The National Aeronautics and Space Administration (NASA) and the Piano Spaziale Nazionale of the Consiglio Nazionale Delle Ricerche of Italy (PNS/CNR) are inviting researchers to participate in the first three flights of the Tethered Satellite System (TSS) on the space shuttle. The Tethered Satellite, a joint Italian/U.S. project, will deploy experiments in space at a distance of up to 100 km from the shuttle orbiter. Science instruments will remain tethered either upward or downward from the vechicle for approximately 16 hours at a time before being “reeled” back in. The first three missions, scheduled between 1987 and 1990, will conduct experiments primarily in the areas of space plasma, atmospheric, geomagnetic, and earth gravity physics.