National Space Development Agency of Japan (NASDA) successfully launched the Tropical Rainfall Measuring Mission (TRMM) observatory at 06:27 (JST) on Nov. 28, 1997. The TRMM satellite carries the first spaceborne Precipitation Radar (PR) which was developed by NASDA and Communications Research Laboratory. The PR can measure the horizontal and vertical structure of rain day and night, and over ocean and land. This capability allows scientists for the first time ever to grasp the three-dimensional structure of rain in the tropics and sub-tropics around the globe. In addition to the PR, the satellite carries four more sensors which were developed by National Astronautics and Space Administration (NASA): the TRMM Microwave Imager (TMI), the Visible Infrared Scanner (VIRS), and the Cloud and the Earth's Radiant Energy System (CERES), the Lightning Imaging Sensor (LIS). Preliminary results and images from these sensors are shown in this paper.