ESA Document - Emits - ESA

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4.3.5.3 Mars environment description
Figure 4-49: Power inputs at MEV level
HMM
Assessment Study
Report: CDF-20(A)
February 2004
page 300 of 422
On Mars, there are specific degradation factors affecting solar energy technology performances
(typically solar cells):
• Presence of direct but also diffuse light from the atmosphere and suspended dust particles
(‘diffusion’)
• Scattering of the sunlight spectrum towards the red end, due to suspended dust particles
(‘scattering’)
• Dust deposition effects on solar array surfaces (‘dust deposition’)
Note that diffusion, scattering and dust deposition effects are not constant but vary depending on
seasonal and geographical conditions, as well as on the occurrence of large dust storms.
In summary, solar cell efficiencies can be broadly affected by the Martian climate changes, and
to an extent that can only partially be quantified for the time being.
Other important environmental factors are:
• Potentially lower operational temperatures than orbital conditions
• High-speed winds, but with much lower force than in similar circumstances on Earth, due
to the lower ambient pressure (average value is 6.4 mbar compared with Earth average
1013 mbar)
• The presence of oxidizing soil characteristics (and potential corrosion of PVAs).
For more information on the issues presented above can be found in [RD83] through [RD85].
The source of information for the Sun irradiance at Mars ground level is the Martian Climate
database ([RD83]), which provides accurate information relating to the Mars latitude/longitude