The Spectroscopy of Plasma Evolution from Astrophysical Radiation Mission

The Spectroscopy of Plasma Evolution from Astrophysical Radiation (or the Far-ultraviolet Imaging Spectrograph) instruments, flown aboard the STSAT-1 satellite mission, have provided the first largearea spectral mapping of the cosmic far ultraviolet (FUV, λ 900-1750) background. We observe diffuse radiation from hot (10 – 10 K) and ionized plasmas, molecular hydrogen, and dust scattered starlight. These data provide for the unprecedented detection and discovery of spectral emission from a variety of interstellar environments, including the general medium, molecular clouds, supernova remnants, and super-bubbles. We describe the mission and its data, present an overview of the diffuse FUV sky’s appearance and spectrum, and introduce the scientific findings detailed later in this volume. Subject headings: ultraviolet: ISM: general