Aspera

Aspera will map faint far-ultraviolet emission from the circumgalactic medium - the diffuse gas surrounding nearby galaxies - to investigate how galaxies accumulate and retain mass. Led by the University of Arizona under NASA's Astrophysics Pioneers Program, it is the first NASA astrophysics mission dedicated to mapping the O VI doublet near 103 nm, which traces the warm-hot gas thought to govern how galaxies build up over time.