INTEGRAL - EXPLORING THE GAMMA-RAY FRONTIER

The International Gamma-Ray Astrophysics Laboratory (INTEGRAL) is conc eived as the next logical step in Gamma-Ray astronomy, after the U.S. Compton Gamma-Ray Observatory (CGRO) and the Russian/European GRANAT m ission. Through the use of new technology, INTEGRAL will considerably be more powerful than these earlier missions, It will provide a combin ation of high sensitivity and high energy resolution (about 30 times b etter than CGRO) and high angular resolution (about 15 times better th an CGRO) that has not been achieved in any prior mission. The mission is planned in co-operation between Europe, the U.S. and Russia. The sp acecraft could make use of a common bus with XMM (X-Ray Multi Mirror), now under development at ESA. Two options are envisaged for the launc h : ARIANE 5 or the Russian Proton. An international team of scientist s and engineers has recently completed a phase A study, which demonstr ates the scientific merit and the feasibility of the mission as it is defined. This paper presents the main requirements for the INTEGRAL mi ssion and for the common bus, and it shows how it is satisfied with th e proposed design from an engineering viewpoint. The programmatic aspe cts are also briefly addressed.