Astronomy & Space Technology

Chandrayaan 5 Mission

Context: Indian Government has approved the Chandrayaan 5 mission which will be jointly conducted by the Indian Space Research Organisation (ISRO) and the Japan Aerospace Exploration Agency (JAXA).

Relevance of the Topic: Prelims: Key facts about Chandrayaan Mission series.

Chandrayaan 5 Mission

Chandrayaan-5 or LUPEX (Lunar Polar Exploration) aims at deeper exploration of the Moon’s surface to study water and water-ice both on the lunar surface and the subsurface.
The LUPEX mission will be launched from the Tanegashima Space Center, Japan by a Japanese rocket (H3 Launch Vehicle).
- H3 is a three-stage launch vehicle powered by solid-fuels and cryogenic fuels (Liquid hydrogen and liquid oxygen). It is 63 meters tall and weighs 574 tons.
The mission is expected at a little over 100 days after the lunar landing, or for a maximum of one year.
Tentative launch: 2027-28

Joint project between ISRO and JAXA:

ISRO will build the lunar lander, while Japan will build the rover.

The LUPEX craft would weigh 6,500 kg approximately, and this includes a 350 kg rover.
The rover will drive on its own to search for areas where water is likely to be present and sample the soil by digging into the ground with a drill. The collected samples will be analysed in detail with observation equipment mounted on the rover.

Scientific payloads that LUPEX will be carrying:

LUPEX will be carrying a total of 10 scientific payloads. These include five payloads from JAXA, three payloads from ISRO, and one payload each from NASA and the European Space Agency.
The payloads are: Resource Investigating Water Analyzer (REIWA), Lunar Thermogravimetric Analyzer (LTGA), Triple-reflection Reflectron (TRITON), Aquatic Detector using Optical Resonance (ADORE), International Symposium of Antennas and Propagation (ISAP), Advanced Lunar Imaging Spectrometer (ALIS), Neutron Spectrometer, Ground Penetrating Radar, Exospheric Mass Spectrometer for LUPEX (EMS-L), Mid-Infrared Imaging Spectrometer (MIR).

Lunar Missions by ISRO:

Chandrayaan-1:

India's first moon mission launched in 2008.
Launch vehicle: Polar Satellite Launch Vehicle (PSLV)
The spacecraft orbited around the Moon at a height of 100 km. It mapped the Moon in infrared, visible, and X-ray light from lunar orbit, and used reflected radiation to prospect for various elements, minerals, and ice.
It released an impactor (Moon Impact Probe- MIP) that studied the thin lunar atmosphere before crashing on the Moon’s surface.
It gave definitive proof of the presence of water ice in the Moon’s atmosphere and surface.

Chandrayaan-2:

Second moon mission launched in 2019.
Launch vehicle: LVM-3
The spacecraft consisted of an orbiter, a lander, and a rover.
The orbiter circled the Moon in a polar orbit at a height of 100 km, and has a planned mission lifetime of seven and a half years.
Vikram lander planned to demonstrate soft landing on the moon, however, it crashed due to a software error. Despite it, 90-95% of the mission objectives have been accomplished.
It has enriched understanding of the Moon's evolution and mapped minerals and water molecules in the Polar Regions.

Chandrayaan-3:

Third moon mission launched in 2023.
Launch vehicle: LVM3
The spacecraft consisted of Vikram lander and Pragyan rover. The Vikram lander touched down on the Moon on August 23, 2023.
It made one of the closest approaches to the moon's South Pole. The landing site is located about 600 kilometers from the South Pole of the Moon, on the near side of the Moon.
The rover operated for one lunar day (approximately 14 Earth days). It aimed to collect lunar samples, do in-situ experiments and send data to Vikram lander, to transmit it back to Earth.
India became the fourth country to land spacecraft on the Moon after the US, Russia, and China.
The Virtual Launch Control Centre at the Vikram Sarabhai Space Centre played a vital role in continuous real-time monitoring of the launch activities from SHAR.
The International Astronomical Union (IAU) has approved the name “Statio Shiv Shakti” for the landing site of Chandrayaan-3’s Vikram lander.

4. Chandrayaan-4:

Planned lunar sample return mission expected to launch around 2027.
Aim: To collect samples from the moon's surface and bring them back to the Earth.
Landing site: Planned near Statio Shiv Shakti (landing site of Chandrayaan-3), near south pole region.
Design: The spacecraft would comprise five modules onboard two separate LVM-3, and will be docked in the Earth orbit. In the final lunar orbit, the modules will undock. The samples will be collected and brought back to Earth.

Why is there a lot of interest in water on the moon ?

Water can be electrolysed (split) to produce rocket fuel (oxygen and hydrogen). If there is enough water, it will be an important resource for future crewed space activities because it will eliminate the need to transport large quantities of fuel from the earth.

LUPEX will land in an area where past remote sensing observations indicate the high possibility of the existence of water (ice). LUPEX rover will directly measure the water content by in-situ observation.

The Chandrayaan-5 / LUPEX mission will be one of the major short-term milestones in India’s lunar exploration odyssey, which envisions Indian Gaganyatris (astronauts) landing on the Moon by year 2040.

Soviet spacecraft Kosmos 482 crashes to Earth after 53 years

Context: A piece of a Soviet spacecraft, Kosmos 482, launched more than 50 years ago crashed back to Earth, splashing into the Indian Ocean off Jakarta's western coast, Indonesia.

Relevance of the Topic: Prelims: Key facts about Soviet spacecraft Kosmos 482.

Kosmos 482 Mission:

Kosmos 482 Mission is one among the series of probes launched to explore Venus by the erstwhile Soviet Union. Under the Venera Program, the Soviet Union sent 28 spacecraft to Venus between 1961 and 1984.
The probe was launched in 1972 with the purpose of landing on Venus. It consisted of various instruments to measure the temperature, pressure, wind speed, visibility, atmospheric gases and rock composition, and radio the results back to Earth.

What went wrong with Kosmos 482?

Soon after the launch, a malfunction took place in the rocket. The upper rocket stage/engine (that was meant to propel the Kosmos 482 out of the Earth orbit) shut off too early due to a timer malfunction.
As a result, the spacecraft was left stranded in an orbit around the Earth. The lander module, which was supposed to land on Venus, broke apart from the main spacecraft. It kept orbiting the Earth for over 50 years. The main spacecraft, which was large and heavy, burned up in the (Earth’s) atmosphere.
Within the period of over 50 years, the spacecraft's orbit decayed slowly as the atmospheric drag slowly pulled it towards the Earth, leading to its re-entry into the Earth.

Concerns:

Growing space junk: Kosmos 482's reentry into the Earth serves as a reminder of the growing issue of space junk. While most space objects plunge into Earth's atmosphere and burn up; some particularly heavy or dense objects such as Kosmos 482, survive the hot reentry.
Environmental damage: Researchers also warn that satellite and space reentry can discharge harmful pollutants in the atmosphere of Earth and destroy the ozone layer and the environment at large, leading to climate change.

Also Read: What is Satellite Pollution?

With the volume of space traffic increasing, space debris management and minimising its environmental impacts will be an increasingly important issue.

Asteroid YR4 may hit Moon in 2032

Context: National Aeronautics and Space Administration (NASA) has announced that there is a 3.8% chance that Asteroid YR4 could collide with the moon in December 2032.

Earlier, it was thought the asteroid might hit Earth, but the latest trajectory analysis concludes a very little chance of that happening. The asteroid is below the threshold size (140 metres), so it would not be a threat to Earth.

Relevance of the Topic:Prelims: Key facts about Asteroid 2024 YR4; Double Asteroid Redirection Test spacecraft (DART).

About Asteroid 2024 YR4

The 2024 YR4 was first discovered in December 2024 by a telescope in Chile.
It is a near-Earth asteroid measuring 40 to 100 metres across.
It came closest to Earth in December 2024— passing within roughly 800,000 kilometres of Earth, about twice the distance of the moon.
Scientists are using some of the most powerful telescopes to determine 2024 YR4’s path and size before it gets out of sight (becomes too faint to observe).
One AU (Astronomical Unit) is approximately equal to 93 million miles - the distance between the Sun and the Earth.
The closest asteroids which travel within 1.3 AU of the sun are called near-Earth objects (NEO).

If an NEO's orbit also intersects Earth's orbit, and the object is larger than about 140 metres in diameter, then it is classified as a potentially hazardous object (PHO).

The Challenge

Determination of the size of Asteroid:
- To determine the size of an asteroid, astronomers examine the brightness of the object — brighter objects are bigger.
- However, the brightness depends on how reflective the asteroid’s surface is (asteroids do not emit a light of their own, they only reflect sunlight).
- As a result, it is a challenge to distinguish between a large, dark-colored asteroid and a small, highly reflective one.
1% chance of crashing into Earth:
- The 2024 YR4 is expected to release 8 to 10 megatons of energy in case of a crash. Its impact could be 100 times more powerful than an atomic bomb.

What are Asteroids?

Asteroids are rocky remnants from the early formation of our solar system (about 4.6 billion years ago).
They are rocky, metallic, or icy bodies with no atmosphere.
Roughly one million asteroids are known. Majority of them are located between the orbits of Mars and Jupiter, in a region known as the main asteroid belt.
- The asteroid belt is a nearly flat ring that contains millions of asteroids, about 1000 kms or less in diameter.
- The largest asteroid in our solar system is Ceres (diameter ~940 kms), which is about one-quarter the size of Earth’s moon.
They are generally classified to be of three types: C-type, M-type, and S-type, i.e., carbonaceous, metallic, and siliceous compositions, respectively.
The first close-up observation of an asteroid was made by the NASA’s Galileo spacecraft (1991).

Asteroids as threats from Space

Thousands of Asteroids enter the Earth’s atmosphere every day. Most are very small and burn up in the atmosphere due to friction.
In some cases, unburnt fragments reach the Earth’s surface, although they are not large enough to cause much damage.
- In 2013, a 20-metre-wide asteroid entered the atmosphere and exploded about 30 km above a Russian town.
- Most of the energy released was absorbed by the atmosphere, however, shock waves travelled to the ground, damaged buildings, trees and injured people.
Space agencies are working on planetary defence mechanisms that can prevent celestial bodies from colliding with Earth with potentially catastrophic consequences.

Planetary Defence Mechanisms:

1. Double Asteroid Redirection Test spacecraft (DART):

DART was the first planetary defence mission of NASA, launched in 2021, to test a method for defending Earth from potentially hazardous asteroids.
Target:
- It targeted the binary asteroid system which consists of a larger asteroid called Didymos and a smaller asteroid called Dimorphos.
- Dimorphos did not pose a threat to Earth, and was circling the Sun some 11 million kilometres away from the planet.
Objective: To intentionally crash the DART spacecraft into Dimorphos to slightly alter its orbit around Didymos.
Impact: In 2022, DART spacecraft crashed into Dimorphos, and successfully changed both its shape and its trajectory.
Significance: The data gathered from DART will help scientists develop more effective strategies for deflecting asteroids that pose a threat to Earth in the future.

2. OSIRIS-APophis EXplorer (OSIRIS-APEX):

NASA has redirected its Space-craft OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security – Regolith Explorer) that previously studied the asteroid Bennu, to track Asteroid Apophis.
OSIRIS-APEX is a mission to study the physical changes to asteroid Apophis that will result from its rare close encounter with Earth in April 2029.
Our planet’s gravitational pull is expected to alter the asteroid’s orbit, change how fast it spins on its axis, and possibly cause quakes or landslides that will alter its surface. OSIRIS-APEX will allow scientists on Earth to observe these changes.
Additionally, the OSIRIS-APEX spacecraft will dip toward the surface of Apophis and fire its engines to kick up loose rocks and dust. This manoeuvre will give scientists a peek at the composition of material just below the asteroid’s surface.

Scientists find second Natural Source of Gold

Context: Researchers have reported that the universe may have another way to produce the element gold, apart from collision of neutron stars. They have reported the first direct observational evidence of a process called r-process nucleosynthesis in a powerful flare emitted by a magnetar in 2004.

Relevance of the Topic: Prelims: Key facts about Neutron stars; Magnetars; r-process nucleosynthesis.

Known Source of Gold- Neutron Star Collisions:

Neutron Stars: Incredibly dense remnants of supermassive stars (with masses around 10²⁵ times the mass of the Sun) that have exploded as supernovae.
Gold is predominantly produced in the violent collisions and mergers of ultra-dense neutron stars. Such events are detected using space telescopes and gravitational wave detectors (E.g., LIGO).

The New Discovery- Magnetar Flares produce Gold

Magnetars: Types of neutron stars with much more powerful magnetic fields than normal neutron stars. Most powerful known magnetic objects in the universe with magnetic fields in the range of 10¹⁵ gauss.
Magnetar Flares: Magnetar occasionally release large bursts of energy in flares (much powerful than solar flares).
Observation:
- A powerful flare emitted by a magnetar in 2004 was recorded by NASA's Compton Gamma Ray Observatory.
- Almost a day after the flare, a delayed burst of high-energy gamma rays was released.
- The delayed emission was inconsistent with standard flare afterglows and contained evidence of radioactive decay from r-process nucleosynthesis.
r-process nucleosynthesis: The rapid neutron capture process is the major nucleosynthesis process responsible for the synthesis of heavy nuclei, including gold.
The study concludes that some magnetar flares can eject neutron-rich matter into space, where it goes through r-process nucleosynthesis to create heavy elements like gold.

Significance

The early universe only had hydrogen, helium, and trace amounts of lithium. All other elements were created later in stars, cosmic explosions, and laboratory experiments. Mapping the sources tells us how galaxies, stars, and planets took shape over time.
Understanding the sources can also reveal how often an element was produced, and how the presence of an element influenced the source’s own evolution.

Also Read: What are Fast Radio Bursts?

ISRO’s breakthrough in Semi-Cryogenic Engine development for LVM3

Context: Indian Space Research Organisation has successfully conducted the second short duration hot test of the Lox Kerosene 2,000 kiloNewton (kN) semi-cryogenic engine (SE2000). Earlier, the first major hot test of the engine was conducted in March 2025.

During the test, the engine was successfully ignited and operated up to 60% of its rated power level, demonstrating stable and controlled performance.

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

ISRO’s Semi-cryogenic Engine

The Liquid Propulsion Systems Centre of ISRO is developing the Semi cryogenic propulsion Engine and Stage (SC120).
The stage (SC120) is powered by the 2000 kN semi-cryogenic engine (SE2000). It uses a Liquid Oxygen and Kerosene-based propulsion system that offers an enhanced thrust of 2,000 kiloNewton.
It will replace the present core liquid stage (L110) (which uses Vikas engine) in Launch Vehicle Mark-3 (LVM3).

Evaluation Tests on Semi-cryogenic Engine:

Before the full integration of the SE2000 engine, ISRO conducted a series of performance evaluation tests on intermediate configurations.
- Pre-Burner Ignition Test Article (PITA): Tests the ignition process of the engine’s pre-burner. The successful test lasted 2.5 seconds, demonstrating the smooth ignition and operation of the engine.
- Power Head Test Article (PHTA): Validates the integrated performance of an engine's critical subsystems, including the gas generator, turbo pumps, pre-burner and control components. It involves performing a hot-firing of the engine for an extremely brief duration of not more than 4.5 seconds.
All critical parameters performed as expected, marking a major breakthrough in the semi-cryogenic engine development program.

Benefits of Semi-cryogenic Propulsion System:

Non-toxic and non hazardous propellants (Liquid Oxygen and Kerosene) are employed in Semi cryogenic propulsion. This will deliver higher performance compared to the existing L110 stage.
Induction of the Semi cryogenic propulsion system along with an uprated cryogenic stage in the LVM3 vehicle enhances its payload capability from 4 tonne to 5 tonne in GTO (Geosynchronous Transfer Orbit).

Advantages of Semi-cryogenic Engine over Cryogenic Engine:

Cryogenic engines use liquid oxygen and liquid hydrogen. Handling liquid hydrogen is challenging, as it needs to be stored at minus 253 degrees Celsius, and 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), less toxic (with respect to fuel storage) and is cost-effective.

Significance: The success of the test brings ISRO a step closer towards enhancing the payload capacity of India's LVM3 rocket and strengthening the country's capabilities in space launch vehicles.

Does the planet K2-18b show signs of life?

Context: Recently, an international research paper reported that the distant exoplanet K2-18b may be habitable. Potential biomarkers were identified based on the observations from James Webb Space Telescope, backed by computer-based spectral analysis.

Relevance of the Topic:Prelims: Key facts about K2-18b.

What is K2-18b?

K2-18b is an exoplanet — a planet outside the solar system. It is located 124 light years away from the earth in the constellation Leo, orbiting the star K2-18.
It is over 5 times wider and roughly 9 times more massive than the Earth.
The amount of stellar radiation it receives from its star is comparable to what the Earth receives from the Sun. It likely possesses a hydrogen-rich atmosphere.
It was discovered by the Kepler telescope in 2015.

Earlier estimations of planetary conditions in K2-18b:

In 2019, the Hubble Space Telescope found that its atmosphere contains signs of water vapour. Later, the James Webb Space Telescope detected signs of carbon dioxide and methane.
Studies suggest, K2-18b might be a Hycean world: covered with an ocean overlaid by a hydrogen-rich atmosphere.

Researchers suggest its surface conditions may be close to the runaway greenhouse threshold — when the concentration of greenhouse gases in the atmosphere prevents any heat from escaping the surface.
Computer models suggest it may also have a stratosphere and some carbon oxides and cyanide in the middle atmosphere.

Recent findings that suggest K2-18b might be habitable:

The latest research reported the presence of at least one of two molecules that are associated with life: dimethyl sulphide (DMS) and dimethyl disulphide (DMDS) in K2-18b’s atmosphere.
DMS could be a biomarker (a sign of life) on exoplanets. On Earth, these gases are produced by marine phytoplankton and bacteria.
- Phytoplankton produce a molecule called dimethylsulphoniopropionate (DMSP). When they die, enzymatic breakdown of DMSP molecules releases DMS.
- DMS is also emitted when bacteria break up plant matter. In 2015, researchers reported that 76% of soil bacteria contain a gene that allows them to produce DMS.
- Volcanic eruptions also release trace amounts of DMS.

However, attempts to look for conditions suitable for life and the presence of specific molecules from a distance can only be suggestive of habitable conditions, not confirmatory. The only way to find extraterrestrial life is to directly detect it.

NASA has launched its Clipper Mission in 2024 to study Jupiter’s moon Europa, which among other objectives aims to track signs of life in its vapour plumes.

Blue Origin's New Shepard Mission

Context: Recently, Jeff Bezos’s Blue Origin launched its 31st New Shepard Mission featuring an all-women crew.

Relevance of the Topic: Prelims: Key facts about New Shepherd mission; Karman line.

31st New Shepard Mission

It was a sub-orbital spaceflight conducted by Blue Origin, a private American aerospace and space exploration company founded by Jeff Bezos. It featured the first all-female crew comprising a six-woman team.
The flight lasted approximately 10 minutes and 21 seconds, reaching 106 km above Earth, crossing the Karman line, internationally recognised boundary of space.
This mission was part of Blue Origin's ongoing efforts to expand commercial space tourism and demonstrate the reusability of their New Shepard vehicle.

New Shepard Mission

New Shepard is a sub-orbital launch vehicle developed for space tourism. The vehicle is named after Alan Shepard, the first American astronaut in space.
The vehicle is capable of vertical take-off and landings and can carry humans and customer payloads to the edge of space.
The rocket consists of a booster rocket and a crew capsule. The capsule can be configured to house up to six passengers, cargo, or a combination of both.
The booster rocket is powered by one BE-3PM engine, which sends the capsule to an apogee (Sub-Orbital) of 100.5 kilometres and flies above the Karman line.
The launch vehicle is designed to be fully reusable, with the capsule returning to Earth via three parachutes and a solid rocket motor. The booster lands vertically on the same launchpad it took off from.

Karman Line

The Karman line is an imaginary line 62 miles (100 kilometers) above mean sea level that is generally accepted as the boundary separating Earth's atmosphere and outer space.
It is conventionally used as the start of outer space in space treaties and for aerospace records keeping. An aircraft which crosses the Karman line is designated as a spaceflight. Anyone who crosses this line qualifies as an astronaut.
- Below the Karman line, aerodynamic principles dominate flight. Above it, the laws of orbital mechanics become more important.
- At the Karman line, the atmosphere becomes incredibly thin. Traditional aircraft that rely on wings to generate lift by pushing against air cannot function effectively at such high altitudes.
- Over the Karman line, the spacecraft need their own propulsion systems to maintain trajectory and overcome the remaining atmospheric drag, though minimal.

How is safety ensured in Gaganyaan Spaceflight Mission?

Context: The recent safe return of NASA astronauts Sunita Williams and Barry Wilmore from the International Space Station (ISS) has brought attention to the critical importance of robust safety protocols in human spaceflight. The mission lasted nine months and highlighted NASA's behind-the-scenes efforts to ensure astronaut safety—physically and mentally.

Relevance of the Topic: Prelims: Key facts related to Gaganyaan Human Spaceflight safety.

As India advances towards its maiden human space mission, Gaganyaan, the Indian Space Research Organisation (ISRO) is meticulously putting similar protocols in place, drawing from both historical precedents and modern aerospace research.

Safety Protocols in Gaganyaan (Human Spaceflight Mission)

1. Crew Escape System:

Human-rated LVM3 (launch Vehicle Mark-3) is equipped with a Crew Escape System that acts like an emergency door — allowing the astronauts to rapidly detach and escape safely from the rocket, if anything goes wrong after the rocket has taken off.
It uses a tower-like structure on the top of the rocket containing solid fuel engines designed to ignite quickly and produce a tremendous amount of thrust in a short period of time, propelling the space capsule upwards and away from the rocket.
The Crew Escape System adjusts its response depending on how high the rocket is. It uses LEM for low altitudes and HEM for high altitudes, ensuring the astronauts can escape safely at any stage during launch.
- Low-altitude Escape Motor (LEM): Used in the initial seconds after takeoff. Produces enough thrust to quickly pull the crew module away from the rocket when it is still near the ground.
- High-altitude Escape Motor (HEM): Activates when the rocket is much higher in the sky. Provides enough pulling force to separate the crew module from the rocket safely, even at high speed and altitude.

2. Pad Abort System: Emergency Escape Right After Ignition:

Pad Abort refers to a life-threatening emergency that happens just moments after the rocket engines ignite, while the rocket is still on or very close to the launchpad.
In this scenario, both motors LEM and HEM of ISRO's Crew Escape System are activated. Together, they provide maximum thrust to quickly pull the entire crew module and escape system away from the rocket as fast as possible. After escaping, the crew module will splash down safely in the sea at a pre-decided location.

3. Safety in Orbit:

ISRO’s Gaganyaan crew capsule consists of a pair of interconnected modules:
- Crew module: serves as the living quarters for the crew and passengers)
- Service module: carries the fuel, engines, control systems, etc.
By the time the spacecraft reaches near its target orbit, the Crew Escape System is no longer needed and is discarded in space.
If an emergency arises before reaching full orbit, the service module’s propulsion system can change the flight path and bring the crew module down safely on a sub-orbital trajectory (meaning it will come back to Earth without completing an orbit).
If something goes wrong after the spacecraft is already in orbit, then both the service module’s engines, and the crew module’s small thrusters will work together to slow down the spacecraft and guide it back into Earth’s atmosphere for a safe return.

4. Returning to the Earth:

Once reentry has begun, atmospheric friction will heat the capsule’s outer heat shield to up to 1800º C. The crew in the crew module will be protected by the shield. Once the capsule has descended to a particular altitude, the crew will slow its descent using retrograde thrusters and deploy parachutes.

5. Final Descent Using Parachutes:

Gaganyaan crew capsule will decelerate throughout re-entry using a multi-stage parachute system (10-parachute system) to reduce speed in phases:
- Apex cover separation parachutes deploy at 15.3 km altitude from the ground and at 276 m/s speed.
- After that, drogue parachutes are deployed to stabilise and decelerate the capsule to 70 m/s up to a height of 3 km.
- Then the three primary canopies will be deployed, reducing the drop speed to 10-12 m/s.
Splashdown: Just before or after splashdown in the sea, the parachutes are disconnected using a pyrotechnic mechanism.

Also Read: Gaganyaan Mission

ESA’s Biomass Mission

Context: The European Space Agency (ESA) is set to launch its ambitious Biomass Mission on April 29 from the ESA’s Korou spaceport in French Guiana.

Relevance of the Topic: Prelims: Key facts about ESA’s Biomass Mission; Carbon Cycle.

ESA’s Biomass Mission

The satellite will be placed in the sun-synchronous orbit at an altitude of ~666 km. (it will always appear in the same position relative to the Sun).
Objective: Map the world’s forests to provide the very first comprehensive measurements of forest biomass at a global scale. Create 3D images of forests — from the top of the forest canopy to the roots of its trees.
Beyond forest monitoring, the mission will also observe the movement of ice sheets in Antarctica, and generate digital models of terrains covered by dense vegetation.

Working

The mission will use a SAR (synthetic aperture radar) to map the Earth’s surface. The satellite is fitted with a massive 12-m antenna, and will be the first satellite in space to use a long-wave P-band SAR.
This will help it penetrate dense forest canopies to assess how much carbon is stored on the floor and in the branches of the trees, and to assess how these levels are changing over time. Longer wavelengths of electromagnetic radiation penetrate matter more than shorter wavelengths.

Significance: Enhance understanding about the role of forest in the carbon cycle. Allow scientists to more accurately measure how the distribution of carbon in the planet is changing, as humans continue to cut down trees, and increase CO2 levels in the atmosphere.

Carbon Cycle:

Carbon cycle is the process that moves carbon between plants, animals, and microbes; minerals in the earth; and the atmosphere. All lifeforms on Earth, including the smallest microbes, are carbon-based. Earth does not gain or lose carbon. The element only moves between the atmosphere, living organisms, Earth’s crust and soil, and the oceans.
Forests are an essential part of the carbon cycle. Forests store massive amounts of carbon (absorb around ~16 billion metric tonnes of carbon dioxide (CO2) per year), and hold 861 gigatonnes of carbon in their soils and vegetation.
Data on forest biomass (mass of organic matter in forests) is severely lacking on a global scale. This fundamentally limits our understanding of the state of the forests, and their impact on the carbon cycle (and climate). The Biomass mission aims to bridge this knowledge gap.

Note: According to a report by the World Resources Institute, in 2023, Earth lost 3.7 million hectares of tropical forests, equivalent to losing around ten football fields worth of forest land every minute. This forest loss produced roughly 6% of estimated global CO2 emissions in 2023.

Iron Opacity in the Sun and its Implications on Stellar Models

Context: Scientists have found a mismatch between the predicted opacity of iron inside the Sun and what experiments are now showing. This mismatch could affect solar models, and in our understanding of all stars, galaxies and even the universe's evolution.

Relevance of the Topic: Prelims: Facts related to iron opacity in the Sun.

What is Opacity?

Opacity is the measure of how much light or radiation a material can absorb.
Higher opacity = More absorption of light = Less light transmission.
In the context of the Sun, opacity determines how energy generated in the core moves toward the surface.

Why does Iron Opacity matter in the Sun?

The Sun is used as a model to study and understand other stars and stellar evolution. Energy transport within the Sun depends on how much radiation is absorbed by elements like iron.
If opacity is underestimated, temperature profiles, element abundances, and other stellar properties in models become inaccurate.

Observations vs Models

Until the 2010s, studies showed: 30–50% less carbon, oxygen, nitrogen in the Sun than predicted. Solar models still predicted brightness and neutrino output correctly.
A 2015 study tested iron under Sun-like conditions and found its opacity was 30-400% higher than expected.
Full clarity will come with absolute opacity measurements – that is still in progress.

Implications for Astrophysics

Discrepancy in opacity affects understanding of Stellar internal temperatures; Elemental composition and transport; Nuclear fusion rates and energy generation
Larger implications: Inaccurate prediction of planetary habitability; Miscalculation of galactic evolution; Errors in modeling cosmic structures and interstellar chemistry.

Fram2 Mission

Context: Fram2 mission, a private space mission led by a cryptocurrency billionaire, has returned after completing a journey of three and a half days.

Relevance of the Topic: Prelims: Key facts about Mission Fram2.

Overview of Fram2 Mission

Name: Fram2 (named after the 20th-century Norwegian South Pole exploration ship "Fram")
Type: Private mission launched by SpaceX
Launch Vehicle: Falcon 9 rocket
Spacecraft: SpaceX Dragon capsule.
Launch Site: NASA’s Kennedy Space Center, Cape Canaveral, Florida.
Launch Date: March 31, 2025
Funded by: Chun Wang, a cryptocurrency entrepreneur from Malta
Duration of mission: 3.5 days
Crew Members: Chun Wang (Malta) – Cryptocurrency entrepreneur and his three guests.

Key facts about Fram2 Mission:

First human mission to fly in polar orbit (over both the North and South Poles)
First SpaceX human crew to return via Pacific Ocean splashdown.

Scientific Objectives:

The crew conducted 22 microgravity experiments before safely returning to Earth. They include-

First X-ray of the human body in orbit.
Studying radiation exposure in polar orbits.
Testing advanced space communication via the Starlink network.
Conducting biomedical research on the human body’s adaptation to polar orbital conditions.
Growing mushrooms in space—a first in space agriculture.

Polar Orbit Significance

A polar orbit is where a spacecraft orbits Earth by passing over the North and South Poles. Instead of moving around the equator like many satellites, it travels from top to bottom (north to south) and then back up.
Common for satellites, but unprecedented for humans.
Requires higher energy and modifications due to the flight path over less populated regions.
Software modifications made to ensure emergency safety during southward launch.

ChaSTE: First in-situ measurement of Surface Temperature

Context: Chandrayaan-3's ChaSTE provided crucial temperature data from the Moon's high-latitude regions, enhancing the understanding of potential water-ice deposits.

Relevance of the Topic: Prelims: Key facts about Chandrayaan Mission 3; Chandra’s Surface Thermophysical Experiment (ChaSTE).

Chandra’s Surface Thermophysical Experiment (ChaSTE)

ChaSTE is an instrument aboard the Vikram lander to measure temperatures in situ near the moon’s south pole.
ChaSTE became the first mission to successfully penetrate the soil of a celestial body to deploy a thermal probe for in-situ measurement of the surface temperature.
- The ChaSTE probe features 10 temperature sensors spaced about 1 cm apart along its length.
- The probe was pushed into the lunar soil using a rotation-based deployment mechanism.
- ChaSTE tunnelled into the soil to a final depth of 10 cm, then collected the measurements throughout the Chandrayaan-3 mission lifespan (1 lunar day).

Observations:

In-situ temperature measurement: The peak surface temperature at Shiv Shakti landing site was measured to be 355 K (82°C) — 25 K higher than the expected 330 K, predicted by earlier observations.
The observations indicate that the lunar surface temperatures show a significant spatial variability at high latitudes, unlike at the equatorial regions.

Scientists used the data from ChaSTE to report that water ice is more prevalent on the moon than expected. Water-ice prospecting is a crucial step in unlocking the Moon’s potential for supporting human habitat and furthering exploration.

Also Read: Chandrayaan-3 Hop Experiment