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The International Gamma-Ray Astrophysics Laboratory

Integral is a international mission with all 14 member states of the European Space Agency (ESA) plus USA, Russia, Czech Republic and Poland.

The International Gamma-Ray Astrophysics Laboratory will gather the most energetic radiation that comes from space - gamma rays. The spacecraft is scheduled for launch in April 2002 and will hopefully help solve some of the biggest mysteries in astronomy.

Gamma rays are more powerful than X-rays used in medical examinations, but the Earth's atmosphere acts as a shield to protect us from it. This means that gamma rays from space can only be detected by satellites. Integral will be the most sensitive gamma-ray observatory ever launched. It will detect radiation from the most violent events far away and from processes that made the universe habitable.

Every three days Integral will orbit the Earth once and it will spend most of its time at the furthest parts of its orbit; higher than 40.000 km. That is well outside the Earth's radiation belts, and hence Integral won't have to battle background radiation effects.

What are we made of?

Today's science has found an exciting answer to this question: Most of the elements in our bodies, and in everything around us, come from dead stars! That leaves us with a new question; how can new elements be formed when a star dies? Integral will help to find out more about this element-making process.

A second, very important task of Integral, will be to study compact objects like neutron stars and black holes. That is possible because gamma rays appear after a supernova explosion. Perhaps it will find the existence of some even denser objects than black holes. At the moment most astronomers believe that giant black holes lurk in the centre of the Milky Way, as in the centre of other galaxies. Integral will find evidence of these exotic objects, and also allow detailed studies of their physical properties.

There are some even more strange phenomena on the gamma-sky: flashes of extremely powerful radiation that suddenly appear somewhere and disappear again after a short time. Observations in different wavelengths confirm that these bursts are the biggest observed explosions in the universe. Yet we haven't go a clue on what it might be that explodes out there? Will Integral solve this cosmic mystery?


When we watch the sky in a clear night, we can see about 3 000 stars, some light-years away, with the naked eye. With a big telescope we can see millions of galaxies that are even billions of light-years away. But there is much more out there that we don't see since visible light is a small part of the spectrum of electromagnetic radiation. (as seen on the first page)

Most of the huge range of light rays arriving from the Universe is invisible to the human eye, and a large amount is blocked by the Earth's atmosphere. Therefore astronomers have learned how to look at these invisible rays. With big radio telescopes on Earth and clever satellites in space our knowledge about the Universe has been dramatically extended. And there will be many more discoveries

With Integral we will gain new understanding of objects and processes that emit the most powerful electromagnetic radiation. The gamma-rays detected by Integral are a million times more energetic than visible light.

Integral links

the International Gamma-Ray Astrophysics Laboratory (Integral's official homepage)

Mission overview

28th July 2000
Emma Button
Sarah Amandusson