Nozomi (Japanese: のぞみ, lit. "Wish" or "Hope," and known before launch as Planet-B) was a Mars orbiter that failed to reach Mars due to electrical failures. The mission was terminated on December 31, 2003.It was constructed by the Institute of Space and Astronautical Science, University of Tokyo and launched on July 4, 1998, at 03:12 JST (July 3, 1998, at 18:12 UTC) with an on-orbit dry mass of 258 kg and 282 kg of propellant.Nozomi was designed to study the upper Martian atmosphere and its interaction with the solar wind and to develop technologies for use in future planetary missions. Specifically, instruments on the spacecraft were to measure the structure, composition and dynamics of the ionosphere, aeronomy effects of the solar wind, the escape of atmospheric constituents, the intrinsic magnetic field, the penetration of the solar-wind magnetic field, the structure of the magnetosphere, and dust in the upper atmosphere and in orbit around Mars. The mission would have also returned images of Mars' surface.