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) started as an idea for a space home. Scientists from many countries could work together there. Five space agencies joined this project: NASA from the United States, Roscosmos from Russia, ESA from Europe, JAXA from Japan, and CSA from Canada. They wanted to build the first space station together. It became the biggest human spacecraft ever made.

Purpose

The International Space Station (ISS) was built to be a research lab, an observatory, and a factory in low Earth orbit. It also helps us get ready for future trips to the Moon, Mars, and asteroids. Over time, the ISS has also been used for business, international teamwork, and teaching.

The ISS is a place for scientific research. It has power, data, and support for crew members to do experiments. These experiments study many things, like astrobiology, astronomy, physical sciences, and human health. One famous experiment is the Alpha Magnetic Spectrometer, which looks for dark matter. The space environment can be tough, but the ISS helps scientists learn how space affects living things and people. This research is important for future long trips into space.

International co-operation

The International Space Station is a very big space project. Five space agencies and fifteen countries work together on it. It started with an agreement in 1998. This agreement set the rules for everyone to follow.

Many other agreements came after to help with different parts of the work. Everyone needs to follow the same rules when they visit the space station.

Brazil was asked to join too. But Brazil had money problems and decided not to join in 2007. When 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 by many countries working together. Parts were made in places like Moscow and Huntsville, Alabama. These parts were carefully joined in space.

Building the station began in November 1998. Two first parts, called Zarya and Unity, were connected. Over time, more rooms and tools were added by astronauts during spacewalks and with robotic arms. Even when there were delays, the station kept growing. Now it has many modules from different countries, creating a large home for astronauts to live and work in space.

Structure

The International Space Station (ISS) is built so that pieces, called modules, can be added or taken away. This makes the station flexible and easy to change.

Pressurised modules

The ISS has several main parts 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 main part of the Russian section, launched in 2000. It is used for living and controlling the station.
• Destiny: The U.S. laboratory for science experiments, launched in 2001.
• Quest Joint Airlock: Lets astronauts do spacewalks.
• Poisk: A smaller airlock and place for Russian spacecraft to dock.
• Harmony: Connects the U.S., European, and Japanese parts.
• Tranquility: Holds life-support systems and exercise tools.
• Columbus: The science lab from the European Space Agency.
• Kibō: Japan’s research module.
• Cupola: An observation area with big windows.
• Rassvet: Used for storage and docking.
• Leonardo: Gives space for storing supplies.

Unpressurised elements

The ISS also has outside parts that are not pressurised:

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

Former module

• Pirs: The Russian airlock, taken away in 2021 to make room for new modules.

Planned components

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

Cancelled components

Some planned modules were cancelled due to money or redesign reasons, like 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 helps with many of these systems, with extra help from the US modules. The Nauka laboratory also has its own life-support systems.

The ISS makes its own oxygen using special devices. It removes carbon dioxide and other gases with filters. The station gets power from large solar panels that stretch out like wings. These panels turn to follow the Sun, making the most of sunlight. The solar panels power the station and its experiments. 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 crew on the International Space Station (ISS) gets an expedition number. These expeditions last up to six months, from launch until the crew leaves the station. At first, crews had three members. After the Space Shuttle Columbia accident, crews were reduced to two to keep the station running. When the Shuttle flew again, crew sizes grew. By around 2010, crews had six members. With larger commercial spacecraft starting in 2020, the crew size grew to seven.

Oleg Kononenko spent the most time in space at the ISS, with 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 missions 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. 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. Things like air movement, equipment vibrations, and small forces from the station’s movement can disturb this.

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

Astronauts hear noise from machines and systems all the time, which can affect sleep and talking. Special noise control measures help keep sound levels down. 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 closely with people from different cultures and languages can also be challenging.

Life aboard

The International Space Station (ISS) has a living space larger than a six-bedroom house. It has 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 rooms in different parts of the station. Each has a sleeping bag, a lamp, and storage space. Visiting crew members sleep in bags attached to walls to avoid bumping into equipment.

A typical day on the ISS starts at 06:00 with wake-up. Then there is a morning routine and a planning meeting with Mission Control. The crew works for about 10 hours on weekdays and 5 hours on Saturdays. They have free time for hobbies, family calls, or looking at Earth through the windows. The station moves very fast around Earth, seeing 16 sunrises and sunsets each day, so windows are covered during sleep times.

Food on the ISS is 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 made 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 meant to work for 15 years, but it has been used much longer because it has been very successful. Some parts of the ISS have been in space for over 25 years.

In 2009, the U.S. thought it would stop using the ISS in 2016, but this date was changed many times. By 2022, laws were made to keep the ISS working until at least 2030. In early 2026, there was a plan to keep using the ISS after 2030 if private companies could not give NASA enough space.

Russia has said it plans to leave the ISS after 2025, but its parts will help keep the station moving until 2028. There have also been talks 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. It cost about US$150 billion by 2010. The money came from many countries. NASA spent $58.7 billion. Russia spent $12 billion. Europe and Japan each spent $5 billion. 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) shows how countries can work together 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 filmed inside the real ISS. Books such as Seveneves by Neal Stephenson and Orbital by Samantha Harvey also feature the ISS.