We present in-situ ion composition and velocity measurements from the Enhanced Polar Outflow Probe during the August 2017 solar eclipse, which crossed the path of totality at ~640 km altitude within 10 minutes of totality passing. These measurements reveal two distinct H+ ion populations, and show a ~40% decrease in topside plasma density, a similar drop in upward but not downward H+ ion flux, and a downward O+ ion velocity of ~100 m/s. These features are directly linked to changes in the H+/O+ composition and field-aligned or interhemispheric light ion flow, and reduction in the negative spacecraft potential. These observed features were absent on the preceding, non-eclipse days, and corroborate the reduction in F-region plasma density and topside Total Electron Content (TEC) observed by the Global Position System (GPS) receivers onboard. They are attributed to the temporary reduction of photoionization in the eclipsed F-region.