Does anyone here know anything about the ICON satellite? I have a few questions… : meteorology

I’ve been reading the documentation but I’m still unclear about a few things. For example, with the IVM instrument, at what altitude is it measuring ion temperatures and densities? From https://icon.ssl.berkeley.edu/Observatory/Instruments/IVM/IVM-How-it-works it kinda seems like it measures at the altitude of the spacecraft, since the instrument extracts data from the ions that actually strike the collector. Is that right? Or does it do some sort of spectroscopy that I’m not finding anywhere?