The Interstellar Probe Mission was an interstellar precursor mission, proposed in 2000 by R. A. Wewaldt and P. C. Liewer of Caltech and JPL (Jet Propulsion Laboratory). This spacecraft would travel to a distance of 200–400 astronomical units (AU), using a solar sail propulsion system, to explore the boundary between the Solar System and interstellar space and to sample the interstellar medium. The Interstellar Probe would surpass 200 AU in 15 years, achieving about five times the exit velocity of the Voyager probes. After jettisoning its sail, the spacecraft would coast to 200–400 AU, exploring the Kuiper Belt, the boundaries of the heliosphere, and the local interstellar medium.