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A '''cleaning event''' is a phenomenon whereby [[dust]] is removed from [[solar panel]]s, particularly ones on [[Mars]], by the action of [[wind]]. The term '''cleaning event''' is used on several [[NASA]] webpages; generally the term is used in reference to the fact that Martian winds have blown dust clear off the solar panels of probes on Mars increasing their energy output.<ref>{{Cite web |url=http://www.nasa.gov/mission_pages/mer/mer-20070314.html |title=NASA Mars Rover Churns Up Questions With Sulfur-Rich Soil |date=March 14, 2007 |publisher=NASA/JPL}}</ref>
A '''cleaning event''' is a phenomenon whereby [[dust]] is removed from [[solar panel]]s, particularly ones on [[Mars]], by the action of [[wind]]. The term '''cleaning event''' is used on several [[NASA]] webpages; generally the term is used in reference to the fact that Martian winds have blown dust clear off the solar panels of probes on Mars increasing their energy output.<ref>{{Cite web |url=http://www.nasa.gov/mission_pages/mer/mer-20070314.html |title=NASA Mars Rover Churns Up Questions With Sulfur-Rich Soil |date=March 14, 2007 |publisher=NASA/JPL}}</ref>


The term started being used in 2004 as the [[Mars Exploration Rovers]]' solar panels started to benefit from these events.{{cn|date=November 2011}} The rovers were expected to last about 90 [[Timekeeping on Mars|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 MER rovers to operate for several years, rather than the planned 3 months.{{cn|date=November 2011}}<!-- should have a citation for this claim. This is a strong claim to link causation for the long mission to a single natural series of events. Do we have a source? -->
The term started being used in 2004 as the [[Mars Exploration Rovers]]' solar panels started to benefit from these events.{{cn|date=November 2011}} The rovers were expected to last about 90 [[Timekeeping on Mars|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 MER rovers to operate far longer than the planned 3 months. While ''[[Spirit (rover)|Spirit]]]'' rover finally ceased operation in 2011, ''[[Opportunity (rover)|Opportunity]]]'' rover remain active as of 2014, more than 10 years after landing.


Cleaning events can either be [[Spirit rover#Dust whirlwinds|rapid]], such as overnight, or over many days where solar power slowly goes up.<ref>{{Cite web |url=http://www.marsdaily.com/reports/Cleaning_Event_Boosts_Power_On_Opportunity_999.html |title=Cleaning Event Boosts Power On Opportunity |date=August 02, 2006 |work=Mars Daily}}</ref> For example, the MER-A ''Spirit'' rover, on April 18, 2009 and April 28, 2009 the power output of the solar arrays were increased by cleaning events.<ref>{{cite web |url=http://marsrovers.jpl.nasa.gov/mission/status_spiritAll_2009.html#sol1879 |title=Another Reset and a Cleaning Event |publisher=NASA/JPL |date=2009-04-22 |accessdate=2009-04-25 }}</ref><ref name="Update20090429">{{cite web|url=http://marsrovers.jpl.nasa.gov/mission/status_spiritAll_2009.html#sol1886 |title=Well Behaved, Less Dusty, in Difficult Terrain |publisher=NASA/JPL |date=2009-04-29 |accessdate=2009-05-04}}</ref> The power output of ''Spirit's'' solar arrays increased from 223 watt hours per day on March 31, 2009 to 372 watt hours per day on April 29, 2009.<ref name="Update20090429"/>
Cleaning events can either be [[Spirit rover#Dust whirlwinds|rapid]], such as overnight, or over many days where solar power slowly goes up.<ref>{{Cite web |url=http://www.marsdaily.com/reports/Cleaning_Event_Boosts_Power_On_Opportunity_999.html |title=Cleaning Event Boosts Power On Opportunity |date=August 02, 2006 |work=Mars Daily}}</ref> For example, the MER-A ''Spirit'' rover, on April 18, 2009 and April 28, 2009 the power output of the solar arrays were increased by cleaning events.<ref>{{cite web |url=http://marsrovers.jpl.nasa.gov/mission/status_spiritAll_2009.html#sol1879 |title=Another Reset and a Cleaning Event |publisher=NASA/JPL |date=2009-04-22 |accessdate=2009-04-25 }}</ref><ref name="Update20090429">{{cite web|url=http://marsrovers.jpl.nasa.gov/mission/status_spiritAll_2009.html#sol1886 |title=Well Behaved, Less Dusty, in Difficult Terrain |publisher=NASA/JPL |date=2009-04-29 |accessdate=2009-05-04}}</ref> The power output of ''Spirit's'' solar arrays increased from 223 watt hours per day on March 31, 2009 to 372 watt hours per day on April 29, 2009.<ref name="Update20090429"/>

Revision as of 20:41, 22 February 2014

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. credit:NASA/JPL-Caltech/Cornell

A cleaning event is a phenomenon whereby dust is removed from solar panels, particularly ones on Mars, by the action of wind. The term cleaning event is used on several NASA webpages; generally the term is used in reference to the fact that Martian winds have blown dust clear off the solar panels of probes on Mars increasing their energy output.[1]

The term started being used in 2004 as the Mars Exploration Rovers' solar panels started to benefit from these events.[citation needed] 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 MER rovers to operate far longer than the planned 3 months. While Spirit] rover finally ceased operation in 2011, Opportunity] rover remain active as of 2014, more than 10 years after landing.

Cleaning events can either be rapid, such as overnight, or over many days where solar power slowly goes up.[2] For example, the MER-A Spirit rover, on April 18, 2009 and April 28, 2009 the power output of the solar arrays were increased by cleaning events.[3][4] The power output of Spirit's solar arrays increased from 223 watt hours per day on March 31, 2009 to 372 watt hours per day on April 29, 2009.[4]

Other factors that affect solar power output include the opacity of the Martian atmosphere and Martian seasonal changes.

See also

References

  1. ^ "NASA Mars Rover Churns Up Questions With Sulfur-Rich Soil". NASA/JPL. March 14, 2007.
  2. ^ "Cleaning Event Boosts Power On Opportunity". Mars Daily. August 02, 2006. {{cite web}}: Check date values in: |date= (help)
  3. ^ "Another Reset and a Cleaning Event". NASA/JPL. 2009-04-22. Retrieved 2009-04-25.
  4. ^ a b "Well Behaved, Less Dusty, in Difficult Terrain". NASA/JPL. 2009-04-29. Retrieved 2009-05-04.

Media related to Mars Exploration Rover at Wikimedia Commons

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