Cleaning event

A cleaning event is a phenomenon whereby dust is removed from solar panels, in the context of exploration and science rovers on Mars, supposedly by the action of wind.

The term is used on several NASA webpages; generally supposing that Martian winds have blown dust clear off the probes on Mars, including the solar panels which power them, increasing their energy output.

[2] One theory is that wind currents in craters aid in cleaning events, and also if the rover is sloped, this is speculated to help remove dust.

[3] For example, with the MER-A Spirit rover, on 18 and 28 April 2009, the power output of the solar arrays was increased by cleaning events.

The Materials Adherence Experiment had a glass plate that allowed the dust to be cleared off; the device protected a Gallium arsenide photo-cell.

Circular projection showing MER-A Spirit 's solar panels covered in dust in October 2007 on Mars. Cleaning events have periodically increased power from the solar arrays.
Overhead shot of Spirit without accumulated dust (November 2008)
Spirit 's sundial before and after a cleaning event
Time-lapse composite of the Martian horizon during Sols 1205 (0.94), 1220 (2.9), 1225 (4.1), 1233 (3.8), 1235 (4.7) shows how much sunlight the dust storms blocked; Tau of 4.7 indicates 99% blocked.