Atmosphinder harnesses Martian winds to observe CO2 gas jet expulsions in the southern polar region for environmental science on Mars.
Why is this important?
⚠️ To date, there have not been observations of a plume in action! [5]
⚠️ There are puzzles that remain in the understanding of the CO2 gas jet process
⚠️ By investigating this on the surface of Mars, the information could be validated with on the ground data
What are the CO2 jets?
Sublimation of frozen CO2 to gas creates ‘jets’ from vents that have formed. The jets expel plumes of sediment from underneath the ice layer. The fans and blotches that have been seen from satellite imagery is evidence of this process.
Plumes reaching 100 meters occur daily during the Mars south pole spring season. After the ice cap recedes, spider-like patterns are found in the sediment from channels of the gas, known as araneiforms. The process repeats year after year, with some hypothesis that the activity is linked to Mars’ global dust storms.
Why are CO2 jets relevant?
Orbital studies from High Resolution Imaging Science Experiment (HiRISE) on Mars Reconnaissance Orbiter (MRO) have shown that winds transport fine-grained sediments across Mars [19].
Image source: [20], NASA Goddard Media Studios
This similar impact can also be seen on Earth with grains of sand being transported from the Saharan desert to the Amazon rainforest [20].
This environmental process is significant because nutrients are transported for plant proteins and growth [20] across vast distances as demonstrated by the Earth example.
Science Objectives
1. Observe a plume in action, recording the duration, height, and apparent particle size
2. Conduct a visual survey of the debris from previously erupted jets
3. Characterize the troughs, seasonal boundary zone, and layered terrain
A concept rover, Atmosphinder, is proposed to conduct these science objectives. The outcomes would provide a ground truth to existing satellite imagery by capturing photos from the surface and an aerial view.
Photography from the aerial view is well suited for several of these activities, as a similar technique has been used on Earth to map periglacial geomorphology for analyzing ice networks [24].
How do the CO2 jets form?
Image source: [4]
The process is known as the solid state greenhouse effect [1, 5]. This occurs after the seasonal CO2 has frozen, forming an impermeable slab of translucent ice [2].
Approximately 70% of the sunlight reaches the subsurface [2, 3], which then heats up the sediment and regolith underneath [4].
The thermal radiation cannot escape. The pressure is building, causing a portion of the slab to levitate [4] momentarily, until finally the ice ruptures and forms a vent [5].
A massive plume escapes from the vent containing gas and grains of sediment [5], reaching 100 m [6].
As the eruption subsides, the dust settles onto the surface in the form of fans and blotches [5].
The understanding of the CO2 jet process stems from the “Kieffer” model [2, 7, 8, 9], with information from numerous Mars instruments, primarily from the Mars Reconnaissance Orbiter (MRO) High Resolution Imaging Science Experiment (HiRISE) [2, 10].