__NOTOC__ A cleaning event is a phenomenon whereby

dust Dust is made of particle size, fine particles of solid matter. On Earth, it generally consists of particles in the atmosphere that come from various sources such as soil lifted by wind (an aeolian processes, aeolian process), Types of volcan ...

is removed from

solar panel A solar panel is a device that converts sunlight into electricity by using photovoltaic (PV) cells. PV cells are made of materials that produce excited electrons when exposed to light. These electrons flow through a circuit and produce direct ...

s, in the context of exploration and science rovers on

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

, supposedly by the action of

wind Wind is the natural movement of atmosphere of Earth, air or other gases relative to a planetary surface, planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heatin ...

. The term is used on several

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

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. The nature of the cleaning events is not known, but the assumption is that wind blows the dust off the panels. Cleaning events were discovered in 2004 when, several times, power levels increased by 5% overnight, in contrast to the expectation they would decreasethe added power allowed the missions to continue beyond their expected lifetime. 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. The term started being used in 2004 as the Mars Exploration Rovers' (MER) solar panels started to benefit from these events. The rovers were expected to last about 90 sols (Martian days) on Mars, after which dust would cover their solar panels and reduce solar power to levels too low for the rovers to operate. However, power levels went back up due to the cleaning events caused by the winds in the Martian atmosphere. Periodic cleaning events have allowed the MERs to operate far longer than the planned 3 months. The '' Spirit'' rover finally ceased operation in early 2010, and the '' Opportunity'' rover remained active until mid 2018, more than 14 years after landing. Cleaning events can either be rapid, such as overnight, or over many days where solar power slowly goes up. 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 power output of ''Spirit'' solar arrays increased from 223 watt-hours per day on 31 March 2009 to 372 watt-hours per day on 29 April 2009. ''Spirit'' had experienced multiple cleaning events during its operation that aided in its mission extension. However, the lack of cleaning events was noted as a factor in its demise. Other factors that affect solar power output include the opacity of the Martian atmosphere and Martian seasonal changes; however, this does not account for the directly observable removal of dust from the upper surfaces of the rovers as shown in the images. The Materials Adherence Experiment had a glass plate that allowed the dust to be cleared off; the device protected a

Gallium arsenide Gallium arsenide (GaAs) is a III-V direct band gap semiconductor with a Zincblende (crystal structure), zinc blende crystal structure. Gallium arsenide is used in the manufacture of devices such as microwave frequency integrated circuits, monoli ...

photo-cell. It was part of the

Mars Pathfinder ''Mars Pathfinder'' was an American robotic spacecraft that landed a base station with a rover (space exploration), roving probe on Mars in 1997. It consisted of a Lander (spacecraft), lander, renamed the Carl Sagan Memorial Station, and a ligh ...

program in the 1990s. This allowed the rate at which dust accumulated to be measured.

Noted cleaning events

*In early 2014 cleaning events boosted power levels on the ''Opportunity'' (MER-B) rover by 70%. A particularly strong cleaning event occurred in March 2014 while the rover was at

Endeavour crater Endeavour is an impact crater located in the Meridiani Planum extraterrestrial plain within the Margaritifer Sinus quadrangle (MC-19) region of the planet Mars. Endeavour is about in diameter. Using ''Mars Reconnaissance Orbiter'' data, phy ...

References

External links

*
"PIA07492: Before and After a Cleaning Event on ''Spirit''", JPL/NASA
{{DEFAULTSORT:Cleaning event Mars Exploration Rover mission Solar power and space

Noted cleaning events

See also

References

External links