Dust and ionospheric constituents measured in the MLT during noctilucent cloud conditions

The mesosphere – lower thermosphere (MLT) contains dust particles made of both ice and refractory materials. Since the MLT overlaps with the heights of meteor ablation, it contains small nanometric particles made of cosmic dust material known as meteor smoke. The smoke particles influence the charge balance and ion chemistry and may serve as condensation nuclei for the formation of the ice particles. The ice particles are observed in summer at mid and high latitudes near the mesopause as noctilucent clouds (NLC) or polar mesospheric clouds (PMC). The presence of ice particles in combination with charge interactions, neutral air turbulence and dynamics also leads to specific radar echoes, known as polar mesospheric summer echoes (PMSE). Radar observations of PMSE and PMC/NLC measurements with cameras or lidar are among the few long-term observations around the summer mesopause. PMC/NLC measurements with satellites, cameras or lidar and PMSE measurements with radar indicate there are changes over the last decades. Aside from the ice and the meteoric smoke, space debris is possibly a third source of dust in the MLT that increases over time.The Maxidusty-2 (MXD2) allowed to measure dust, ions and neutrals from a rocket launched from Andoya, Norway (69.1° N, 16° E) on 5 July 2025 around 8:01 am local time. The MXD2 science payload included four dust in-situ detectors, a neutral gas instrument as well as a Faraday rotation experiment and Langmuir probes to measure electron density. Two independent and different instruments collected dust particles. NLC were observed at that time with the Alomar RMR lidar close by. PMSE were observed at the same time with the MAARSY radar close to the launch site and with the EISCAT radar in Ramfjord (69.6° N, 19.2° E) near Tromsoe at about 130 km distance. All in situ instruments recorded science data. The recovery was successful, and analysis of the collected refractory dust samples is ongoing. An overview of the campaign measurements is given. The initial analysis notably shows that the dust instruments measured a signal at the altitude of the NLC but only small signals at the altitude of higher PMSE layer. We discuss the results in terms of dust charging and the link between dust and the other parameters measured.