[2][3] MIDAS is an atomic force microscope (AFM) designed to collect dust particles emitted from the comet,[4][5] and then scan them with a very sharp needle-like tip to determine their 3D structure, size and texture with very high resolution (4 nanometers).
[6] Some interplanetary dust particles collected in the Earth's stratosphere have been shown to have a cometary origin, but their precise provenance is typically unknown.
[6] MIDAS is mounted on the nadir panel of the Rosetta spacecraft and is composed of three main subsystems and an electronics box:[2][3][6] Dust collection is performed when close to the comet by opening the shutter and placing one of 61 targets directly behind the funnel.
[6] The MIDAS targets, on which dust particles are collected, are made of silicon and are rectangular in shape, with a dimension of 1.4 × 2.4 mm.
This is achieved by a coarse approach stage driven by a brushed DC motor encased in a pressurised vacuum bellows.
This motor drives a spindle which in turn raises or lowers a wheel placed in a spring-loaded wedge, as shown in the diagram.[which?]
Scientific data should be available to the public when the mission starts its primary science phase in November 2014, subject to the usual 6 months proprietary period.