Water
Water usage on Mars for the first colonist is going to be a key issue.
Initial Water usage
Drinking
Food rehydration for rations from Earth
Hygiene
Equipment use and Space suit usage
Cleaning and flushing
A very big use for the initial colonists will be cleaning clothes
Hydroponics
production of Fuel
Water Sources on Mars (From NASA “Mining” Water Ice on Mars PDF )
• Atmospheric Water Vapor – 100 percent relative humidity has been observed on Mars but the atmosphere is very thin so available water is very small
• Ground Water – Defined as liquid water in subsurface deposits (e.g., aquifers) – this category includes gullies and recurring slope lineae (RSLs)
• Adsorbed Water – Thin film of water coating individual grains of regolith/soil
• Hydrated Minerals – Water either chemically bound or incorporated in the crystalline structure of minerals
• Ice – Polar caps – Subsurface layers – “cryosphere” (e.g., permafrost, ice lens, pingos, etc.) – Glacier-like forms in mid-latitudes and a few equatorial areas
Most of the water on Mars is at the polar regions which at first will be inaccessible to the initial colonist, Glacial ice is a very good source of water but is found predominantly near the poles, that are far from locations to set up initial colonies, most likely 100s Km away. As the colony grows that will be the way support them as they get larger towards 'Musk city'.
The quickest way to start with is to find locations where localized remnant deposits or icey meteoroids using Surface mining of ice, first clearing away debris layer.
Just to melt enough Ice at -80°C for water to support a crew or 12 will need around 40KW continuously, extracting the Ice will use a lot more power.
Storage of water will be critical, most likely in tanks that allow the water to freeze, how to store water above ground particularly long term storage is a problem that needs to be solved on Mars.
Mining Water Ice on Mars
Technique to extract ice – Remove debris layer and then remove ice (e.g., open pit mine) – Drill through debris layer and create a subsurface reservoir of liquid water
• Conduct a local site survey to identify the specific locations
– Identify the thinnest debris depth
– Determine the firn* layer depth (if any) and identify cracks, voids, etc.
• Drill through the debris layer
– Use mechanical drill
– Case the hole to prevent debris from collapsing into the hole and to allow some TBD
pressurization of the reservoir
• Drill into ice layer
– Drill down to a depth sufficient for ice to support the overlying debris layer and bypass any firn, cracks, voids, etc.
– Several technology options exist for this step; further evaluation/tests are needed to select “best” option
• Mechanical, electro-thermal, hot water, hybrid
• Melt ice and store water in subsurface reservoir
– Power needed to melt ice and water extraction rate are coupled and both are tied to the specific use scenario
* Firn: crystalline or granular snow, especially on the upper part of a glacier, where it has not yet been compressed into ice.
Buried ice: Where to find Ice away from the polar regions
Due to the low pressures in the Martian atmosphere, and the temperatures in equatorial regions, ice can “sublime” directly from the solid to gas state (evaporation being the transition from water to gas). So looking for the features that protect ice under a layer of debris is a possibility.
The Protonilus - Deuteronilus Mensae region on Mars is located in the northern mid-latitudes of Mars (~8°E and 60°E 38N and 50°N), This region is host to numerous land forms which appear to contain large buried ice deposits, hundreds of meters thick and several kilometres wide.
Finding locations nearer the equator will help solar power and the need for warmth for any surface habitats. (SEE Exploration Zones)
Once water has been extracted and purified it will need to be distributed; maybe as ice, kept frozen until needed. Making a drink on Mars will start by melting the ice.
External link to NASA Buried Ice article