My Science School

North Korea last month fired two short-range ballistic missiles into the sea in defiance of UN Security Council resolutions that ban such launches by the country. Some experts said North Korea's recent missile launches were aimed at laying pressure on the new Biden government in the U.S., which condemned the tests. The U.S. North Korea talks on curbing the latter's nuclear ambitions have been stalled for nearly two years due to disputes over the U.S. sanctions on the North. But what are ballistic missiles and why are their development condemned?

Capable of mass destruction

Ballistic missiles are short-, medium and long-range rocket-propelled weapon systems with the potential to carry and deliver weapons of mass destruction quickly and accurately. They follow a ballistic trajectory (a curved path) over most of their flight to deliver a payload (an explosive. weapon or nuclear device) intended to destroy a predetermined target. That means even after the missile burns up the fuel which propels it, it keeps moving and its direction remains unchanged. It follows a path determined by the speed of its launch and the influence of gravity on it which pulls it towards the Earth. So, it is gravity that eventually guides the missile to its target. Currently, over 30 countries are in possession of ballistic missiles.

Rules governing ballistic missiles

The proliferation of missiles has always been viewed as a threat to global peace and security. But, there is still no legally binding arrangement to deal with the issue of missiles. A number of multilateral regimes such as the Missile Technology Control Regime (MTCR) and the Hague Code of Conduct Against Ballistic Missile Proliferation (HCOC) exist to prevent missile proliferation. The voluntary MTCR was initiated in April 1987 by the G-7 countries (Canada, France, Germany, Italy, Japan, the UK and the U.S.) with the aim of limiting the spread of ballistic missiles that could be used in chemical, biological, and nuclear attacks by keeping vigil over transfer of missile equipment and technologies. The MTCR currently has 35 member countries, including India which became a member in 2016. Its activities are in line with the U.N.'s non-proliferation efforts. Countries are deterred from pursuing missile programmes either through sanctions or diplomatic dialogues. Though not legally binding, the MTCR expects its member countries to act responsibly and practise restraint with regard to export of items that could lead to missile proliferation.

The HCOC launched in 2002, urges all countries to show greater restraint in their own development of ballistic missiles and to reduce their existing missile arsenal. It has over 140 member countries who are expected to annually exchange information about their ballistic missile launch programmes and provide advance notice of any such launches.

When was it first used?

The first-ever usage of ballistic missiles can be traced to World War II, when the Nazi Germany used the V-2 long-range guided ballistic missiles to attack London. When the war ended, the U.S. with the help of the captured German scientists built its own intercontinental ballistic missiles capable of unleashing nuclear destruction. Not surprisingly, other countries too got their hands on the new technology.

 

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Four Indian pilots, who were selected to become astronauts to crew Gaganyaan, the country's first manned space mission, have returned after completing their one-year training course in Russia's Zvyozdny Gorodok city near Moscow. The contract for the training of Indian officers was signed between the Indian Space Research Organisation (ISRO) and Russian launch service provider Glavcosmos in June 2019. The four pilots of the Indian Air Force (IAF) include a Group Captain and three Wing Commanders, according to the IAF sources. The training began on February 10, 2020, but was temporarily interrupted due to the COVID-19 pandemic.

The ISRO said the astronauts will now receive module-specific training in India. They will be trained in crew and service module designed by the ISRO, learn to operate it, work around it and do simulations.

Meanwhile, the Indian space agency signed an agreement with the French space agency CNES to help prepare for the Gaganyaan mission and to serve as its single European contact in this domain. How will France help India in the mission? What is Gaganyaan all about?

What is Gaganyaan Mission all about?

Gaganyaan is a 10.000-crore manned space mission, which will launch three Indian astronauts (the fourth astronaut will be a backup) to circle Earth at a distance of about 300-400 km from the surface for up to seven days. If successful, India will become the fourth nation to send a person into space, after Russia, the U.S. and China,

The crew will be launched into space using an indigenous Geosynchronous Satellite Launch Vehicle Mark III (GSLV Mk-lll rocket), from the refurbished launchpad at Sriharikota. The ISRO will carry out two unmanned missions before the manned space flight.

The crew was expected to commence its journey in 2022, following the formal announcement of the Gaganyaan project in August 2018. But the ISRO stated in late 2020 that the Gaganyaan project will be "slightly delayed due to COVID-19. In a written statement to the Lok Sabha, Jitendra Singh, Union Minister of State for the Department of Space said. "First unmanned mission is planned in December 2021. Second unmanned flight is planned in 2022-23, followed by human space flight demonstration."

Who is leading the project?

V.R. Lalithambika, a specialist in advanced launcher technologies, is the Director of the Human Spaceflight Programme. She has worked on rocket technologies such as the Polar Satellite Launch Vehicle (PSLV) and the GSLV.

Why GSLV-MK III?

A launch vehicle that can carry heavy payloads into space is important for a human spaceflight project. ISRO'S GSLV Mk-ll, the country's heaviest rocket, is considered to be ideal as the 640-tonne and 43- metre-tall rocket can launch 10 tonnes of payload into low-Earth orbit, an altitude of 2.000 km or less above the planet. The crew module is likely to weigh in excess of 5 to 6 tonnes.

Whereas ISRO's main launch vehicle, the PSLV, which carried the Chandrayaan and Mangalyaan missions, weighs about 320 tonnes and can carry payloads up to two tonnes and to orbits of 600 km altitude from the Earth's surface, and hence is not suitable to send a crew into space.

How did the project take shape?

2004: The ISRO Policy Planning Committee made recommendations for a manned space mission 2006: Preliminary studies of Gaganyaan started under the generic name Orbital Vehicle.

2008: An initial design of a fully autonomous vehicle to carry two astronauts was finalised by March 2008 and was submitted to the Government of India for funding.

2009: A committee was formed to analyse the feasibility of the programme. The committee expressed support.

February 2009: The funding for the Indian Human Spaceflight Programme was sanctioned.

December 18, 2014: Successful testing of experimental flight of GSLV Mk-lll was carried out. The launch also involved the successful testing of an experimental crew module. Called the Crew module Atmospheric Re-entry Experiment (CARE), the spacecraft reentered the atmosphere at about 80 km altitude and landed in the sea near the Andaman and Nicobar Islands, from where it was recovered. June 5, 2017: First flight of GSLV Mk-lll was carried out. GSLV Mk-ill placed the country's heaviest satellite till date. GSAT19, into a precise orbit. With it India became a nation having its own indigenous cryogenic engine technology.

July 5, 2018: First successful flight of the crew escape system was carried out. The crew escape system is an emergency measure designed to quickly pull the crew module along with the astronauts to a safe distance from the launch vehicle in the event of a launch abort. A simulated crew module weighing about 3.5 tonnes was launched from Sriharikota. It reached 2.7 km into space before unfurling its parachutes and floating back to the Earth's surface. August 15, 2018: Prime Minister Narendra Modi promised manned mission before 2022.

May, 2020: The ISRO invited startups and private players to develop R&D solutions for food and medicine for the astronauts, support systems such as space suits, and anti-radiation and thermal protection technologies for spacecraft while returning to Earth.

What does the recent Indo France agreement on the mission mean?

According to news reports, the CNES will train India's flight physicians and CAPCOM mission (the Capsule Communicator, or CAPCOM) control teams in France. The agreement also provides for the CNES to support implementation of a scientific experiment plan on validation missions, exchange information on food packaging and nutrition, and the use of French equipment, consumables and medical instruments by Indian astronauts.

French equipment developed by CNES, tested and still operating aboard the International Space Station (ISS), will thus be made available to Indian crew members. The CNES will also be supplying fireproof carry bags made in France to shield equipment from shock and radiation.

What is Vyommitra?

Vyommitra is a robot, half-humanoid to be exact. It has been developed by the ISRO and it will accompany Indian astronauts on Gaganyaan. It will also be part of the uncrewed experimental Gaganyaan missions prior to the crewed spaceflight mission.

But what's the purpose? In the early years of space flight, there were concerns whether humans could mice, survive in space. So animals such as fruit flies, monkeys and cats were sent before the first human ventured into space to test the survivability of spaceflight.

But India will not fly animals into space. Instead, it will launch the robot. On the uncrewed mission, the robot will help the Indian space agency to understand what weightlessness and radiation can do to the human body during long durations in space.

While onboard the crewed mission. Vyommitra can detect and give out warnings if environmental changes within the cabin get uncomfortable to astronauts and change the air condition. It is programmed to speak Hindi and English and perform multiple tasks. It can mimic human activity, recognise other humans, and respond to their queries.

 

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Plastic bags. They are everywhere, aren’t they? If you go shopping in the mall, you end up with a number of them. If you buy some clothes from a store, they are given to you in plastic bags. Picking up some groceries from the road-side vendor? They hand it to you in small plastic bags. There’s no escaping plastic bags, really. And very few even try to…

For an item that is now present everywhere, it has a rather short history. While plastics had been around in the first half of the 20th Century, it was only in the 1950s that a process to produce high-density polyethylene was first figured out.

How to best use it?

Once that came about, some products made of plastics started to get a move on. Yet, companies were still trying to find out how best to utilise the new substance at hand and maximise their advantage.

Among these companies was a Swedish company called Celloplast, which had sold cellulose film. Finding themselves with these plastics, the company invested resources to identify better ways of using and selling it.

Packaging purposes

It was in 1960 that Celloplast filed for a U.S. patent for “tubing for packaging purposes”. Designed by a team of three employees, their idea was to lay flat a tube of plastic and seal it at regular intervals in order to create the bottom of a bag. Left open at the top, anything could be placed inside these bags, which then could be packaged.

By the time this patent made its way in March 1962, Sten Gustaf Thulin, one of the three employees, was onto a better idea that would further enhance their existing one. Instead of just sealing the bottom and leaving the top open, Thulin realised that punching out part of the plastic tubes at the top would create handles for these bags.

Thulin’s “bag with handle”

Celloplast filed a patent for Thulin’s idea in July 1962. On April 27, 1965, they received the U.S. patent for “Bag with handle of weldable plastic material”. Thulin’s idea, what is now often called the “T-shirt plastic bag”, is the design behind every plastic bag that we see these days.

As the years went by, plastic bags started replacing every other type of bag in existence. By the end of the 1970s, 80% of the bag market in Europe was controlled by plastic bags. They were then introduced in the U.S., where they were marketed aggressively as superior to existing alternatives.

Solution turns problem

When Thulin came up with the idea, he was hoping to protect the environment as well. Back then, paper bags were the most popular type of carrier bags. For these paper bags, they not only had to cut down a lot of trees, but they also require more energy and water to produce, all of which have an impact on the planet we reside in.

Thulin believed that his plastic bags, which were both lighter than paper bags and also more energy efficient to make, would be used repeatedly by everyone. Speaking to BBC in 2019, Raoul Thulin, son of Sten Gustaf, said that “the idea that people would simply throw these away would be bizarre” to his dad. He also mentioned that his father always carried one of these folded up plastic bags in his pocket in order to make sure he could reuse the same bag.

Somewhere along the way, however, these plastic bags became so convenient, easily accessible, and cheap that people started throwing them away after a single use. Even though they weren’t supposed to be single-use products, they ended up being that way.

Use, reuse, mend, recycle

While plastic pollution is a huge problem and one to which we don’t have sound answers yet, simply ditching plastic to other alternatives isn’t a great idea either as they too can have adverse effects, including climate change. Research suggests that in order to be as environmentally friendly as a single-use plastic bag that gets recycled, a paper bag needs to be used at least three times. As for bags that are made of cotton, which is an intensive crop requiring a lot of water, it would have to be used 131 times to have the same environmental impact as a single-use plastic bag that is recycled.

Though all this might make the simple choice of selecting a bag seem daunting and confusing, an easy way to navigate it might be using the bag that you already have over and again. Do this for as long as you can and when the bag breaks, try to repair it. And when the bag reaches a stage where it can no longer be mended either, make sure that you recycle the bag. Remember, if we all take these simple steps, we will be protecting our Earth a little better.

 

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Stunning pictures such as this one that show a birds-eye view of a region on the Earth's surface are so common these days that we hardly stop to think about how they are achieved. The advent of drones have led to a proliferation of such images as aerial photography has become more accessible than ever before.

The technique of photographing the Earth's surface, or even features of its atmosphere and hydrosphere, using cameras that are mounted on rockets, aircraft. Earth-orbiting satellites or any spacecraft in general is known as aerial photography. While the growth of aerial photography was fast-tracked after its application in military reconnaissance and intelligence gathering was identified, it has spilled over to many other fields as well.

Terrestrial mapping

Mapping remains an important use of aerial photography as terrestrial features can be well captured using this method. With satellite technology and interpretation using experts, aerial photography has made available crucial data on topography, geology, hydrology, soil, vegetation, ocean currents, fish resources, and many other areas.

A little-known German engineer named Alfred Maul played his part in the growth of aerial photography. Through his experiments in rocket photography at the start of the 20th Century, Maul pioneered aerial reconnaissance.

Born to a trader and his wife in 1870, Maul attended community schools in Poessneck and Dresden before graduating from the Conservatory of Dresden. Apart from being musically gifted and an excellent piano player, Maul turned out to be a professional engineer after studying at the engineering school in Reichenberg (now Liberec).

Multi-disciplinary Maul Even though he was listed as a civil engineer in the address register of Dresden, Maul dabbled in various fields with considerable success. The fact that he ended up with over 20 patents in mechanical engineering and contributed significantly to aerial photography is testament to it.

Maul was drawn towards the theoretical aspects of building a rocket apparatus to aid aerial photography in about 1900. He started his first tests by 1901 and was soon confronted by several obstacles - the parachute didn't work once, the rocket exploded in another instance, the camera shutter didn't release at times, and there were other times when it released at the wrong moment.

Photos taken laterally

Maul ticked each of these complications one by one off his list as he kept experimenting to enhance his device further. While the idea of taking such photos wasn't new, Maul was able to come up with an invention in which the photograph could be taken laterally or from the side of the instrument and not vertically or beneath the apparatus. This had particular advantages as the photo could be clicked during stable flight and hence were less blurred, and the camera could also be aimed at specific terrains.

Maul applied for his patent in the U.S. with the title Rocket apparatus for taking photographs in 1903 and obtained it on April 19, 1904. The primary use of the device had been for military reconnaissance, and by offering demonstrations, Maul was able to find takers for his invention.

Aircraft take precedence

Maul is believed to have experimented with these ideas from 1901 to 1912 with no evidence of having worked on it after this period. The timing couldn't have been worse as by the time the First World War made its way in 1914, aircraft became the vehicle of choice for aerial reconnaissance.

Even though Maul gained little for these efforts of his, his invention is among the first instrumented rockets, and with hindsight can be seen as a milestone in aerial photography. Thanks to Maul and the many others who followed, the technology in this field has progressed so fast in the 100-odd years since then, offering us stunning visuals of the Earth's surface.

 

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The Apollo 11 mission is among the best remembered space missions and will probably remain so for a long time. For it enabled human beings to set foot on our natural satellite, the moon, for the first time. Missions, both before and after this one, often pale in comparison, even though scientifically significant. Despite being a failed mission, Apollo 13 comes close in popularity to Apollo 11 as its story portrays the triumph of human will in adverse circumstances.

Doesn’t excite people

By the time the Apollo 13 mission was successfully launched on April 11, 1970, the space programme had become a bit of a bore for the average American. Apollo 11’s historic first was followed by the precise touchdown on the moon that was achieved by Apollo 12, leaving people wondering if money could be better spent solving issues here on Earth.

It therefore comes as no surprise that none of the major U.S. TV networks carried the prime-time television broadcast relayed by the crew aboard Apollo 13 on the evening of April 13. A few hours later, however, not just Americans, but people from around the world waited with bated breath for updates about Apollo 13.

Jim Lovell was the commander of Apollo 13 and in his fourth to space. He had two rookies in the form of command module pilot Jack Swigert and lunar module pilot Fred Haise for company. Swigert, in fact, was a last-minute replacement for Ken Mattingly. As Mattingly was exposed to German measles just days before launch and was the only one in the crew who did not have immunity, he had to make way for Swigert.

Odyssey and Aquarius

The command module of Apollo 13 – an orbiter named Odyssey – and the landing module, called Aquarius, were joined together by a tunnel. After conducting the TV broadcast on April 13, the astronauts activated Aquarius to check its systems as they were scheduled to enter the moon’s orbit the next day.

An explosion rocked Apollo 13 just as Lovell was moving back to Odyssey through the tunnel. Within seconds, pressure in one of the oxygen tanks of the spacecraft dropped to zero. This disrupted the supply of oxygen, water, electricity and light to the command module.

Lunar module turns lifeboat

Even as the astronauts hurried to find what happened, Swigert communicated their distress to mission control. When mission control asked them to say it again, Lovell repeated Swigert’s famous words: “Houston, we’ve had a problem here.”

Less than an hour after the explosion, the lunar landing mission was aborted, with the primary objective now to get the astronauts safely back to Earth. Mission controllers at Houston instructed the astronauts to move into Aquarius.

The lunar landing module, which was designed for transport from the command module to the lunar surface and back, suddenly found itself serving the purpose of a lifeboat that had to traverse a distance of over 3,20,000 km as the astronauts tried to make their way back to Earth. While Aquarius had enough power supply for two astronauts over 45 hours, it now had to support three men for at least 90 hours.

Ration necessities

Lovell, Swigert and Haise not only restricted the amount of water they drank, but also the electricity they consumed. Based on instructions from mission control, they also made a makeshift device to remove the excess carbon dioxide from the cabin. Using inputs from mission control, they also executed a five-minute engine burn that generated enough speed to get the spacecraft home-bound even as its power ran out.

Without a heat shield, Aquarius wasn’t equipped for re-entry to the Earth. Following three days of non-stop work on the part of engineers, flight controllers and NASA managers, the astronauts finally performed the process of powering up Odyssey once again. Once done successfully, the astronauts moved from the lunar module to the command module in preparation for re-entry.

On April 17, Apollo 13’s Odyssey re-entered Earth’s atmosphere. Following four minutes of radio silence, which seemed like years to the countless observers following the progress, the astronauts’ parachutes were spotted and they touched down safely on the water’s surface.

NASA’s investigation revealed that manufacturing and testing errors had led to the disaster, even though the worst was averted. Though the mission was effectively a failure, Lovell, Swigert and Haise were celebrated like heroes. As for Apollo 13, it remains one of the most famous space missions ever as it showcased collective human ingenuity and tenacity in the face of a life-threatening situation.

 

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A new study shows that butterflies evolved an effective way of cupping and clapping their wings to generate thrust that helps them avoid dangerous predators.

Researchers at Lund University in Sweden studied the aerodynamics of butterflies in a wind tunnel. During the upward stroke, the wings cup, creating an air-filled pocket between them. When the wings then collide, the air is forced out, resulting in a backward jet that propels the butterflies forward. The downward wing beat has another function: the butterflies stay in the air and do not fall to the ground.

This theory was described by researchers almost 50 years ago, but is only now being tested on read butterflies in free flight. It was commonly thought on that butterfly wings were aerodynamically inefficient, however, researchers disagree. “That the wings are cupped them together, makes the wing stroke much more effective. It is an elegant mechanism that is far more advanced than we imagined.”

These findings could help improve performance and fight technology in small drones.

 

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The European Space Agency (ESA) says that the “time has come” to put differently – abled people in space under the Parastonaut Feasibility Project. The International Paralympic Committee will advise the ESA on selection. Right now, recruitment is open to people with leg amputations, with marked differences in leg length or who are especially short. The ‘parastronaut’ chosen would be the first disabled astronaut in history. David Parker, ESA’s Director of Human and Robotic Exploration says “Representing all parts of our society is a concern that we take very seriously… Diversity at ESA should not only address the origin, age, background or gender of our astronauts, but also perhaps, physical disabilities.”

The International Paralympic Committee will advise the ESA on selection.

The move comes in light of a recent report by the Associated Press that only 65 of more than 560 people who have been to space were women of the 65, 51 were Americans. 

 

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Engineers at MIT have transformed spinach into sensors capable of detecting explosive materials. When spinach roots deter the presence of nitroaromatics in ground water, a compound found in explosives like landmines, engineered carbon nanotubes within the plant leaves emit a signal that is then read by an infrared camera, sending an email alert to the scientists.

This experiment is part of a technology known as ‘plant nanobionics’ which involves engineering electronic components and systems into plants, giving them new abilities.

“Plants are very good analytical chemists,” explains Prof. Michael Strano who led the research. “They have an extensive root network in the soil, are constantly sampling groundwater, and have a way to self-power the transport of that water up into the leaves. This is a novel demonstration of how we have overcome the plant/human communication barrier.”

Scientists believe this technology could help warn researchers about pollution and other environmental conditions. “Plants are very environmentally responsive. They know that there is going to be a drought long before we do. They can detect small changes in the properties of soil and water potential. If we tap into those chemical signaling pathways, there is a wealth of information to access,” says Strano.

 

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NASA astronauts and employees will be using Fitbit devices as part of a pilot programme that aims to use Fitbit in-app daily check-in and symptom logging to help prevent the spread of COVID-19. The Google-owned company said there is evidence that resting heart rate data and other key health indicators from wearables have the potential to identify illnesses such as COVID-19 before symptoms emerge. One thousand NASA employees performing mission-critical work at six locations across the U.S. will receive Fitbit Charge 4 devices and access to Fitbit’s Ready for Work Daily Check-In experience’.

The COVID-19 pandemic is far from over. Johns Hopkins' coronavirus-tracking map has recorded over 107 million cases of the disease globally, leading to more than 2.3 million deaths. Today, many workplaces and other organizations have turned to tech to try to curb the spread of the virus.  

This partnership is born out of those efforts. In December, npj Digital Medicine published findings from Fitbit demonstrating the consumer wearables could be key to predicting the onset of illness like COVID-19 by using health metrics like breathing rate, resting heart rate and heart rate variability (HRV).

“The pandemic has underscored the critical role that Fitbit can play in providing much-needed support to help people sleep better, eat better, move more and take control of their health and wellness, as well as the potential to identify illness from specific health metrics, which is especially important now during the COVID-19 crisis,” Amy McDonough, managing director and general manager of Fitbit Health Solutions at Google, said in a statement.

“We are proud to work with NASA to support its employees and give them access to Fitbit products and services to help them better understand and manage their health and well-being during the pandemic.”

 

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With the world's largest vaccination drive going on in the country, you may have heard people mention Co-WIN. What is it?

The government which launched the anti-coronavirus vaccination drive on January 16, 2021, by inoculating frontline and healthcare workers, has extended it in the next phase to senior citizens (those above 60 years) and those aged 45 or older with comorbidities (pre existing health conditions). How can they get vaccinated? First they should register themselves on the anti-coronavirus vaccine registration portal called COWIN

A mobile app

COWIN is a mobile app rolled out by the government to ensure smooth implementation of the vaccination process. Owned by the Ministry of Health and Family Welfare, COWIN is said to be an extension of the eVIN (electronic Vaccine Intelligence Network), which has been used in crucial immunisation programmes across the country. COWIN stands for COVID-19 Vaccine Intelligence Network. The COWIN system identifies target groups, registers beneficiaries, allots vaccine centres subject to availability, and keeps track of the beneficiaries. Not just that, it also keeps track of the vaccines at the national, State and district level on a real-time basis. With every detail uploaded on the digital platform, utilisation, wastage, and coverage of the vaccination campaign can be constantly monitored.

How to register

The COWIN app is meant for administrators, supervisors, and vaccinators, and not for us, the general public. People can register for the anti-COVID vaccination through the COWIN portal http:// www.cowin.gov.in and through the Aarogya Setu app (Remember this app was launched to detect contact tracing when the pandemic broke out?), which has been integrated with the COWIN app. Besides, there is a walk-in provision for people to get themselves registered and vaccinated at the nearest centre.

Registration on the COWIN portal opened on March 1. People need photo identification proof to register - they can use their Aadhaar card, Driving Licence, Voter ID, or PAN card, among others. In the initial days, the app faced some technical glitches. But it is said that they have been taken care of subsequently. Further, it is said that the personal data of beneficiaries stored on COWIN is secure and hence will not be available in the public domain.

The vaccines being administered in the country should be given in two doses. They are being provided free of cost at government vaccination centres, while at private centres, they cost Rs. 250 per dose.

 

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Human journey into space began in 1957, when the Soviet Union (today's Russia) launched Sputnik, the first ever artificial satellite. Since then, thousands of rockets have been launched, which have put into space numerous satellites, spacecraft, and space stations. Not all of them are functional today, nor has everything been brought back to Earth. Several of them, their parts, and random objects such as nuts and bolts are still up there as space junk. Worse, they are tumbling through space at a high speed putting functional satellites in Low Earth Orbit (LEO) at risk. There are fears that collisions between debris could set off a chain reaction, with the result that LEO would become unusable.

In 2007, China tested an anti-satellite missile by destroying one of its weather satellites. Two years later, an American and a Russian spacecraft accidentally collided. According to an estimate, these two events alone increased the amount of large debris in the LEO by about 70%. Space agencies have begun taking steps to mitigate the problem. A Japanese company launched one such initiative recently. Called Elsa-D, the mission intends to demonstrate a space debris removal system.

Mission Elsa-D

On March 22, 2021, a Soyuz rocket put 38 payloads into space. Among them was the ‘The End-of Life Services by Astroscale demonstration mission’ (Elsa- D), developed by a Japanese company called Astroscale. It is the world's first Commercial mission to demonstrate a space debris removal system. Elsa-D consists of two spacecraft: a 175-kg "servicer and a 17-kg client". Client is the fake debris that the servicer will have to release, grab, and repeat.

How does it work?

Astroscale's demo mission aims to test its magnet strategy. A magnetic plate has been built into both the servicer and the client. The mission was designed to separate both the components a few weeks after the launch. Once released the servicer will hunt the client down, latching on to it using the magnetic docking plate, then releasing the client for another capture practice.

If that basic manoeuver goes well, the task will become increasingly complex Astroscale will remotely instruct the components to tumble, spinning like a dead satellite normally would. That will force the servicer to assess its target and line up with the prototypes docking magnet

Eventually, the servicer will pull the "debris" towards the Earth's atmosphere where both the components will burn up. If such a technology were to be put to use, then future satellites should come built with this types of magnetic docking plate to enable removal once they become defunct and then?

Hundred million bits

 

Space debris refers to all the human-made objects such whole and abandoned satellites pieces of broken satellites deployed rocket bodies and other room objects such as tiny flecks of paint from spacecraft and event tools left behind by astronauts during space walk. Most of them orbit Earth and some even beyond it Some of the have made it to Venus and Man. Twenty tonnes of them have been found on the Moon, says NASA According to the European Space Agency, more than 2.400 dead satellites A computer generates artists impression of space junk. PHOTO: ESAVAFP and 100 million bits of debris are already circling Earth. And the debris keeps piling up as satellites have gotten smaller, cheaper, and easier to launch.

How are they monitored?

Scientists use radar to keep track of space debris. The US Space Surveillance Network keeps track of known orbital objects wing ground-based radar systems such as the TIRA Haystack and EISCAT radars and the Cobra Dane Telescopes and observatories such as the ESA Space Debris Telescope and the Goldstone provide additional data. As of 2020, the United States Space Surveillance Network was tracking more than 14,000 pieces of space debris larger than 10 on across. It is estimated that there are about 2.00,000 pieces between 1 and 10 and macros.

What are the risks?

In-orbit risks

• The damage can be as small as a dent on a shuttle window to the destruction of an entire satellite. In 1996, a French satellite was hit and damaged by debris from a French rocket that had exploded a decade earlier. Objects in LEO travel at speeds up to 10km/second, fast enough to cause significant damage to satellite, spacecraft or spacewalking astronauts. The rising number of space debris increases the potential danger to all space vehicles, especially to ones with humans aboard, the International Space Station (ISS), for instance.


• In 2020 alone, the ISS was manoeuvred away from space debris on three occasions, since a collision could endanger the astronauts on board. A number of space shuttle windows have been replaced because of damage caused by paint flecks.


• The density of the junk may become so great that it could hinder our ability to use weather satellites, and hence to monitor weather changes.

Debris that re-enters Earth

Space trash is often attracted by Earth's gravitational pull. It is pulled lower and lower until it finally reaches Earth's atmosphere. Most objects burn up when they enter Earth's atmosphere due to the compression of atmospheric gases, but larger objects can reach the Earth intact. But most of them fall into the ocean, simply because Earth is mostly covered by water. According to NASA website, an average of one catalogued piece of debris has fallen back to Earth each day over the last 50 years. But there have not been any significant damage. No one has ever been killed by re-entering space debris. People on Earth should avoid contact with the fallen debris, such as rocket parts, because of the possible presence of hazardous chemicals in them.

What is the solution?

• The solution involves steps to clean up the mess, mitigate damage, and avoid future debris. There are systems in place to track the debris and avert disasters. Various space organisations have been working on reducing the amount of trash by adopting better designs of rockets and other objects. For example, making rockets reusable could vastly cut down waste.


• The UK's TechDemosat-1 (TDS-1), launched in 2014, was designed in such a way that once its mission is over, a system, like a parachute, would drag the satellite to re-enter the atmosphere and bum up. Some satellites at the end of their lifecycle are made to fall out of orbit and bun up in the atmosphere, provided they still have fuel left in them for the descent Some satellites are sent even farther away from Earth.


• Technologies to remove space junk are also being developed. Cleaning the debris that already exists comes at a high cost, because it will take multiple trips to remove objects from space. Other proposals include the use of a laser to remove debris by changing their course and making them fall towards the atmosphere of Earth and later burn up.


• In December 2019, the European Space Agency awarded the first contract to clean up space debris. ClearSpace-1 is slated to launch in 2025. It aims to remove a 100-kg Vega Secondary Payload Adapter left by the rocket Vega flight W02 in an 800-km orbit in 2013. A "chaser" will grab the junk with four robotic arms and drag it down to Earth's atmosphere where both will burn up.

 

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Have you heard of the peak-end rule? A cognitive bias or psychological heuristic, it tells about how people remember past events. According to this rule, people judge an event largely based on intense positive or negative moments – the peaks – and the final moments of the experience – the end. This is counter-intuitive as one tends to think their memories of the past are based on the total sum or the average of every moment through the experience and not heavily weighted on a few instances.

A classic example of this rule is the Space Shuttle Challenger and how it is remembered by people these days. The Challenger was the second shuttle to reach space and spent over 62 days in space. It hosted the first space-walk of the space shuttle programme and carried the first American woman and first African-American astronauts into space. Even though it achieved all this and more through nine successful missions, the first thoughts for almost anyone who recollects about it is the 10th mission that ended in a disaster.

Test vehicle turns space shuttle

When the construction of the Challenger began in November 1975, it was intended to be a test vehicle. Nearly four years on, however, NASA decided to convert the test vehicle to a spacecraft, making it the second in the shuttle fleet, after Columbia.

The task of converting a test vehicle to a space shuttle took two years, and it was only in October 1981 that the work was completed. While the Challenger was expected to go to space in January 1983, technical malfunctions pushed the date further.

First launch delayed

First, a hydrogen leak was discovered by NASA during a flight readiness test. Next, during a second test, the cracks in the engine that were causing the leak were identified. Then, there was a delay due to a problem with the Tracking and Data Relay Satellite (TDRS) that the first Challenger mission was scheduled to release.

Finally, on April 4, 1983, Challenger was launched successfully on mission STS-6. The crew members set the TDRS free. The TDRS became part of a series of satellites that was used by astronauts to communicate with the controllers on Earth. American astronauts Story Musgrave and Donald Peterson then performed the first space-walk of the shuttle programme and also used the Extravehicular Mobility Unit (EMU) in the process for the first time.

A number of firsts

When the Challenger was launched again for STS-7 mission in June 1983, Sally Ride became the first American woman astronaut in space. The STS-8 mission witnessed American astronaut Guion Bluford reach space, thereby becoming the first African-American to achieve the feat.

During the STS-41G mission in 1984, Ride and Kathryn Sullivan rode the Challenger. This was the first time two women flew on one mission. This mission also saw Marc Garneau become the first Canadian in space.

The STS-41C mission that took place in April 1984 featured the first astronaut repair of a satellite. American astronaut George Nelson flew over to the non-functional Solar Maximum Mission (SMM) satellite, docked with it, and stopped its spin.

The remaining crew members on Challenger then plucked the satellite from space and brought it into the payload bay. Nelson then repaired the satellite along with fellow American astronaut James van Hoften, before releasing it back into space. The SMM satellite functioned properly till December 1989, when it burned up in the atmosphere.

Challenger disaster

The Challenger flew its 10th mission on January 28, 1986. Just 73 seconds after launch, however, the Challenger blew up in space, killing all seven on board.

A commission was set up, and the technical causes of the accident were determined. Issues such as the need to go ahead with the launch on such a cold day (the technical issue might not have happened if not for the low temperatures) were raised, and the safety and accountability culture of the entire workforce was changed. The Challenger might be best remembered for the disaster that unfolded in the 10th mission, but the accident also changed the way NASA functioned forever.

 

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The Big Bang theory is really famous. No, this isn’t about the American sitcom that shares the same name and is also extremely popular. This is about the theory that explains our origin. This means that the Big Bang theory is the leading explanation about how the universe began.

A cosmological model of the observable universe, the Big Bang theory, in its simplest form, says that the universe as we know it today began with a small singularity. This single point expanded, stretched, and inflated over the next 13.77 billion years to grow as large as we know it right now.

Alternate explanations exist

While the theory has won over most of the astronomical community, there are still others who believe in alternate explanations. There was a time – years after the theory had first been suggested and didn’t even go by this name – when the Big Bang theory was also perceived as an alternate explanation for the origin of the universe. In fact, the term “Big Bang” was coined by someone who was firmly against the idea. The credit for naming the theory goes to English scientist Fred Hoyle.

Born in 1915 in Yorkshire, England, Hoyle was educated in Cambridge before spending six years working on radar development with the British Admiralty during World War II. Returning to Cambridge as a lecturer in 1945, he announced the steady-state theory of the universe three years later, in collaboration with astronomer Thomas Gold and mathematician Hermann Bondi. According to this theory, the expansion of the universe and the creation of matter were interdependent. The “primeval atom”

Questions about the origin of the universe have been probed by scientists through centuries. It gathered momentum in the 20th Century and was bolstered further when American astronomer Edwin Hubble brought experimental observations regarding the constant expansion of the universe. The idea of the Big Bang theory was also first suggested around that time by Belgian priest and cosmologist Georges Lemaitre. Lemaitre proposed that the universe had begun from a single “primeval atom” by thinking back on Hubble’s evidence for expansion.

So when Hoyle delivered a lecture on The Third Programme, a broadcast by BBC radio, on March 28, 1949, he naturally tried to champion his cause. At one point during this show, when Hoyle was trying to distinguish the opposing theory with his own, he made the following statement: “We now come to the question of applying the observational tests to earlier theories. These theories were based on the hypothesis that all the matter in the universe was created in one big bang at a particular time in the remote past. It now turns out that in some respect or other all such theories are in conflict with the observational requirements.”

Controversial statement

The statement has since become controversial with many observers believing that the term “big bang” was coined in a derogatory way. The fact that Hoyle himself has clarified that he had no such intentions and was merely using it to help listeners invoke an image as it best described the idea hasn’t made headway either. Regardless, this is accepted as the first usage of the term “big bang” to describe the theory and the name has stuck to it.

Research in the second half of the 20th Century and the identification of cosmic microwave background (CMB) radiation in particular further strengthened the case of the Big Bang theory. Even though this debunked the original model of the steady-state theory and it slowly went out of favour among cosmologists, Hoyle remained a staunch supporter of it, tweaking it where he could to try to fit in the new evidence.

Hoyle might be best remembered for coining the term “big bang” and his strong refusal of the theory while defending his own, but his greatest contribution came in 1957 when he revealed through his research the stellar origins of the elements from which the universe, solar system, and our bodies are made. The fact that his close collaborator in this work, U.S. physicist Willy Fowler, was awarded the 1983 Nobel Prize in Physics for this research while Hoyle was outright ignored continues to be hotly debated till this day and is a story in its own right.

 

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The atomic bombs dropped over Hiroshima and Nagasaki in Japan towards the end of World War II continues to divide opinion to this day. While one side argues that the use of these weapons hastened the end of the war, the other side states that the damages done with these far outweigh any gains made.

The Fat Man atomic bomb was dropped over Nagasaki on August 9, 1945. Built with a solid plutonium core, Fat Man was the second (following Little Boy that was dropped at Hiroshima on August 6, 1945) of the only two nuclear weapons that have been used in warfare. The plutonium at its core had been discovered less than five years ago. Two of its discoverers, Glenn Seaborg and Edwin McMillan, went on to win the Nobel Prize in Chemistry in 1951 “for their discoveries in the chemistry of the transuranium elements”.

California connect

Born in Michigan in 1912, Seaborg moved with his family to California at the age of 10. He did his schooling in Los Angeles, received a bachelor’s degree from the University of California, Los Angeles, in 1934, and a Ph.D in Chemistry from the University of California, Berkeley, in 1937.

McMillan was born in California in 1907 and obtained his education in that State. He attended the California Institute of Technology, where he received his B.Sc. and M.Sc. degrees, before transferring to Princeton University for his Ph.D. in 1932.

Seaborg and McMillan, along with Arthur Wahl and Joseph Kennedy, discovered plutonium in December 1940 at Berkeley, California. By bombarding uranium-238 with deuterium nuclei (alpha particles) that had been accelerated in a cyclotron device, they were able to create neptunium-238 with a half-life of two days. The neptunium produced decayed by beta emission to form plutonium-238.

"Greatest scale-up"

In a matter of months, the chemical element with atomic number 94 was conclusively identified and its basic chemistry was shown to be similar to that of uranium. Once its potential as a source of nuclear energy had been identified, its extraction was scaled up from ultramicroscopic laboratory amounts to that required for a nuclear plant. Seaborg had called it “surely the greatest scale-up factor [10 billion] ever attempted” and they succeeded at it.

While the initial amounts of the element produced was invisible to the eye, a few millionths of a gram – enough to see and weigh – had been produced by 1942. By the time the bomb exploded in Nagasaki, the Americans had several kilograms of weapons-grade plutonium.

Klaproth's way

It was on March 21, 1942 that the element was given the name plutonium. When German chemist Martin Klaproth discovered uranium, which has an atomic number 92 and is the heaviest element existing in nature, in 1789, he had named it after the planet Uranus. When McMillan discovered the element with atomic number 93, also in 1940, he had named it neptunium, after the planet Neptune. Following from the two previous elements uranium and neptunium, the element with atomic number 94 was named plutonium, after Pluto (then a planet, now a dwarf planet).

Both McMillan and Seaborg contributed immensely to the chemistry of the transuranium elements (chemical elements with atomic numbers greater than 92, the atomic number of uranium). Apart from discovering neptunium and plutonium, McMillan also contributed to the mapping of additional heavy elements and isotopes. Seaborg was not just the co-discoverer of plutonium, but all further transuranium elements up to element 102.

Powers a mission to Pluto

As for plutonium, it was first used for destruction, as already mentioned. While it is still used in making nuclear weapons, it is also indispensable in the development of nuclear power. Plutonium has also been pivotal in the Space Age as it was put to use in the Mars Curiosity Rover and the New Horizons spacecraft. When the New Horizons made its way to Pluto, plutonium – an element named after the dwarf planet – served as its source of energy.

 

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