In Situ,Remote,and Laboratory Investigations of Mesospheric Aerosols/Dust and Their Role in Atmospheric Chemical and Physical Processes.

The project MAXIDUSTY-II (MXD-II) is centered on preparing a rocket payload specially designed to investigate ice and dust cloud particles in the Earth's middle atmosphere at heights above ca 80 km. MXD-II will contain up to 6 different ice and dust probes, some of totally new design, to improve our understanding of the physics and chemistry of the various particles. The payload will also contain several instruments for measuring basic plasma parameters like electron and ion density ad temperature. It will also contain several small daughter payloads which will be ejected below the cloud layers to give 3-dimenional measurements of some plasma parameters as they fly through the clouds on parallel orbits to the payload but with increasing distances from it. The payload MXD-II will map size, density and charges on the particles and investigate the chemistry of the ice particles. Solid particles, the so-called meteoric smoke particles (MSP) which are produced when meteorites burn up in the atmosphere will be collected and brought back for chemical analysis. This has never been successfully done before. A better knowledge of the structure and composition of the middle atmosphere ice and dust particles is important both because much of the chemistry in this layer occur on the surface of solid particles, and also because MSP will act as condensation sites for clouds not only in the middle atmosphere but also lower down in the stratosphere. We expect the results of MAXD-II to lead to an improved understanding of how the middle and upper atmosphere connect to and influence on the lower parts of the atmosphere.

The aim of the MAXIDUSTY-II project is to enhance our understanding of key physical and chemical processes in the Earths mesosphere and of its coupling to other atmospheric regions. The investigations will involve the launch of a rocket payload MAXIDUSTY- II which will include several recently developed dust and plasma probes and a new dust probe, MESS. Using a new sampling technique, MESS will collect and return meteoric smoke particles for the first time. The launch will be supported by the EISCAT radar s and Heating Facility and the UiT MORRO 56 MHz radar , by all relevant ground-based instrumentation at Andøya Rocket Range, and by satellite observations. The major goals of the investigations are to reveal the chemical content of the mesospheric cloud (NLC/PMC) particles by in situ mass spectroscopy, weigh collision fragments from impacting ice particles, find the secondary charging effects, mass analyze the incoming primary dust particles, and analyze smoke particles brought back by the MESS pro be. This, combined with the other rocket, satellite, and ground-based observations, together with theoretical modeling and laboratory experimental results, will lead to an improved understanding of smoke and PMC particle formation and evolution, and of th e chemical and physical processes occurring in the mesosphere. The new knowledge that will emerge from the MAXIDUSTY-II project is expected to be important in validating and improving Whole Atmosphere Models, and satellite observation techniques, as wel l as laboratory experiments related to chemical processes in the upper atmosphere. In the MXD-II project we will also install and equip a large plasma vacuum tank for instrument testing to ensure the optimal performance of the payload probes. The payload will carry up to four small daughter payloads to be ejected in the mesosphere to conduct 3D measurements of vital parameters such as the plasma density and possibly the dust charge density.