International Space Station

The International Space Station (ISS) is a remarkable space station orbiting Earth in low Earth orbit. It is the result of an international effort led by five major space agencies: NASA from the United States, Roscosmos from Russia, ESA from Europe, JAXA from Japan, and CSA from Canada. The ISS is the largest human-made structure in space and the first space station built through international cooperation. Since November 2, 2000, it has been home to humans continuously, marking the longest ongoing human presence in space.

Orbiting about 400 kilometers above our planet, the ISS travels at incredible speeds, completing a full orbit around Earth roughly every 90 minutes. It is as large as a football field, with enough room inside for around thirty people to live and work. The station serves as a unique laboratory where scientists perform experiments in microgravity and study the effects of living in space on humans and nature. The ISS has welcomed visitors from 26 different countries, showing how countries can work together for peaceful scientific discovery.

Conception

The International Space Station (ISS) began as an idea to build a space home where scientists from many countries could work together. This project brought together five space agencies: NASA from the United States, Roscosmos from Russia, ESA from Europe, JAXA from Japan, and CSA from Canada. Their goal was to create the first space station built, kept, and lived on through teamwork, making it the biggest human spacecraft ever made.

Purpose

The International Space Station (ISS) was created to serve as a research laboratory, an observatory, and a factory in low Earth orbit. It also helps prepare for future missions to the Moon, Mars, and asteroids. Over time, its roles expanded to include commercial, diplomatic, and educational purposes.

The ISS is a platform for scientific research, with power, data, and crew support for experiments. Research covers many fields, such as astrobiology, astronomy, physical sciences, and human health. One famous experiment is the Alpha Magnetic Spectrometer, which searches for dark matter. The space environment is harsh, but the ISS helps scientists study how space affects living things and the human body. This research is important for future long-term space travel.

International co-operation

The International Space Station is the most complex space project ever, involving five space agencies and fifteen countries working together. It started with an agreement in 1998 that set the rules for this big team effort. Many other agreements followed to handle different parts of the work, like making sure everyone follows the same rules when they visit.

Brazil was invited to join too, but couldn’t finish its part because of money problems and changed its mind in 2007. After the war in Ukraine began in 2022, some people worried that Russia might stop working with the others. But NASA said they have other ways to keep the space station moving if needed.

Construction

Main article: Manufacture of the International Space Station

Main articles: Assembly of the International Space Station and List of ISS spacewalks

The International Space Station was built through teamwork from many countries. Different parts were made in various places, such as Moscow for the Russian pieces and Huntsville, Alabama for many American parts. These pieces were carefully put together in space.

The building of the station started in November 1998. At first, two main pieces, called Zarya and Unity, were joined together. Over time, more rooms and tools were added by astronauts using special spacewalks and robotic arms. Even though there were some pauses, like after the loss of a space shuttle in 2003, the station kept growing. Today, it has many modules from different countries, making it a huge home for astronauts to live and work in space.

Structure

The International Space Station (ISS) is built in a way that allows pieces, called modules, to be added or removed. This makes the station flexible and adaptable.

Pressurised modules

The ISS has several main modules where astronauts live and work.

• Zarya: The first part of the ISS, launched in 1998. It provided power and storage.
• Unity: Connects the Russian and U.S. parts of the station.
• Zvezda: The core of the Russian section, launched in 2000. It serves as living quarters and control center.
• Destiny: The U.S. laboratory for scientific research, launched in 2001.
• Quest Joint Airlock: Allows astronauts to perform spacewalks.
• Poisk: A secondary airlock and docking port for Russian spacecraft.
• Harmony: Connects the U.S., European, and Japanese modules.
• Tranquility: Contains life-support systems and exercise equipment.
• Columbus: The European Space Agency’s science laboratory.
• Kibō: Japan’s research module.
• Cupola: An observation module with large windows.
• Rassvet: Used for storage and docking.
• Leonardo: Provides storage space for supplies.

Unpressurised elements

The ISS also has external parts that aren’t pressurised:

• Integrated Truss Structure: Holds solar arrays and radiators.
• Robotic arms: Help move modules and perform tasks.
• External Stowage Platforms: Store spare parts.
• ExPRESS Logistics Carriers: Hold experiments and equipment.

Former module

• Pirs: The Russian airlock, removed in 2021 to make space for new modules.

Planned components

• Axiom segment: A commercial module planned to attach to the ISS, possibly becoming a future space station.
• US Deorbit Vehicle: A spacecraft to bring the ISS down safely after its mission ends.

Cancelled components

Some planned modules were cancelled due to budget or redesign reasons, such as the US Centrifuge Accommodations Module and the Russian Science Power Platform.

Main article: Axiom Station

Onboard systems

The International Space Station (ISS) has important systems to keep the air, water, and power working for the crew. The Zvezda module in the Russian part handles many of these systems, with extra help from the US modules. The Nauka laboratory also has its own life-support systems.

The ISS creates its own oxygen using special devices, and it removes carbon dioxide and other gases with filters. The station gets power from large solar panels that stretch out like wings. These panels can turn to follow the Sun, making the most of sunlight. The solar panels power the station and its experiments, and extra power is stored in batteries when the station is in Earth’s shadow. The station also has systems to keep its temperature just right, using special radiators to send heat into space.

Communication is very important for the ISS. The station uses many radios to talk to mission control on Earth and to other spaceships. Astronauts use laptops to control the station and do their work. These laptops are special because they work with the station’s power and stay cool in space. The crew can also use the internet to send emails and watch videos during their free time.

Operations

Each permanent crew on the International Space Station (ISS) is given an expedition number. These expeditions last up to six months, from launch until undocking. Initially, crews had three members, but after the Space Shuttle Columbia accident, crews were reduced to two to ensure the station could be maintained. Once the Shuttle returned to flight, crew sizes grew again, reaching six around 2010. With the introduction of larger commercial spacecraft in 2020, the crew size increased to seven.

Oleg Kononenko holds the record for the longest time spent in space at the ISS, accumulating nearly 1,111 days over five missions. Peggy Whitson has spent the most time in space of any American, with over 675 days in space during her expeditions and Axiom missions.

Orbit, debris and visibility

The International Space Station (ISS) orbits Earth in a nearly circular path at an angle of 51.6 degrees to the equator. This path was chosen so that Russian spacecraft could reach it without flying over China. The ISS travels at about 28,000 kilometers per hour and completes a full orbit around Earth every 93 minutes.

Because of the thin air in space, the ISS slowly loses altitude. To keep it in the right place, it sometimes fires its engines to boost itself higher. The ISS orbits between 370 and 460 kilometers above Earth. Space debris, like old rocket parts and tiny pieces of material, can be dangerous to the ISS, but it has special shields to protect itself. The ISS can be seen from the ground as a bright moving dot in the night sky, especially around dawn or dusk. Websites and apps can help people know when and where to look to see the ISS.

Environment, safety and crew health

The International Space Station (ISS) has special ways to keep astronauts safe and healthy in space. One big challenge is microgravity—a feeling of weightlessness because of the continuous freefall around Earth. This can be disturbed by things like air movement, equipment vibrations, and small forces from the station’s movement.

The ISS is also protected from harmful space radiation by Earth’s magnetic field, but solar flares and cosmic rays can still be dangerous. Astronauts sometimes hide in safer parts of the station during big solar storms. Radiation can damage cells and increase cancer risk, so the station has shielding and special medicine to help protect the crew.

Astronauts face noise from machines and systems all the time, which can affect sleep and communication. Special noise control measures help keep sound levels manageable. Other risks include small fires or leaks of ammonia, a chemical used in the station’s cooling system. The station has exercise equipment to help astronauts stay strong and healthy, since living without gravity can weaken muscles and bones. Living and working in close quarters with people from different cultures and languages can also be stressful.

Life aboard

The International Space Station (ISS) has a living space larger than a six-bedroom house. It includes seven private sleeping areas, three bathrooms, two dining rooms, a gym, and a large window with a 360-degree view. Long-term crew members have private quarters in different parts of the station, each equipped with a sleeping bag, a lamp, and storage space. Visiting crew members sleep in tethered bags attached to walls to avoid bumping into equipment.

A typical day on the ISS starts at 06:00 with wake-up, followed by morning routines and a planning meeting with Mission Control. The crew works for about 10 hours on weekdays and 5 hours on Saturdays, with free time for hobbies, family calls, or looking at Earth through the windows. The station orbits Earth quickly, experiencing 16 sunrises and sunsets each day, so windows are covered during sleep times.

Food on the ISS is specially packed to stay fresh for long periods and to avoid making a mess in zero gravity. Meals are often seasoned more strongly because flavors are dulled in space. Fresh foods like fruits and vegetables arrive with resupply missions. The station has galleys with warmers and water dispensers, and crews sometimes eat together, especially on special occasions. Experiments have grown vegetables like lettuce and kale, which the crew can eat, helping to add variety and nutrients to their meals.

The ISS has toilets designed for use in space. Waste is collected and stored until it can be removed by cargo spacecraft. Instead of showers, astronauts clean themselves with wet wipes or a water jet and special soap.

End of mission

The International Space Station was initially planned for a 15-year mission but has been extended many times due to its success. The oldest parts of the ISS have been in space for over 25 years.

In 2009, the U.S. planned to stop using the ISS in 2016, but this date was pushed back several times. By 2022, laws had been passed to keep the ISS operating until at least 2030. In early 2026, there was a plan to keep using the ISS beyond 2030 if private companies could not provide enough space for NASA's needs.

Russia has said it plans to leave the ISS after 2025, but its parts will help keep the station in orbit until 2028. There have also been discussions about moving parts of the ISS to other stations or using them for new projects.

Cost

The International Space Station is one of the most expensive things ever built, costing about US$150 billion by 2010. This money came from many countries: NASA spent $58.7 billion, Russia spent $12 billion, Europe and Japan each spent $5 billion, and Canada spent $2 billion. It also cost a lot to send many space shuttle flights to build it.

In culture

The International Space Station (ISS) stands as a symbol of human teamwork and scientific achievement. It shows how countries can work together peacefully in space.

The ISS has appeared in many movies, books, and games. Some films, like The Day After Tomorrow and Gravity, show the station in exciting stories. In 2022, a movie called The Challenge (Doctor's House Call) was even filmed inside the real ISS, making it the first feature film shot in space by actors and a director working together up there. Books such as Seveneves by Neal Stephenson and Orbital by Samantha Harvey also feature the ISS in their stories.