SPA basin is one of the Moon’s largest and oldest impact features in the solar system. The Chandrayaan-3 landing site is located 350kms from the basin.

Researchers said the findings, published in Nature Communications Earth and Environment on Wednesday, could aid in the study of the early evolution of the Moon.

Analysing the concentrations of volatiles (chemical elements and compounds) measured by the Alpha Particle X-ray Spectrometer (APXS), an instrument on-board the Pragyan rover at Shiv Shakti statio near the South Polar Region, the 12-member team found high levels of sulphur at the Chandrayaan-3 highland landing site in the range of 900-1400 ppm, which was 300-500 ppm (parts per million) higher than in soil samples from lunar highlands from in Apollo 16 and Luna 20 missions.

However, the levels of sodium and potassium from the Chandrayaan-3 landing site was found to be much lower at 700-2800ppm and 300-400 ppm respectively as compared to the earlier missions. The APXS experiment was designed and developed by PRL, a unit of the department of space.

Researchers said the differences in the concentrations of these volatile elements as compared to those found in Apollo 16 and Luna 20 missions make it important to investigate the probable source that led to their enrichment or depletion at the Chandrayaan-3 landing site.

Explaining how the team arrived at the present conclusion, Rishitosh K Sinha, lead author of the study said that on the Moon, around 400-1000 ppm of sulphur can come from Type I carbonaceous chondrite (CC) meteorites crashing on the lunar surface.

“However, this is still less by 200-400 ppm than what APXS measured at the landing site. Moreover, the surface temperatures at the landing site, which is located at 70 degrees south in the Southern Polar region, is much higher for sulphur to condense in the plume as compared to if the site was closer (85-90 degrees) to the South Pole,” said Sinha. Closer to the South Pole, where surface temperatures are lower, sulphur can condense into solid form.

Therefore, said Sinha, there had to be another source of sulphur that increased its concentration at the landing site. “The other possible source for excess sulphur therefore would be the primitive lunar mantle material that would have thrown up during the SPA basin formation.”

He further explained that the low levels of sodium and potassium at the Chandrayaan-3 landing site as opposed to the Apollo 16 and Luna 20 missions suggests that potassium, rare earth elements, and phosphorus (called KREEP) might not have existed at the place and time of SPA basin formation. “This new finding therefore makes the Chandrayaan-3 landing site a promising site to access primitive mantle samples, which is otherwise lacking in the existing lunar collections,” said Sinha.

Sinha said during the end of the lunar magma ocean (LMO) crystallisation stages, when the Moon’s initial molten state solidified, the residual molten layer became enriched in a mineral called Troilite (FeS). “We have proposed that the SPA basin impact event excavated this FeS from the sulphur-enriched primitive lunar mantle, while the KREEP layer was still in the process of formation. The subsequent impacts on the SPA basin ejecta stirred things up, mixing sulfur-rich materials from the SPA basin with the nearby material at the landing site,” he said.

On August 23, 2023, the Chandrayaan-3 mission made the first successful landing in the South Polar region of the Moon following which APXS directly measured the elemental composition of the Moon’s surface at Shiv Shakti statio, an unexplored location, in the southern high-latitude highlands of the nearside of the Moon.

Last year, a study published in Nature by the same group had found evidence of high magnesium in the soil at the same landing site that could have originated from the deeper layers of the Moon. It provided clues for the presence of lower crust and/or upper mantle materials at the landing site. “High magnesium also comes from the mantle. With evidence of high concentrations of sulphur now, the present study becomes robust since it complements the previous study.”

Anil Bhardwaj, Director PRL, also a co-author in this study, said that finding primitive mantle material is important because Apollo and Luna missions only comprised collections of lunar samples. “We really don’t have samples from the lunar mantle. These samples are crucial to understand how the Moon was formed, what connection does it have with the Earth, presence and proportion of volatile elements in the lunar interior and how it evolved over time,” said Bhardwaj.

Commenting on the significance of the study, Rajesh VJ, professor, department of earth and space sciences at the Indian Institute of Space Science and Technology, Thiruvananthapuram, who was not involved with the study, said, the primitive mantle material from any planetary bodies is significant, as it provides vital information about the chemical composition of the early materials (rocks/minerals) present towards the deeper part (especially the mantle), before it underwent any sort of petrological modifications.

Hence, these materials are used by geoscientists to understand the origin and early evolution of a planetary body. “The discovery of sulphur-rich primitive mantle materials provides a rare opportunity for planetary scientists to conduct detailed investigations of the early evolution of the Moon. It provides the scientific community with more vital information about the composition of the lunar interior and its volatile contents,” he said.

Earth’s forests are pivotal to keeping our planet habitable. Freely referred to as the “lungs of the Earth,” they blanket about one-third of the globe and have a significant function to play in modifying the weather. Forests also take in enormous quantities of carbon dioxide (CO₂) from the air — approximately 7.6 billion metric tons each year, NASA says — and emit oxygen, which makes life on Earth viable.

ESA launched Biomass satellite to study forest carbon estimation

According to ESA, to meet this challenge Biomass satellite is deployed into orbit on 29 April 2025 Tuesday aboard a Vega-C rocket from Europe’s Spaceport in Kourou, French Guiana, at 11:15 CEST (06:15 local time).

The mission represents a giant leap in monitoring forests and climate studies. Biomass is the first satellite to be equipped with a P-band synthetic aperture radar — a technology that can penetrate deep into forest canopies and show detailed, three-dimensional structures of the trees beneath. Imagine it as an Earth-sized MRI machine. By taking the density and structure of tree trunks, branches, and stems, Biomass will enable scientists to estimate the amount of carbon in forests as well as how much is emitted.

Why forest monitoring is becoming increasingly urgent

Though essential, forests are being increasingly threatened by human action. Deforestation, land degradation, and even increasing fires are diminishing their capacity to sequester CO₂. Hence, forests in most places — particularly tropical forests — are starting to emit more carbon than they lock away, fueling global warming. Tracking how forests react to increasing levels of greenhouse gases and environmental stressors is tricky. Thick forest cover and dense vegetation hinder the measurement of forest health on the ground or even using conventional satellite imagery.

Biomass satellite measuring forest carbon to track climate change

“With Biomass, we are set to harvest critical new information about the amount of carbon held in forests around the globe, which will help to close important knowledge gaps regarding the carbon cycle and, in the end, Earth’s climate system,” explained Simonetta Cheli, ESA’s Director of Earth Observation Programmes. This data is critical. Standing forests have a tendency to retain more carbon than they release. But because of extensive deforestation and forest loss, most forests — especially those in the Amazon and Southeast Asia — have reversed from being carbon sinks to becoming carbon sources.
“This new mission will enhance our capability to measure forest carbon stocks and fluxes, which is at the heart of understanding and estimating the effects of climate change,” said Michael Fehringer, ESA’s Biomass Project Manager.

Biomass satellite to track forest carbon

The satellite was produced with the involvement of 50 partner companies, including project lead Airbus UK. In the days ahead, mission controllers will check that the satellite’s systems are working as they should. Once operational, Biomass will start generating 3D maps of forest biomass and carbon distribution, enabling scientists to better understand the changing role of forests in the global carbon cycle. As climate change speeds up and forest health declines, accurate, real-time data is more important than ever. Biomass will enable scientists, policymakers, and conservationists to know where and how to intervene — whether it’s safeguarding carbon-dense forests or quantifying the actual effect of deforestation. The mission won’t halt climate change by itself, but it might be an essential component in the worldwide effort to slow its impact.
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Puttur city municipality in Dakshina Kannada district use Bio CNG generated from wet waste to operate its six vehicles since August 2024.
| Photo Credit: SPECIAL ARRANGEMENT

In a rare initiative in Karnataka, Puttur City Municipal Council in Dakshina Kannada district has been converting wet waste into Bio Compressed Natural Gas (BioCNG) with the help of a private company. The BioCNG is being used to operate six vehicles of the municipality.

The BioCNG is generated by Krishna Muliya Green Energy LLP in a plant at Bannur.

Now, the municipality and Krishna Muliya Green Energy LLP are planning to sell surplus BioCNG to potential consumers.

Municipality Commissioner Madhu S. Manohar told The Hindu that the plant was set up by Krishna Muliya Green Energy LLP under Build, Own, Operate and Transfer (BOOT) model on civic land. The plant was financed and is being operated by the LLP. The firm will have to hand over the plant to the municipality after 40 years.

“The plant produced over 24,000 k.g of BioCNG since August, 2024,” the Commissioner said adding that it produced between 200 kg and 250 kg of gas daily. “Our target is to produce 350 kg of gas every day,” he said.

Mr. Manohar said that about 12 tonnes of wet waste is generated in the jurisdiction of the municipality daily. The municipality diverted 10 tonnes of wet waste for producing BioCNG. The remaining two tonnes of waste is not fit for use in the plant because it contains some mixed waste. Wet waste has to be segregated if it is to be used for generating gas. Hence, the two tonnes are being used for composting.

Krishna Narayana Muliya, Managing Director, Krishna Muliya Green Energy LLP, said that the firm joined hands with the municipality as a social service without commercial interest as the venture is not remunerative. “Preparations are on to sell the unused BioCNG to people,” Mr. Muliya said.

Retap Solutions Private Limitdd, Mangaluru has provided technical solutions for the project.

The Commissioner said that, with a growing population and increasing waste generation, Puttur city faces a mounting challenge in managing municipal solid waste, particularly biodegradable wet waste. Recognising the environmental and economic potential of organic waste, the municipality adopted innovative solutions to convert it into BioCNG, a renewable and eco-friendly energy source.

By leveraging cutting-edge technology, the municipality processes organic waste, such as food scrap, vegetable peels, and garden trimmings, into high-quality BioCNG. This not only helps in reduce the dependency on fossil fuels but also mitigates the harmful impact of improper waste disposal, such as greenhouse gas emissions and soil contamination.

“The initiative is the first of its kind among urban local bodies in Karnataka,” Mr. Manohar said.

“We have been getting enquiries from a few other urban local bodies in the State seeking details with the intention of replicating the process in their cities,” the Commissioner said.