IS☉IS instrument locationIS☉IS hardware being prepared for its mission, EPI-Lo hardware shown in 2017
Integrated Science Investigation of the Sun or IS☉IS, is an instrument aboard the Parker Solar Probe, a space probe designed to study the Sun. IS☉IS is focused on measuring energetic particles from the Sun, including electrons, protons, and ions. The parent spacecraft was launched in early August 2018, and with multiple flybys of Venus will study the heliosphere of the Sun from less than 4 million kilometers or less than 9 solar radii.
IS☉IS consists of two detectors, EPI-Lo and EPI-Hi, corresponding to detection of relatively lower and higher energy particles. EPI-Lo is designed to detect from about 20 keV per nucleon up to 15 MeV (megaelectronvolts) total energy, and for electrons from about 25 keV up to 1000 keV. EPI-Hi is designed to measure charged particles from about 1– to 200 MeV per nucleon and electrons from about 0.5 to 6 MeV, according to a paper about the device.
The shortname includes a symbol for the Sun, a circle with a dot in it: ☉. NASA suggests pronouncing the name as /iːsɪs/ in English.
Operations
Labeled diagram of IS☉IS
By September 2018, IS☉IS had been turned on and first light data was returned.
1234McComas, D. J.; Christian, E. R.; Wiedenbeck, M. E.; McNutt, R. L.; Cummings, A. C.; Desai, M. I.; Giacalone, J.; Hill, M. E.; Mewaldt, R. E.; Krimigis, S. M.; Livi, S. A.; Mitchell, D. G.; Matthaeus, W. H.; Roelof, E. C.; Schwadron, N. A.; Stone, E. C.; von Rosenvinge, T. T. (January 2011). The Integrated Science Investigation of the Sun (ISIS): Energetic Particle Measurements for the Solar Probe Plus Mission(PDF). 32nd International Cosmic Ray Conference. Beijing, China. Archived(PDF) from the original on 28 September 2022.