The International Space Station (ISS) is turning a spry 25 years old in 2023 and has brought us an immeasurable amount of value in scientific experimentation and cross-country collaboration.

‍

Here are 25 facts about this technological marvel that you may not know!

‍

1.) Five space agencies – USA, Russia, Europe, Japan, and Canada – cooperated to build the ISS

‍
The modules that make up the ISS were manufactured in different countries and assembled in space. Russia supplied the first module, which launched into orbit in 1998. Regardless of where they were built, all of the remaining modules hopped a ride into space aboard NASA space shuttles.

‍

2.) The first ISS inhabitants arrived in 2000

‍
The first crew to inhabit the ISS arrived in November 2000 aboard Expedition 1, a Russian-built Soyuz spacecraft. They included mission commander Bill Shepherd, an American astronaut, and two Russian cosmonauts.

Although all three men had extensive space experience, only one, Sergei Krikalev, had lived in space before. He had spent an entire year living aboard the Soviet MIR space station.

‍

3.) The ISS took over 1,000 hours of spacewalking to assemble

‍
By the end of primary construction in 2011, the ISS consisted of more than 150 components and 14 pressurized modules. Astronauts had spent a combined total of more than 1,000 hours in spacewalks to connect all the pieces.

‍

Since then, the cooperating space agencies have added five more modules to the ISS and are planning additional modules in the future. Japan launched the latest module in July 2021.

‍

4.) The ISS cost is approaching $200 billion

‍
Governments and private businesses had invested a combined total of $150 billion in the ISS by 2010. These included $59 billion from the U.S., $12 billion from Russia, $5 billion from Japan, $5 billion from Europe, and $2 billion from Canada into the space station itself and the rest into ferrying astronauts and components to and from the ISS aboard a variety of spacecraft.

‍

The U.S. spends an average of $3-$4 billion annually to staff and maintain the ISS.

‍

5.) The ISS required multiple space flights to complete

‍
Completing construction of the ISS took 136 different space flights involving seven different types of space vehicles to get all of the components into space.

‍

6.) The ISS is the third-brightest object in the sky

‍
Behind only the Moon and Venus, the ISS is the third-brightest object in the sky and can be seen by the naked eye. NASA provides a website called Spot the Station that lets you know when the ISS will travel over your location.

‍

7.) This thing is big

‍
The ISS is 356 feet long from end to end, about the length of a football field, and has a mass of 460 tons, or nearly a million pounds. The internal pressurized square footage is equal to that of a Boeing 747.

‍

8.) The ISS orbits the entire Earth in 90 minutes

‍
The ISS moves around Earth at 5 miles per second, completing 16 orbits of the Earth every 24 hours. As a result, crews see the sun rise and set 16 times daily!

‍

9.) ISS orbits from a height of about 250 miles

‍
The ISS's Apogee altitude (orbiting height) is 408 kilometers or about 250 miles. It takes about four hours from launch for a spaceship to reach the ISS.

‍

10.) Twenty countries have sent people to the ISS

‍
As of October 2022, 263 people from 20 countries have been aboard the ISS. Of those, 161 have been from the U.S.

‍

11.) A rotating, international crew of 7 operates the ISS

‍
As of October 2022, the ISS is hosting its 68th expedition crew, consisting of 5 men and two women from the U.S., Russia, and Japan. Onboard software includes over 350,000 sensors to ensure the health and safety of the crew.

‍

12.) See Earth from the ISS as the astronauts do

‍
Want to see Earth from the ISS? NASA provides a live stream on the web 24 hours a day.

‍

13.) ISS research focuses on improving our ability to live in space

‍
What do astronauts on the ISS do all day? They conduct scientific experiments. They use an instrument called NICER to study neutron stars, the densest objects in the universe. But most experiments involve learning how to live in space, including growing plants in microgravity, testing the survival rates of various microbes, and studying how time in space affects human DNA. They are also conducting experiments (currently using animals only) to determine whether normal human reproduction is possible in space.

‍

14.) The ISS living and working spaces combined are about the size of a large 6-bedroom house

‍
The ISS contains about the same living and working space as a 6-bedroom house on Earth, at 5,600 square feet. With six sleeping quarters, two bathrooms, a gym, a 360-view bay window, laboratories, and storage.

‍

15.) Astronauts breathe by splitting water – literally

‍
Onboard the ISS, water is split by electrolysis into oxygen and hydrogen to create breathable air for the cabin. The oxygen circulates on board, and the hydrogen is released into space.

‍

16.) ISS crews maintain a rigorous daily exercise routine

‍
Due to the near-absence of gravity, living in space is not healthy for humans. To counteract this, crews aboard the ISS undergo intense workouts lasting two and a half hours each day. They use three specially designed exercise machines, including a bicycle, a treadmill, and a weightlifting machine called the ARED.

‍

17.) All fluids consumed on the ISS are recycled

‍
Yes, the rumors are true. All urine produced by the crew and lab animals on board the ISS is cleaned, filtered, tested, and recycled back into the onboard water supply for future consumption – and the cycle repeats.

‍

However, American and Russian crew members maintain separate water supplies because they use different substances to control bacteria. While the Americans use iodine, the Russians use silver.

‍

18.) The ISS is a litterbug, but re-entry takes care of it

‍
Most garbage and solid waste created aboard the ISS is released into space. However, this space trash burns up automatically on re-entry into the Earth's atmosphere.

‍

19.) Astronauts have access to lots of entertainment options during downtime

‍
The ISS contains 52 different computers for different purposes. Some of those are to provide crew members with internet access for entertainment and communicating with the folks back home.

‍

20.) ISS inhabitants eat while floating in the air

‍
Those aboard the space station eat canned and rehydrated foods for their three meals daily while floating around instead of sitting. Mealtime takes longer than when on Earth because they have to be eaten slowly, one food item at a time, to ensure none gets loose and goes floating around (floating food can get into equipment and onboard experiments).

‍

21.) Onboard haircuts are equally tricky

‍
The ISS is a floating barbershop. Astronauts use special clippers attached to a vacuum. This is necessary to collect every hair particle so it can’t float around and clog air filters.

‍

22.) ISS crews sleep along the walls

‍
Due to the lack of gravity, crews aboard the ISS can’t lie in bed the way we do here on Earth. Instead, they crawl into sleeping bags attached to cabin walls. These bags, or compartments, are just large enough for one person to fit inside.

‍

23.) Clothing changes aboard the ISS give new meaning to “laundry service”

‍
Astronauts don’t do laundry. When clothes get dirty, they are burned. New clothing is shipped to the ISS periodically aboard crewless spacecraft.

‍

24.) The record for consecutive time aboard the ISS is 340 days

‍
American astronaut Scott Kelly and Russian cosmonaut Mikhael Kornienkowere spent 340 consecutive days aboard the ISS from March 2015 to March 2016. Their most intense experiment required no work, as it involved the study of the effects of being in space.

‍

Kelly has an identical twin, Mark, who is also an astronaut. Mark remained on Earth and served as an additional "control" against which changes in Scott's body over the 340 days were compared.

‍

25.) The ISS will come tumbling down in 2031

‍
In January 2022, NASA announced that it would de-orbit the ISS in January 2031 and intentionally crash it into the South Pacific Ocean.

‍

Many of the older modules on the ISS are seriously outdated due to technological advancements since they were created. Although the ISS could remain in orbit for much longer than 2031, the entire ship would eventually become useless, one module at a time.

‍

Final Thoughts: The Flagship of the Space Collaboration Era

‍

The ISS marked a stark and positive evolution from the Cold War-era space race in the decades prior. Previously warring countries like the USA, Russia, Japan, and Germany found themselves sitting at the forefront of space exploration at the turn of the decade; and the ISS was a sort of round table laboratory.

‍

As humanity’s largest space outpost, the ISS has gifted us insights into everything from astrophysics and materials to human physiology and psychology, bringing us dozens of solutions for global challenges in healthcare, the environment, energy, and digitalization.

‍

It also paved the way for further missions to the Moon and Mars– as well as a growing industry of space tourism and recreation.