The Structural/Thermal Test Model (STM) of ESA's Integral gamma-ray observatory was tested at ESTEC during June-September 1998. Following the thermal-vacuum testing in the Large Space Simulator (LSS), the STM underwent mass property measurements in the Multi-shaker area, and was then moved into the Large European Acoustic Facility (LEAF; seen here). Integral is planned for launch in 2001 to perform fine imaging and spectroscopy of 15 keV to 10 MeV celestial gamma-ray sources. [Image Date: 1998/09] [98.09.003-007]