The International Space Station
The International Space Station (ISS) is an artificial satellite in a low Earth orbit, roughly 400 km above the Earth's surface. It was launched in 1998 from the Kennedy Space Center at NASA. The ISS is a collaboration between space agencies around the world, and is divided into two sections: the Russian Orbital Segment and the United States Orbital Segment.
Six astronauts live on board the ISS. They study:
Objects in orbit around the Earth are in freefall, and so they feel weightless. This is very useful to study the effects of gravity on plant and animal life. Inside the ISS, there are laboratories, control stations, and living quarters, connected to each other by 'nodes'. Solar arrays stretch out from the sides of the space station, collecting energy from the Sun to provide electrical power.
Astronauts exit the ISS through airlocks to perform spacewalks or repairs. Robotic arms assist the astronauts on their spacewalks, and move scientific equipment around the exterior of the space station. Docking ports allow other spacecraft to connect to the ISS, to bring other visiting astronauts or supplies. Astronauts fly to the ISS on the Russian Soyuz rockets.
The space station can be seen in the night sky without the aid of a telescope (with the 'naked eye'). It is a small, bright dot moving quickly past the stars. Track the ISS through the sky with Spot the Station.