International Gamma-Ray Astrophysics Laboratory

ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Spain, Switzerland), Czech Republic and Poland, and with the participation of Russia and the USA. SA

European Space Agency

• ESA Mission Manager:Arvind Parmar
• ESA Project Scientist:Christoph Winkler
• IBIS Principal Investigators: P. Ubertini (IAS/CNR Rome, Italy), F. Lebrun (CEA Saclay, France), G. Di Cocco (ITESRE Bologna, Italy).
• SPI Principal Investigators: J.-P. Roques, (CESR Toulouse, France), V. Schönfelder (MPE Garching, Germany).
• OMC Principal Investigators: M. Mas-Hesse (INTA/LAEFF Madrid, Spain).
• JEM-X Principal Investigator: N. Lund (DSRI Copenhagen, Denmark).

6 years

Integral's task will be to gather the most energetic radiation in the Universe, giving insight into the most violent processes in the Universe. Gamma-rays are even more powerful than X-rays (used in medical examinations). However, they are blocked by the Earth's atmosphere so gamma-ray astronomy must be largely space-based. Integral's varied observation programme includes studying:

• How black holes interact with their surroundings
• The explosion of supernovae and their role in forming chemical elements
• The nature of the powerful gamma-ray bursts
• Transient sources that suddenly change their brightness
• Making the most sensitive map of the distribution of gamma-ray sources in our Galaxy

Design: Integral consists of two main sections: the service module and the payload module. The payload module contains the four scientific instruments and is joined to the service module, which houses essentials such as power distribution, communications and satellite control. To keep costs down, the service module design is the same as that used in XMM-Newton. The whole spacecraft is three-axis stabilised, allowing it to be pointed with a high degree of accuracy at its targeted celestial objects.

Dimensions: 5x3.7x3.7 metres. The deployed solar panels are 16 metres across.

Mass: 4 tonnes at launch, including 2 tonnes of payload.

Industrial involvement: The prime contractor is Alenia Spazio leading an industrial consortium involving 26 companies from 12 European countries and one company in the United States. Approximately 1400 people were involved in the production of Integral, including the scientists and engineers responsible for the instruments, ground segment, and science data centre.

Imager on Board the Integral Satellite - IBIS

IBIS provides sharper gamma-ray images than any previous gamma-ray instrument. It can locate sources to a precision of 30 arcseconds, the equivalent of measuring a person standing in a crowd, 1.3 kilometres away.

Principal Investigators: P. Ubertini (IAS/CNR Rome, Italy), F. Lebrun (CEA Saclay, France), G. Di Cocco (ITESRE Bologna, Italy).

Spectrometer on Integral - SPI

SPI measures the energy of incoming gamma-rays with extraordinary accuracy. It is more sensitive to faint radiation than any previous gamma-ray instrument and allows the precise nature of gamma-ray sources to be determined.

Principal Investigators: J.-P. Roques, (CESR Toulouse, France), V. Schönfelder (MPE Garching, Germany).

Optical Monitoring Camera - OMC

OMC automatically takes an image of the sky at optical wavelengths whenever the gamma-ray telescopes are working. This allows astronomers to match the gamma-ray source with an optical counterpart, thus permitting further investigation with ground-based optical telescopes.

Principal Investigators: M. Mas-Hesse (INTA/LAEFF Madrid, Spain).

Joint European X-Ray Monitor - JEM-X

JEM-X performs a similar task to the OMC but at X-ray wavelengths. It provides X-ray images with similar positional accuracy as IBIS. These data allow astronomers to simultaneously study the behaviour of gamma-ray sources at X-ray wavelengths. Previously, such investigations have never been routinely possible.

Principal Investigator: N. Lund (DSRI Copenhagen, Denmark).

Integral was launched the 17th of October 2002, using a Russian Proton rocket from the Baikonour Cosmodrome in Kazakhstan. The Proton is Russia’s largest operational launch vehicle. It is more than 57 metres tall and its mass at liftoff is around 700 tonnes.

Integral was first placed in a low parking orbit around the Earth. About 50 minutes after launch, an attached upper stage rocket fired, putting Integral into a transfer orbit. The upper stage rocket then separated and Integral used its own manoeuvring rockets to reach its operational orbit after 72 hours. Its lowest point is 9,000 kilometres and its highest point is 153,000 kilometres. Such an elongated orbit is essential to keep Integral out of the Earth’s harmful radiation belts, which distort the view of the high-energy Universe.