In Situ Investigation of Charged Dust Particles Above the Lunar Surface at the Chang’E-5 Landing Site

The mysterious “lunar horizon glow” observed in the 1960s and 1970s was the first space observation possibly related to electrostatic dust transport; however, are there really large amounts of electrostatically transported dust particles in the lunar near-surface space? This is largely an open question at present. Here, we first report the in situ investigation results for the charged dust particles obtained by the charged dust detector onboard China’s Chang’E-5 (CE-5) mission. The results show that, within the detector’s detection limit, there are almost no charged dust particles with charge–mass ratios greater than ~0.24 to ~1.96 C/kg and velocities less than ~0.56 to ~0.07 m/s as the scanning voltage decreases from 80 to 10 mV at the location of ~2 m above the CE-5 landing site as the solar elevation angle elevated from ~41.8° to ~45.0°, under the framework of the dynamic fountain model. Additionally, the upper limit for the amounts of dust deposited on the detector during the exploration period of ~12 h is ~8.0 × 10 −2 μg/cm 2 .