Glossary

ESA (European Space Agency)
17 European countries work together as part of ESA on space projects. For example, they design and build satellites and send astronauts into space and are taking part in the Ariane-5 rocket programme.

EVA (Extra-Vehicular Activity)
When astronauts go outside the space station to carry out work, this is called an EVA.

ISS (International Space Station)
The ISS is a large structure floating in space 400 kilometres above the Earth. The astronauts use the ISS as a science laboratory.

Glossary

Astronaut = pilot or passenger (crew) of a spacecraft Astronauts are currently living and working on board the ISS.

Experiment = practical test to study and try to understand a phenomenon.
To study the effect of light on plants, scientists carry out experiments.

Gravity = the natural attraction that exists between two bodies of mass. The greater the mass, the greater the gravity.

Laboratory = a place designed and equipped to carry out scientific experiments.
The ISS is a laboratory in which astronauts do experiments under conditions of weightlessness.

Orbit = the path of an object moving around another body in space.
The Moon and satellites are in orbit around the Earth.

Planet = a large solid body which orbits around a star.
In the solar system, the Earth and eight other planets orbit around the Sun.

Radio communication = communication between two people using instruments able to transmit and receive radio waves through space. These radio waves can carry the sound of a voice from one point to another. Radio waves are like waves in the sea, which convey water from the sea to the coast.

Rocket = vehicle that carries astronauts and/or satellites from Earth into space.
The European rocket, Ariane-5, is launched from Kourou in French Guiana.

Satellite = an object orbiting around a larger object. Many artificial satellites have been sent by human beings to orbit around the Earth. They include Earth observation and telecommunication satellites.

Space = area in which the stars, planets and galaxies and other celestial bodies move. It is infinite and contains all the objects in the Universe.

Spacesuit = a suit worn by astronauts when they leave their spacecraft to do a spacewalk. It enables them to carry oxygen and provides protection from extreme temperatures and the Sun's rays.

Weight = a measure of the force which the Earth's pull exerts on a body. Because an elephant has a larger mass than a human, it is subject to greater attraction and therefore weighs more.

Weightlessness = the absence of gravity.
Astronauts in space live in a state of weightlessness.

If you would like us to add other words to this glossary, email us at ISSeducationteam@esa.int