The Earth orbit environment is an ideal place for the monitoring and collecting of meteoroids and space debris. The intact capture of these solid particles in space is of special interest in order to understand their natural vs artificial origins and to evaluate the risk for hypervelocity impacts on external structure of spacecrafts. Searching for these results the COMET-99 experiment flew onboard the MIR station between November 1998 and April 1999. During the experiment some silica-aerogel collectors were exposed to the space, capturing a conspicuous number of solid particles. The main part of my PhD work has been devoted to the extraction and laboratory analyses of some grains captured in the COMET-99 aerogel collectors. Moreover, I have explored new active and passive techniques for dust monitoring and collecting in Low Earth Orbit, projecting an experiment of new conception to be performed onboard the International Space Station.