The Io Volcano Observer (IVO)
Elizabeth P Turtle, Applied Physics Laboratory Johns Hopkins, Laurel, MD, United States, Alfred S McEwen, University of Arizona, Lunar and Planetary Laboratory, Tucson, United States and IVO Team
Contact First Author: Elizabeth P Turtle; Elizabeth.Turtle@jhuapl.edu
Previously Published Material: Abstract submitted for EGU
English Abstract:
IVO, first proposed as a NASA Discovery mission in 2010, uses advanced lightweight solar arrays and a 1-dimensional pivot to achieve observing flexibility during a series of fast (~18 km/s) flybys of Io. All science objectives from the Io Observer New Frontiers concept recommended in the 2011 Planetary Science Decadal Survey are addressed by IVO's five instruments plus gravity science: Narrow- and wide-angle cameras (NAC and WAC), dual fluxgate magnetometers (DMAG), a thermal mapper (TMAP), and particle environment package for Io (PEPI) consisting of an ion and neutral mass spectrometer (INMS) and a plasma ion analyzer (PIA). A student collaboration hotspot mapper (HOTMAP) is also an option. The NAC and TMAP are on a ±90° pivot for off-nadir targeting during encounters and for distant monitoring. WAC and HOTMAP are mounted on the S/C nadir deck, and observe during ±20 minutes of Io closest approach. PEPI is mounted on the S/C structure with the INMS field of view in the ram direction when the S/C nadir deck points at Io, and the PIA and has a large (hemispheric) field of view to include the upstream direction. The DMAG sensors are on the end and middle of 3.8-m boom and collect data continuously.
IVO launches in 2021, arriving at Jupiter in early 2026. Its highly elliptical orbit with perijove near Io is inclined >40° to Jupiter’s orbital plane, which provides opportunities to observe Io's poorly explored high latitudes and also minimizes total ionizing radiation dose compared to other Jupiter orbiters (<10% that of JUICE). Four of the encounters are designed for optimal measurement of induced magnetic signature from mantle melt. Two can be used for gravity science, pointing the high-gain antenna at Earth during the encounters. The final flyby includes a flythrough of Pele’s plume, if it is active, for gas composition. Encounter periods last ~1 week, including global monitoring and four Io eclipses, with distant monitoring and data playback near apojove. The apoapse period of each orbit provides extended monitoring of Io and Europa at high phase angles (>120°), best to detect and monitor volcanic plumes as well as high-temperature hot spots on Io. IVO will collect at least 20 Gb of science data per encounter: 100 times the Io data from the 8-year Galileo tour.
