Acidalia Planitia

Lore & Background

In the 2011 novel The Martian by Andy Weir, and its 2015 film adaptation, Acidalia Planitia is the landing site of the Ares III mission, where the protagonist is stranded following a dust storm. The plain's geological history includes several hypotheses: it was once covered by ancient crust, its surface eroded into knobs of iron/magnesium phyllosilicates during the Amazonian, and sediments filled the empty plain, leaving the phyllosilicate knobs as protrusions. Hydrated silica materials surround these knobs, indicating the plain was once home to springs and steam vents, not extensive bodies of water. Craters on Acidalia Planitia are asymmetrical, with MOLA data showing pole-facing crater walls are shallower than equator-facing slopes, suggesting either biased glacial deposition during the Amazonian or long-term creep of ice-rich regolith. Cone-shaped features with higher albedo than surrounding rocks litter the surface, resembling terrestrial mud volcanoes, with an average diameter of ~1 km and relief of 10 to 180 meters.

In Their Own Story

The wind howled across the plain, a thin, relentless whisper of carbon dioxide. Mark Watney stood at the edge of the Hab's airlock, his suit's visor reflecting the endless rust-colored expanse. He had named a nearby crater 'Watney's Crater' in a moment of dark humor, but the plain itself offered no comfort. Every morning, he watched the sun rise over the distant hills, knowing that each day was a battle against the cold, the radiation, and the crushing isolation. The plain was his prison, his garden, and his only witness — and he would not let it have the last word.

Reader's Guide

Acidalia Planitia is the central setting of The Martian, representing both the harsh reality of Mars and the stage for human ingenuity. As the Ares 3 landing site, it is where the crew's mission is cut short by a violent dust storm, leading to Mark Watney's accidental abandonment. The plain's flat, boulder-strewn surface becomes his home for over a year, where he cultivates potatoes in Martian soil, repairs equipment, and communicates with NASA. Its role is dual: a symbol of desolation and a canvas for survival. The plain's proximity to the Schiaparelli crater and its subsurface ice deposits are key to Watney's water production and eventual rescue. For fans, Acidalia Planitia embodies the unforgiving beauty of Mars and the triumph of human resilience against a barren world.

Did You Know?

• Acidalia Planitia is centered at 49.8°N 339.3°E, between the Tharsis volcanic province and Arabia Terra.
• The plain is named after a corresponding albedo feature on a map by Giovanni Schiaparelli, which was named after the mythological fountain of Acidalia.
• Some places in Acidalia Planitia show cones that some researchers have suggested are mud volcanoes, with an average diameter of ~1 km and relief of 10 to 180 meters.
• Hydrated silica materials surrounding phyllosilicate knobs indicate the plain was once home to springs and steam vents, not extensive bodies of water.
• In the 2011 novel The Martian by Andy Weir, and its 2015 film adaptation, Acidalia Planitia is the landing site of the Ares III mission.