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The satellite has been designed to conduct a landmark survey of the world's oceans, lakes, and rivers from space for the first time.

NASA, the U.S. space agency, recently launched a satellite called SWOT. What is its objective and how will it help us? Let's find out.

Its mission

SWOT, short for the Surface Water and Ocean Topography satellite, was recently launched from California to make a comprehensive survey of the world's oceans, rivers, and lakes from space for the very first time. Dubbed a "revolution in hydrology", SWOT, an SUV-sized satellite flying at a height of 890 km, will offer an unprecedented, clear view of the water bodies, while tracking the rise in sea levels, as well as rivers, lakes, and reservoirs. The satellite is expected to offer key insights into how these bodies of water influence climate change and factors such as how much more heat and carbon dioxide oceans can absorb. Oceans are estimated to have absorbed more than 90% of the excess heat trapped in Earth's atmosphere caused by human-induced greenhouse gas emissions. With climate change accelerating, some regions are experiencing extreme droughts. while others extreme floods, along with changing precipitation patterns. According to researchers, the observations of SWOT will improve our understanding of how water moves around Earth, its circular currents in oceans, etc. This will help predict floods in areas where there is too much water, and manage water in places that are prone to drought.

How will it work?

The global water survey satellite will measure the height of water in freshwater bodies and the ocean on more than 90% of Earth's surface - which it will track at least once every 21 days. Researchers will be able to get data on millions of lakes, rather than the few thousands currently visible from space. The technology employed by SWOT is called KaRin, a Ka-band radar interferometer. The radar sends down a signal which is reflected back by the water surface. This echo is received by two antennas, resulting in two sets of data providing high accuracy for water detection and resolution. The data, compiled from the radar sweeps of the planet, will be used to bolster weather and climate forecasts and aid in managing scarce freshwater supplies in drought-stricken areas.

Who developed it?

The satellite is a billion-dollar project developed jointly by NASA and France's space agency CNES, with contributions from the Canadian space agency and the U.K. space agency. It was carried onboard a spacex Falcon-9 rocket from the Vandenberg U.S. Space Force Base. SWOT will start collecting scientific data in about six months time after undergoing checks and calibrations. The satellite's components were built primarily by NASA's Jet Propulsion Laboratory near Los Angeles and CNES.

According to SWOT'S project head at CNES, Thierry Lafon, the mission is meant to last for three-and-a-half years, but could be extended. The U.S. and French space agencies have worked together in the field for over three decades. An earlier satellite developed by the two agencies, TOPEX/Poseidon, improved understanding of ocean circulation and its effect on global climate. It also aided the forecast of the 1997-1998 El Nino weather phenomenon.

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Researches create lightweight flexible mirrors that can be rolled up during launch and reshaped precisely after deployment.

Mirrors are a significant part of telescopes. When it comes to space telescopes, which have complicated procedures for launching and deploying, the primary mirrors add considerable heft, contributing to packaging difficulties.

Researchers have now come up with a novel way of producing and shaping large, high-quality mirrors. These mirrors are not only thinner than the primary mirrors usually employed in space-based telescopes, but are also flexible enough to be rolled up and stored inside a launch vehicle.

Parabolic membrane mirror

The successful fabrication of such parabolic membrane mirror prototypes up to 30 cm in diameter have been reported in the Optica Publishing Group journal Applied Optics in April. Researchers not only believe that these mirrors could be scaled up to the sizes required in future space telescopes, but have also developed a heat-based method to correct imperfections that will occur during the unfolding process.

Using a chemical vapour deposition process that is commonly used to apply coatings (like the ones that make electronics water-resistant), a parabolic membrane mirror was created for the first time. The mirror was built with the optical qualities required for use in telescopes. A rotating container with a small amount of liquid was added to the inside of a vacuum chamber in order to create the exact shape necessary for a telescope mirror. The liquid forms a perfect parabolic shape onto which a polymer can grow during chemical vapour deposition, forming the mirror base. A reflective metal layer is applied to the top when the polymer is thick enough, and the liquid is then washed away.

Thermal technique

The researchers tested their technique by building a 30-cm-diameter membrane mirror in a vacuum deposition chamber. While the thin and lightweight mirror thus constructed can be folded during the trip to space, it would be nearly impossible to get it into perfect parabolic shape after unpacking. The researchers were able to show that their thermal radiative adaptive shaping method worked well to reshape the membrane mirror.

Future research is aimed at applying more sophisticated adaptive control to find out not only how well the final surface can be shaped, but also how much distortion can be tolerated initially. Additionally, there are also plans to create a metre-sized deposition chamber that would enable studying the surface structure along with packaging unfolding processes for a large-scale primary mirror.

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As the UN observes World Sustainable Transport Day on November 26, we take a look at what it means for Indian cities

All of us hate traffic jams. A person living in Mumbai spends an average of 9 days every year just being stuck in traffic, according to the India Traffic Report. 2019. There is a lot that citizens, like you and me, can do to change this Sustainable transport, according to the United Nations, can ease the pain of commuting through cities for everyone, including those with special needs.

Public transport

There are over 34 crore motor vehicles on Indian roads now, compared to a mere 14 crore in 2011 While the number of vehicles keeps growing meterorically, there aren't enough roads and parking spaces to accommodate all of them. The result -long winding traffic craints, parking problem , and a spike in road accidents.

At least one road accident was reported within every three minutes in India in 2022. A total of 1.68 lakh lives were lost. Despite all the data, faster bikes and bigger SUVs continue to be the aspirational purchases for the indian public, encouraged by loans and regulatory easements provided by the government. Mobility experts say public transport is the one and only panacea to this problem. it will help reduce road accidents, reduce carbon emissions, and resolve the space crunch that we are facing on roads and parking lots. But in the current form, public transport in India is plagued by many challenges.

Challenges to public transport. While policymakers keep pushing us to use public transport regularly, the fact remains that most of our casting systems are already full and overburdened. The Mumbai local trains, for instance, carry a whopping 80 lakh passengers a day By comparison, the local trains in Chennai ferry about 25 lakh Cities invested heavily in metro mil to reduce the burden on existing systems, and provide connectivity to new areas. While the public uptake has been encouraging, last-mile connectivity remains a challenge Last-mile connectivity means ensuring passengers have a reliable mode of commute from metro stations to their final destination. Providing rental or free cycles, ensuring metro stations are located near bus stands, commercial junctions, providing shuttle bus services, are some options that are being explored for last-mile connectivity on a trial-and-error basis. While these efforts are yet to bear fruit, lessons are being learnt across cities for implementation on a wider scale.

Pedestrians ignored

 Indian cities are fast becoming a nightmare for pedestrians. The Indian Road Congress has clearly laid out guidelines on the size of footpaths to be laid based on the size and category of roads. However, these norms are constantly flouted. Houses cutting into footpaths to build driveways and shops and illegally parked vehicles encroaching walking spaces are a common sight across our cities today.

A long-term study by IIT Madras showed that between 2009 and 2017, 80% of road accidents in Chennai involved pedestrians on footpaths or at road crossings. Since then, Chennai has tried to popolarise the concept of pedestrian plazas, by promoting big, dedicated walkways in various parts of the city. The initiative has been reasonably successful.

Electric vehicles

After walking and public transport, electric vehicles are the next best bet. While they do not remote universal access, they do mitigate the impact of vehicular and public transport, electric vehicles are the next best bet. While they do not promote universal access, they do mitigate the impact of vehicular pollution on the environment. Still, concerns remain as most of the electricity generated today in the country comes from burning dirty coal. The disposal of EV batteries-which are toxic to the environment is also a concern.

Sustainable transport is about building systems that can be used by anybody and everybody. It has to be affordable for the poor, accessible for the disabled, and seamless for the busy office-goers. As citizens, it is our duty to push the envelope with policymakers to make sustainable transport a reality in our cities.

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Researchers have succeeded in printing robotic hands with bones, ligaments and tendons for the first time. Using a new laser scanning technique, the new technology enables the use of different polymers.

Additive manufacturing or 3D printing is the construction of a 3D object from a 3D digital model. The technology behind this has been advancing at great pace and the number of materials that can be used have also expanded reasonably. Until now, 3D printing was limited to fast-curing plastics. The use of slow-curing plastics has now been made possible thanks to a technology developed by researchers at ETH Zurich and a MIT spin-off U.S. start-up, Inhabit. This has resulted in successfully 3D printing robotic hands with bones, ligaments and tendons. The researchers from Switzerland and the U.S. have jointly published the technology and their applications in the journal Nature.

Return to original state

 In addition to their elastic properties that enable the creation of delicate structures and parts with cavities as required, the slow-curing thiolene polymers also return to their original state much faster after bending, making them ideal for the likes of ligaments in robotic hands.

The stiffness of thiolenes can also be fine-tuned as per our requirements to create soft robots. These soft robots will not only be better-suited to work with humans, but will also be more adept at handling delicate and fragile goods.

Scanning, not scraping

In 3D printers, objects are typically produced layer by layer. This means that a nozzle deposits a given material in viscous form and a UV lamp then cures each layer immediately. This method requires a device that scrapes off surface irregularities after each curing step.

While this works for fast-curing plastics, it would fail with slow-curing polymers like thiolenes and epoxies as they would merely gum up the scraper. The researchers involved therefore developed a 3D printing technology that took into account the unevenness when printing the next layer, rather than smoothing out uneven layers. They achieved this using a 3D laser scanner that checked each printed layer for irregularities immediately.

This advancement in 3D printing technology would provide much-needed advantages as the resulting objects not only have better elastic properties, but are also more robust and durable. Combining soft, elastic, and rigid materials would also become much more simpler with this technology.

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