The fourth planet from the Sun, a cold, thin-atmosphere world with iron-rich regolith and about a third of Earth's surface gravity.
Chinese researchers made a 3D-printable 'living cement' from engineered yeast, gelatin and sand that reached 12 MPa of compressive strength. So far, its promise of Mars shelters printed from local dirt rests on tests with sand and on gelatin that would have to be launched from Earth.
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Tohoku University researchers and colleagues modelled early Mars's formaldehyde rain, putting about 10 times the global average on Tharsis and Elysium. The prediction links where a raw material for sugars and amino acids landed to the planet's ancient water cycle.
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University of Copenhagen researchers estimate at least 75% of Earth's mass came via pebble accretion and about three-quarters of Mars' from planetesimals. On this evidence, rocky neighbours can grow by different routes, though the models have to assume what the building blocks were made of.
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A Nature paper puts the boundary between stiff and soft Martian mantle directly beneath the surface dichotomy. The authors still keep a giant impact on their list of causes.
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Work presented at the European Geosciences Union assembly in Vienna models whether compressed rock sits beneath Phobos' largest crater, part of an effort to read the little moon's interior before Japan's MMX mission goes there to sample it.
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Drones, satellite elevation models, boreholes and geophysical profiles put zones of broken rock beneath trenches up to 20 kilometres long, and the authors say the same signature could find caves on other planets.
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Isabel Herreros and Sebastien Charnoz have modelled how self-gravity, Martian tides and rotation move loose material across Phobos, because on a moon that small a downhill slope does not predict which way regolith goes.
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Jishen Qiu's team let Mars-like cold and vacuum do the hardening, printing cork-sized domes with the compressive strength of low-grade concrete. The imported gelatin and yeast are what the method still costs.
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