• The International Space Station (ISS) is a habitable artificial satellite in low Earth orbit that serves as a microgravity research laboratory. It is the largest artificial object in space and the largest international space project in history, involving five participating space agencies: NASA (United States), Roscosmos (Russia), JAXA (Japan), ESA (Europe), and CSA (Canada).
• The ISS was constructed in space over 13 years, with the first module, Zarya, launched on November 20, 1998. The last module, Poisk, was launched on December 10, 2016. The ISS has been continuously crewed since November 2000 and has hosted crews from 21 different countries.
• The ISS is used to conduct scientific research in a variety of fields, including astrobiology, astronomy, meteorology, physics, and materials science. It has also been used to develop new technologies, such as water recycling systems and solar panels.
• The ISS has six sleeping quarters, two bathrooms, a gym, and a 360-degree view bay window. It measures 109 meters (357 feet) end-to-end, and its solar array wingspan is also 109 meters. The ISS orbits Earth 16 times in one day, every 90 minutes to be precise, at a speed of 8 kilometres (5 miles) per second.

3. Astronaut Activities on the ISS

• Astronauts aboard the International Space Station (ISS) primarily engage in scientific experiments, focusing on research that cannot be conducted on Earth. These experiments cover various fields and contribute to scientific breakthroughs.
• Regular spacewalks are undertaken by ISS astronauts to install new components, such as robotic arms, and to perform maintenance tasks. This includes inspecting and repairing damage caused by space debris.
• Due to the effects of microgravity on the human body, astronauts adhere to a strict health regimen. This includes workouts on specially designed machines like treadmills for a minimum of two hours a day.
• As researchers focus on prolonged human habitation in space, ISS astronauts contribute to our understanding of the effects of microgravity. Daily exercise routines are not only for astronaut health but also aid scientific investigations into the potential long-term impacts on the human body.

4. Scientific Discoveries Benefiting Earth

• Astronauts conduct experiments on themselves, monitoring general health, nutrition, and the effects of solar radiation. Scientific breakthroughs from these studies have contributed to our understanding of diseases like Alzheimer's, Parkinson's, cancer, asthma, and heart disease.
• Discoveries on the ISS have directly benefited drug development on Earth. The unique conditions of microgravity allow researchers to study cell behaviour more closely resembling that inside the human body.
• Experiments on the ISS have led to advancements in water purification systems, crucial for sustaining life in space. These innovations have practical applications on Earth, improving water purification technologies.
• Research on the ISS has provided methods to mitigate muscle and bone atrophy caused by extended periods in microgravity. These findings have implications for developing countermeasures to address similar health challenges on Earth.
• Scientific experiments on the ISS have contributed to innovations in food production. These advancements are essential for developing sustainable and efficient food production systems for long-term space missions and have practical applications on Earth.

5. Future of the ISS

• Plans for the future of the ISS faced uncertainty with Russia's invasion of Ukraine, leading to disruptions in international collaborations. Russia's decision to leave the ISS and pursue its own space station further added complexity to the situation.
• New and established spacefaring nations, including Japan, China, India, and the United Arab Emirates, express interest in independent space exploration, marking a shift in the landscape of international collaboration.
• While the US and Europe have expressed commitment to the ISS until 2030, discussions about a post-ISS era are underway. NASA's Artemis program focuses on lunar exploration, while the European Space Agency (ESA) plans the development of a new space station named Starlab.
• The phrase "watch this space" takes on new significance as the ISS navigates geopolitical challenges and evolving ambitions in space exploration. Plans for lunar missions and new space stations signal a transformative era in human space exploration.

6. Conclusion

GLOBAL WARMING

1. Context

2. The difference in Temperature rise

• Temperature rises over land is much higher than over oceans. Overland the annual mean temperatures have risen by as much as 1.59 degree Celsius since preindustrial times, according to the latest report of the Intergovernmental Panel on Climate Change.
• Oceans, in contrast, have warmed by about 0.88 degree Celsius. The warming trends over the Indian region are very different.
• An assessment of climate change over the Indian subcontinent, published by the Ministry of Earth Sciences in 2020, said annual mean temperatures had risen by 0.7 degree Celsius from 1900.
• This is significantly lower than the 1.59 degree Celsius rise for land temperatures across the world. It could give the impression that the problem of climate change in India was not as acute as in other parts of the world. But that is not entirely accurate. 

3. Why is warming over India is lower?

• The relatively lower rise in temperatures over India is not a surprise. Also, India is not a special case. The increase in temperatures is known to be more prominent in the higher altitudes, near the polar regions, than near the equator.
• This is attributable to a complex set of atmospheric phenomena, including heat transfers from the tropics to the poles through prevailing systems of air circulation. India happens to be in the tropical region, quite close to the equator.
• A substantial part of the difference between the temperature rise over India and that over the entire world can be explained by understanding what the different numbers represent. 
• The planet as a whole has warmed by 1.1 degree Celsius compared with preindustrial times.
• But, as mentioned earlier, this is just the average. Different regions have seen very different levels of warming.
• The polar regions, particularly the Arctic, have seen significantly greater warming. The IPCC report says the Arctic region has warmed at least twice as much as the world average.
• Its current annual mean temperatures are about 2 degrees Celsius higher than pre-industrial times. Some other studies suggest the Arctic could be warming even faster.
• Again, this happens because of a variety of reasons, including the processes mentioned earlier. Another prominent cause is what is known as the albedo effect, or how much sunlight a surface reflects. The ice cover in the Arctic is melting, because of which more land or water is getting exposed to the Sun.
• Ice traps the least amount of heat and reflects most of the solar radiation when compared with land or water.
• More recent research suggests that the higher warming in the polar region could be attributed to a host of factors, including the albedo effect, changes in clouds, water vapour, and atmospheric temperatures.
• The warming in the polar regions accounts for a substantial part of the 1.1-degree Celsius temperature rise over the entire globe. 

4. Higher warming over land than oceans

• However, the 0.7 degree Celsius temperature rise over India has to be compared with the warming seen over land areas, not the entire planet.
• As mentioned, land areas have become warmer by 1.59 degree Celsius. Land areas tend to get heated faster and by a larger amount, than oceans.
• Daily and seasonal variations in heating over land and oceans are usually explained in terms of their different heat capacities. Oceans have a higher capacity to cool themselves down through the process of evaporation.
• The warmer water evaporates, leaving the rest of the ocean relatively cooler. However, longer-term enhanced heating trends over land have to be attributed to other, more complicated, physical processes involving land-ocean-atmospheric interactions.

5. Impact of Aerosols

• Aerosols refer to all kinds of particles suspended in the atmosphere. These particles have the potential to affect the local temperature in multiple ways.
• Many of these scatter sunlight back, so that lesser heat is absorbed by the land. Aerosols also affect cloud formation.
• Clouds, in turn, have an impact on how much sunlight is reflected or absorbed.
  Aerosol concentration in the Indian region is quite high, due to natural as well as man-made reasons.
• Due to its location in the tropics and the arid climate, India is no stranger to dust. But it also happens to be experiencing heavy pollution right now.
• Emissions from vehicles, industries, construction, and other activities add a lot of aerosols to the Indian region. A reduction in warming could be an unintended but positive side effect.

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