International Space Station: Preparing Humans for Deep Space Exploration

Facts Worth Sharing

  • The International Space Station (ISS) is a permanently crewed, multinational space laboratory in low-Earth orbit.
  • NASA and its international partners conduct research aboard the ISS that helps us prepare for human deep space exploration missions.
  • The ISS is the easiest artificial object to see in the night sky. Use NASA's Spot the Station to find out when it will fly over your location.

Why do we need the International Space Station?

As humans prepare to explore the Moon and Mars, we must understand how astronauts will cope with spaceflight side effects like vision degradation, bone loss, and social isolation. We must also thoroughly test technologies that will be needed to keep humans alive in deep space, where supply ships and quick returns to Earth are not available.

The International Space Station, or ISS, is a permanently crewed space lab in Earth orbit. Continuously staffed since 2 November 2000, it is the longest-running space station program of all time. NASA and its international partners conduct research aboard the ISS that helps us prepare for deep space.

The ISS shows that multiple countries and private companies can work
together for the peaceful exploration of space. Born out of the ashes of
the Cold War as a way for the U.S. and Russia to focus on a common
goal, the station has largely remained unaffected by Earthly politics. It operates thanks to the cooperation of 15 nations working under formal international agreements.

As one of the world’s longest-running spaceflight programs, the ISS holds a special place in popular culture. In the United States, a majority of the public believes astronauts, not just robots, should explore space. Astronauts on the station regularly speak with school children, inspiring new generations of scientists, technologists, engineers, artists, and mathematicians. The station’s societal impact combined with its function as a one-of-a-kind research laboratory enables it to directly and indirectly benefit space science and exploration.

Cosmonaut Mikhail Kornienko
Cosmonaut Mikhail Kornienko Roscosmos cosmonaut Mikhail Kornienko waves through an ISS window during an August 10, 2015 spacewalk. Roscosmos

How the International Space Station works

The ISS core consists of modules launched by U.S. and Russian rockets over the course of 13 years. The station has a pressurized volume equivalent to a Boeing 747, with nearly half of that available for the crew.

Astronauts staff the station in pairs of 3 or 4-person crews assigned to overlapping 6-month missions, with each unique complement of up to 7 people composing a numbered Expedition (each crew serves on two Expeditions during their stay).

Science and research aboard the ISS generally falls into 4 categories:

  • Studies on how living in space affects the human body
  • Technology demonstrations for future human spaceflight equipment, including experience gained from current operational systems
  • Physical science experiments that benefit from the station’s weightless environment
  • Earth science and astrophysics instruments that use the station as an orbital platform

A fleet of international and commercial spacecraft service the ISS. Current crew vehicles are the Russian Soyuz and SpaceX Dragon. Current cargo vehicles are Soyuz, Dragon, and Northrop Grumman's Cygnus. Future vehicles include Boeing's Starliner for crews, and Japan's HTV-X and the Sierra Nevada Dream Chaser for cargo.

The final flyaround
The final flyaround The International Space Station (ISS) as seen from Space Shuttle Atlantis on 19 July 2011 during the shuttle program's final fly-around inspection. NASA

How you can support the International Space Station

Planetary Society co-founder Carl Sagan once said that when you’re in love, you want to tell the world. Space missions like the International Space Station are dependent upon sustained public enthusiasm from people like you. You know your audience best; we've got tools to help.

Tell the world

  • Spread the Facts Worth Sharing at the top of this article
  • Send this page to others using the short URL planetary.org/iss
  • Share pretty pictures of astronauts, the ISS, and the Earth
  • Use NASA's Spot the Station to see the ISS fly overhead, and encourage others to do the same

Learn more

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