International Space Station (ISS)

The International Space Station (ISS) is the largest orbiting spacecraft ever built. The first crew members arrived at the ISS in 2000, and while most astronauts stay on board for six months or less, only a few have remained longer. At first glance, it may seem that the station is floating freely, unaffected by gravity, as everything aboard appears weightless. However, gravity also pulls on the ISS. The ISS is constantly falling toward Earth but moves forward at a very high speed of approximately five miles per second. This speed allows it to stay in orbit, as its trajectory matches the curvature of Earth's surface. Essentially, the ISS is falling around Earth, maintaining its orbit without ever hitting the ground. The ISS is a laboratory with an international crew of six people. Crew members conduct research in various fields, including space science, physical science and biological science. The station is powered by solar arrays, which make it the second brightest object in the night sky, after the Moon. ## Keywords ISS International Space Station satellites astronaut cosmos