1. Introduction - Geowissenschaften/EXCISS GitHub Wiki
The acronym EXCISS stands for Experimental Chondrule Formation at the International Space Station (ISS). As the name implies the experiment deals with the formation mechanism of chondrules, one of the oldest materials of our solar system. Chondrules are usually submillimeter to millimetre sized spherical objects which can be found in most types of meteorites and can make up to 80 vol.% of their mass in cases of primitive meteorite classes. Chondrules consist mostly of silicates, mesostasis (gap filling, mostly amorphous Ca, Al-silicate mix) and metal. They are meant to be the main building blocks of our solar system. This indicates that most of the planets and asteroids originally were made up of chondrules and their thermo-chemically altered products. Therefore, if we understand how chondrules are formed, we can gain substantial information about processes in the very early stage of our solar system.
It is commonly accepted that chondrules are formed within the first 10 million years of the existence of our solar system, which consisted of a protosun and a dense nebula of gases and silicate/metal dust particles, called Solar Nebula. The texture of chondrules indicates that they crystallized from a melt. The process(es), which melted the dust aggregates is still enigmatic and many conflicting theories for the formation of chondrules have been proposed, e. g. the nebular lightning theory. This theory assumes that electrical discharges led to the melting of dust aggregates which formed chondrules.
Since the question of chondrule formation is omnipresent in meteoritical science, the idea to develop a microgravity experiment about the formation mechanism of this important solids was obvious. The idea was to perform a straightforward experiment which will present crucial new data to the origin of our solar system and the first solids formed. In the EXCISS experiment, forsterite (Mg2SiO4) dust particles will be levitating between two electrodes in microgravity and be exposed to 100 electrical discharges over a time span of five days. The dust particles have a mean size of roughly 100µm. The experimental setup is described in the following sections