OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) will be the main scientific imaging system on the orbiter of ESA's Rosetta mission to comet P/Wirtanen. The mission will be launched in January 2003 on an Ariane 5 launcher from Kourou in French Guyana. The OSIRIS instrument will be built by a consortium led by the Max-Planck-Institut für Aeronomie.