Composition of Mars' Atmosphere

About This Dataset

This chart shows the composition of the Martian atmosphere by volume. Unlike Earth's nitrogen-oxygen air, Mars has a thin atmosphere dominated by carbon dioxide, with almost no free oxygen.

✨ AI Insight

Mars's atmosphere is overwhelmingly carbon dioxide (about 95%), a stark contrast to Earth's nitrogen-oxygen mixture. Nitrogen (2.8%) and argon (2%) make up almost all of the remainder, while oxygen is a mere 0.174%, far too little to breathe. Combined with a surface pressure less than 1% of Earth's, this composition leaves Mars cold and inhospitable to unprotected life. Carbon monoxide (0.075%) and highly variable water vapour (around 0.03%) round out the trace gases. The dominance of CO2 reflects the absence of a global carbon cycle and photosynthetic life to convert it. The scarcity of oxygen is exactly why crewed-mission plans call for manufacturing oxygen locally, an approach NASA's MOXIE experiment on the Perseverance rover demonstrated by splitting Martian carbon dioxide.

Source: NASA / Atmosphere of Mars

Key Findings

Auto-computed highlights from this dataset

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Carbon Dioxide leads with 95 in All Time.

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Average value in All Time: 17 · median: 1.

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Gap in All Time: Carbon Dioxide is 3166.7× larger than Water Vapor.