations confirm that the energy released from the flare spreads through different layers of the Sun’s atmosphere.
  • Significance:
    • Enhance understanding of Sun’s explosive activity and its impact on Earth.
    • New insights into the complex physics responsible for massive solar explosions.
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Aditya-L1 Mission

  • Aditya-L1 is India's first solar mission dedicated to study the Sun.
  • Launched by: Indian Space Research Organisation in 2023. 
  • Location: Lagrange point 1 (located at a distance of about 1.5 million km from the Earth).
  • Mission:
    • To study the solar atmosphere, particularly the chromosphere and corona.
    • To observe solar magnetic storms and their impact on Earth's environment.
  • Payloads: It has seven payloads including Solar Ultraviolet Imaging Telescope (SUIT).
    • SUIT is designed to image the Sun in the 200-400 nanometre (nm) of the ultraviolet band. 
    • SUIT’s imager will continuously record the entire disk of the Sun through 11 filters. The images of these layers could help improve our understanding of the Sun’s immediate atmosphere.

Read More: Aditya L1 Mission 

What are Solar Flares?

  • A solar flare is a sudden and intense burst of solar energy from the Solar atmosphere. 
  • The phenomenon is caused by the release of magnetic energy stored in the Solar atmosphere.
    • The Sun's magnetic field is very dynamic in nature. Sometimes it suddenly snaps and releases intense bursts of energy in a powerful, short flash. 
    • The energy is released in the form of light/radiation and high energy charged particles. 
  • Solar flares tend to originate from regions of the solar surface that contain sunspots.
    • Sunspots are darker and cooler portions of the solar surface, where magnetic fields are particularly strong. 
  • The number of sunspots can indicate the likelihood of a solar flare eruption.
Solar Flares

Impacts of Solar Flares on Earth

  • Strong flares can trigger coronal mass ejections (a large release of plasma and magnetic field from the sun).
    • This can disrupt Earth's magnetosphere and result in geomagnetic storms. 
    • Such geomagnetic storms can lead to auroras closer to the equator than is possible during calm conditions.
  • Emission of fast-moving charged particles (carrying a lot of energy) can endanger astronauts and Earth-orbiting spacecraft. 
  • Impacts satellites and thus disrupts GPS navigation, Satellite Television, Air Traffic Communication systems. 
  • Minor to extensive radio blackouts (mainly impacts high frequency radio communications) on the side of Earth facing the sun. 
  • Damage Power grids and cause electrical blackout.
Impacts of Solar Flares on Earth