.. _muse-overview: ************* What is MUSE? ************* MUSE ==== **Multi-slit Solar Explorer (MUSE)** is a `NASA Medium-Class Explorers (MIDEX) `__ satellite. Managed by the Lockheed Martin Corporation Advanced Technology Center (LM ATC) and led by Principal Investigator (PI) Dr. Bart De Pontieu of the Lockheed Martin Solar & Astrophysics Laboratory (LMSAL). The MUSE Investigation builds on the success of IRIS but focuses on the Sun's corona instead of the chromosphere. MUSE's radically innovative instrumentation and state-of-the-art numerical modeling will provide a breakthrough in our understanding of the physical processes that heat the multi-million degree corona, accelerate the solar wind and drive solar activity (flares and CMEs) that impacts Earth. MUSE provides the unprecedented combination of simultaneous sub-arcsecond coronal spectroscopy (0.4") along 37 slits and imaging (0.33"), while increasing by 30 to 100x the areal coverage and cadence over previous or planned spectrographs, enabled by a more than 30x higher telemetry rate. The MUSE Investigation includes a vigorous numerical modeling component that leverages the IRIS heritage. The MUSE payload consists of two instruments: * The Multi-slit Spectrograph: collects line profiles in bright coronal lines (Fe IX 171 Å ,Fe XV 284 Å, Fe XIX 108 Å), covering a large temperature range (0.7-12 MK) at the highest angular (0.4") and temporal resolution (1s slit dwelling time) ever achieved. * The Context Imager: based on the successful Hi-C rocket, collects even higher resolution (0.33") images (Fe XII 195 Å and He II 304 Å) over a larger field-of-view, showing transition region and coronal morphology and motions. MUSE addresses all of NASA's Heliophysics Science Goals and enables advances in all Key Science Goals of the Solar and Space Physics Decadal Survey. MUSE will fill a crucial gap in the capabilities of the Heliophysics System Observatory and next generation instruments such as DKIST, EUVST, Parker Solar Probe and Solar Orbiter. The MUSE project benefits from extensive flight heritage from IRIS, SDO and Hinode, ensuring low cost/schedule risks. The spacecraft and imager are at TRL 6 or higher now. We also use significant IRIS/SDO heritage for mission operations and data processing.