IMAP-Hi consists of two identical, single-pixel high-energy energetic neutral atom (ENA) imagers mounted at fixed angles of 90 and 45 degrees relative to the spacecraft spin axis. These imagers measure neutral atoms entering our solar system from the outer edge of the heliosphere as they move towards the Sun. The ENA imagers collect the neutral atoms, sort them by type, and then map their incident direction from the outer heliosphere. IMAP-Hi uses a time-of-flight (TOF) section to identify hydrogen (H) and helium (He) and heavier atoms such as carbon (C), nitrogen (N), oxygen (O), and neon (Ne). With each spin of the spacecraft, the imagers sample swaths in the sky that include the ecliptic poles and four additional locations in the ecliptic plane. Some low latitude regions, that contain ENA emissions from the nose and tail of the heliosphere, as well as most of the IBEX Ribbon and Belt, are sampled twice within as little as 1.5 months which allows it to explore short ENA variability.
IMAP’Hi's design and assembly is led by Los Alamos National Laboratory (LANL) in collaboration with Southwest Research Institute (SwRI), University of New Hampshire (UNH), and University of Bern (UBe).