The INTEGRAL spacecraft

The INTErnational Gamma Ray Astrophysics Laboratory (INTEGRAL) is being dev eloped by ESA as the second medium-size satellite of the long-term scientif ic plan Horizon 2000 It is an observatory providing an excellent opportunit y to the scientific community for detailed imaging and high-resolution spec troscopy of Gamma-ray sources. After completion of the design and development phase the Structural Thermal Model of the Integral Spacecraft and its four scientific instruments is pr esently being tested. First tests took place in spring 1998 at the ESTEC te st facilities. Late summer 1998 he Engineering Model test campaign will fol low. This paper summarises he key programmatic milestones of he project. highlig ht the final design characteristics of the satellite, report on the first t est results and describe the orbital scenario of he mission and the herewit h-related requirements to the satellite.