NASA - National Aeronautics and Space Administration

When finished, the space station will be one of the brightest objects in the sky. Image Credit: NASA

The International Space Station is a large spacecraft in orbit around Earth. It serves as a home where crews of astronauts live. The space station is also a unique science laboratory. Several nations worked together to build and use the space station. The space station is made of parts that were assembled in space by astronauts. It orbits Earth at an average altitude of 220 miles. It travels at 17,500 mph. This means it orbits Earth every 90 minutes. NASA is using the space station to learn more about living and working in space. These lessons will make it possible to explore the moon, Mars and beyond.

How Old Is the Space Station?

The first piece of the International Space Station was launched in November 1998. A Russian rocket launched the Zarya (ZAR ee uh) control module. About two weeks later, the space shuttle Endeavour met Zarya in orbit. The space shuttle was carrying the

Module: a self-contained unit of a spacecraft

Unity node. The crew attached the Unity node to Zarya.

More pieces were added over the next two years before the station was ready for people to live there. The first crew arrived in October 2000. People have lived on the space station ever since. More pieces have continued to be added over time. NASA plans to complete construction of the space station by the time the space shuttle is scheduled to stop flying in 2010.

Pictured here are members of the 17th crew to live aboard the space station. Image Credit: NASA

How Big Is the Space Station?

When the space station is completed, it will have the volume of a five-bedroom house or two Boeing 747 jetliners. It will be able to support a crew of six people, plus visitors. On Earth, the finished space station would weigh almost a million pounds. Measured from the edges of its solar arrays, the station will cover the area of a football field including the end zones. It includes laboratory modules from the United States, Russia, Japan and Europe.

What Are the Parts of the Space Station?

In addition to the laboratories where astronauts conduct science research, the space station has many other parts. The first Russian modules included basic systems needed for the space station to function. They also provided living areas for crew members. Modules called "nodes" connect the other parts of the station.

Stretching out to the sides of the space station are the solar arrays. These arrays collect energy from the sun to provide electrical power. The arrays are connected to the station with a long truss. On the truss are radiators that control the space station's

Truss: a beam that serves as the space station's backbone to which some parts are connected

temperature.

Robotic arms are mounted outside the space station. The completed station will have four robot arms. Some will be used to help build the space station. Those arms can also move astronauts around when they go on spacewalks outside. Other arms will operate science experiments.

Airlock: an airtight room with two entrances that allows an astronaut to go on a spacewalk without letting the air out of the spacecraft

Astronauts can go on spacewalks through airlocks that open to the outside. Docking ports allow other spacecraft to connect to the space station. New crews and visitors arrive through the ports. Astronauts fly to the space station on the space shuttle or on a Russian Soyuz. Robotic spacecraft use the docking ports to deliver supplies.

Why Is the Space Station Important?

Microgravity: the condition of being weightless, or of the near absence of gravity

The space station has made it possible for people to have an ongoing presence in space. Human beings have been living in space every day since the first crew arrived. The space station’s laboratories allow crew members to do research that could not be done anywhere else. This scientific research benefits people on Earth. Space research is even used in everyday life. The results are products called "spinoffs." Scientists also study what happens to the body when people live in microgravity for a long time. NASA and its partners have learned how to keep a spacecraft working well. All of these lessons will be important for future space exploration.

Astronauts work in spacesuits to help build the space station. Image Credit: NASA

NASA is currently working on a plan to explore other worlds. One of the first steps is finishing the space station. One of the next will be to return to the moon. Astronauts will build an outpost there. NASA will use lessons it learns on the space station to build that outpost.


More About the Space Station:
International Space Station
Exploration
Interactive Space Station Reference Guide
International Space Station Assembly Sequence (Real)   →
International Space Station Assembly Sequence (Windows)   →
Where Is the Space Station Now?   →
International Space Station: International Partners
When Will New Parts Be Added to the Space Station?


David Hitt/NASA Educational Technology Services