Dust

On Earth, dust is washed out of the air by rain, and is cemented together to form rocks, or deposited as mud. On Mars, this does not happen, and dust is blown about for long periods. Dust Storms distribute this dust world wide.

Dust particles are very small, called 'fines', and would irritate human lungs (even if the dust didn't contain perchlorates, which are poisonous).

Dust composition

The Martian dust is weathered from primarily volcanic rocks. This can be from mechanical weathering of basalts. But when basalt weathers in water if forms feldspar, and some dust is composed of feldspars.

Volumetrically Martian dust is dominated by composites of plagioclase feldspar and zeolite.

A small percentage of the dust is from powdered salts, of which the most dangerous is Perchlorate ( ClO-4 ), which is toxic.

Elemental Dust Composition Using Alpha-Particle X-ray Spectrometer

Molecule	Chemical Name	Average Martian Soil by %	Uses
SiO2	Silicon Dioxide	45.41	Glass
TiO2	Titanium(II) oxide	0.90	Paint & cosmetics
AlO3	Alumina or aluminum oxide	9.71	Ceramics
FeO	Iron oxide or rust	16.73	Iron & Steel
MnO	Manganese(II) oxide	0.33	Fertilizer & food additives
MgO	Magnesium oxide or magnesiae	8.35	Antacid & alloys
CaO	Calcium oxide or quicklime	6.37	Cement, paper, steel
Na2O	Sodium oxide	2.73	Glass & ceramics
K2O	Potassium oxide or pure potash	0.44	Fertilizer, glass, soap
SO3	Sulphur trioxide	6.16	Sulphuric acid
Cl	Chlorine	0.68	Chemical processes as a strong oxidizer
	Total	97.81	Remainder unidentified

Dust size

These are generally very small, only 3 micrometers in diameter. This is so small it will enter lungs and irritate them, being difficult for the cilia to remove. Good dust filters will be wanted in a Martian base, and waterfalls and pools may be wanted to help remove dust that enters a habitat.

Dust this small will wear moving parts. Any moving parts outside must be carefully sealed to prevent dust from getting into the joints.

Making bricks from dust

Poor quality bricks can be made with simple compression, tho stronger bricks can be made with gentle heating. See Brick for more information.

Dust reducing the effectiveness of solar cells

Dust storms can last weeks or months and reduce the amount of light hitting the ground by up to 95%. (Tho 30 to 60% is typical.) See Dust Storms for more information.

The atmosphere is dusty, and NASA has found that solar cells soon get covered by enough dust to reduce their effectiveness. This is typically 0.2% per Sol, tho 0.5 to 2% per Sol has been observed at some times.

The dust is sticky and resists being wiped clear, even if the cells are dusted off, they will still be reduced by about 1% to 2%. If washed clean they can be restored to 100% power.

This dust can be removed by dust devils, or strong winds. This varies greatly by location; areas with strong winds and low boundary layers are more likely to have significant cleaning. The Spirt rover was well cleaned by dust devils (Opportunity less so) but the Insight lander got no significant cleaning of its panels.

Earth solar cells do not have this problem for the most part. Earth is less dusty, and cells are well cleaned by occasional rain storms.