Mars Habitat

Essentially a Mars habitat needs to protect its inhabitants from the following adversities:

1. toxicity near to vacuum low-pressure atmosphere 2. extremely low temperatures 3. life threatening cosmic radiation 4. meteorite impacts

Furthermore the mass of transportation inside the spaceship should be as little as possible and we want to make use of natural sunlight for spacious greenhouses. Greenhouses are important not only for production of food and oxygen through photosynthesis but with vegetation it will be the only natural environment for the inhabitants, who will not be able to leave their habitat more than a few minutes per day in their space suits due to the hard radiation outside. Spending most of the time in a small sterile room without sun and plants could lead to depression.

We hereby present the concept PNEUMO PLANET that masters these challenges in the following way:

Extra light inflatable membrane modules will be manufactured and checked on Earth under optimal conditions and then brought to Mars. The membrane material features the required airtightness and tensile strength to hold the inner atmospheric pressure, and it can be transparent as well. Since homogenous transparent ETFE membrane does not show the same tensile strength as opac fibre reinforced material, it will get an extra support by a net of highly durable Dyneema ropes. Ropes spanned inside also can help to achieve a wide low cross section shape, that is different from a pure circular outline ,that it would have without any additional support. We already have successfully applied the reinforcement with ropes on my inflatable structures on Earth.

All the rest of the building material that shall protect from freezing temperatures, radiation and meteorites shall come from the Mars surface as sand and stones (regolith), which will be deposited on top of the inflatable structure with an excavator or through manpower with shovels. Unlike 3D-printing, depositing loose material is a very simple, reliable and quick method.

Since the atmospheric pressure on Mars is 6 mbar only (while 1008 mbar on Earth), an inflatable structure inflated up to 500 mbar (which is the same as at 4000 meter above sea level on earth) will be as tight as a car tyre and can support up to a 5 meter thick layer of regolith.

We have a solution for greenhouses that has not been part of any previously published Mars habitat concept:

The side walls shall be transparent and free of deposit. To protect the side walls from radiation and meteorites, overhanging roof is installed which stop any direct sun radiation on the equator that could come from an angle deviating from vertical +25,44° to -25,44° South – North direction in summer and winter. The tubular inflatable modules span from East to West.

Parallel along the transparent sidewalls we install mirror membranes that reflect the visible light into the greenhouse while the hard radiation penetrates the mirror membrane and is absorbed in the ground below. The angle of the mirror membrane can be adjusted so it can follow the seasonal declination of the sunlight.

The pneumo planet design solves these issues by reflecting the visible sunlight into the habitat with mirrored membranes while the hard radiation penetrates the mirror and is absorbed into the ground below. The deposit on the ceiling and on the embankments on the sides shields from unwanted radiation and micrometeorites

As an extra safety feature the membrane is double layered. Both layers are welded grid-like so the space between them is divided into single airtight cells. So a puncture of the membrane always can affect on cell only. Due to gravity the mirror membranes are bent in a flat parabolic curve, so the sunlight from a much larger mirror area can be focused into the greenhouse. This can compensate the weaker sunlight compared to the sunlight on earth. On the transparent sidewalls there is a third layer of membrane. Since on Mars the air pressure from outside on the 3rd membrane layer is very little, the space between the 2nd and 3rd layer can be evacuated. With that vacuum the heat loss trough convection and transmission can be reduced to almost zero.

Watch the YouTube video that explains all of the habitat

Watch the YouTube video of the small mock up

How to build

The assembly can be done quickly with simple and reliable technology. The modules are unraveled, stretched on a flat ground and covered with loose regolith. In order to avoid erosion of the regolith, it can be poured in to thin bags beforehand. Then the module is inflated and automatically lifts the regolith deposit. Parallel to the module the mirror membranes are installed on embankments, which protect from meteorites and cosmic radiation which enter in a flat angle

The 96% of CO2 present in the atmosphere on Mars is toxic for plants. Also the regolith, that is used as substrate for plants, needs to be cleared of toxic perchlorates. At night when temperature drops to minus 60°c, air extracted from the atmosphere will be compressed to 15 Bar, so the CO2 liquifies and can easily be separated from the other atmospheric gases, which are blown into the module for inflation. This results in an inner air consisting of 48% Argon, 48% Nitrogen and 3,6% Oxygen. The rest of the carbon monoxide oxidizes to CO2.

The toxic perchlorates in the regolith are decomposed by bacteria. At the first arrival of astronauts, the regolith will be fertilized with the human excrements accrued during the 8 months of spaceflight. Thus we create the appropriate conditions, where plants in symbiosis with fungi, microorganisms and later. when the percentage of O2 has raised through photosynthesis, insects can prosper.

The greenhouse units are connected grid-like via inflatable tunnel modules and toroidal interconnecting modules, which host rooms for living, work and storage. Air locks and large halls and power plants complete the Mars village. In case a module is irreparably damaged, it will be disconnected from the rest of the compound in which the other modules stay connected and work in order. If an air leak occurs, the inflatable modules are safer than a rigid building.

The inner air pressure is 500 mbar, while 250mbar are need only to support the weight of the ceiling and deposit. Thus 50% of the air need to stream out before the load capacity of the structure is affected. From that moment on the ceiling goes down slowly under the weight of the deposit, while the inner air pressure remains at a stable 250mbar because the weight on the ceiling compresses the inner air to that pressure. These 250mbar provide the minimal standard of breathable air.

The inhabitants have considerable time to seal the leak or leave the module before the ceiling goes all way down. After the repair, the module gets re inflated up to 500 mbar and erects itself. Whereas in a conventional rigid building, the air pressure would drop below 250 mbar, which leads to the dead of humans and plants inside, or the ceiling would break under the load without the support of inner air pressure.

The traffic system of a Mars Village compound consists of double tubes. In case one inflatable tube element is damaged it can be bypassed through its twin brother tube

Inflatable Modules

Large convention hall: A net of ropes gives extra structural support and brings the membrane in the right shape. since the rope net divides the area of the membrane into smaller sections, the membrane material only needs to hold the inner pressure of the smaller area within a frame of ropes.

To keep the transportation mass as low as possible, the inner partitioning walls, furniture and facilities as shower cabin. sinks and toilet, are modular inflatable elements as well. The inhabitants can quickly install these elements and can change their position whenever they

like. The space is divided into a geometric grid, where few wall element types fit into various positions and are fixed with nylon zippers and inflated.

Soft walls minimize the risk of injury even when passage ways are narrow. They also look cosy and are nice to touch. The entrances to the bedrooms and living rooms do not feature heavy rigid door wings, but inflatable lips through which inhabitants slip through. Shower cabins are not made of rigid panels but of transparent membrane spanned from the floor to the ceiling.

Hard panels for shelves, tables and floor panels can be made of carbon fiber. Shelves can be suspended from the ceiling or toilets and sinks. It can be formed of airtight membrane envelopes filled with Mars-sand outdoor at 6 mbar pressure. Taken inside the air presses on the envelope with a force of 5000kgs / m2, so the grains of sand are compressed into a rigid piece of the right shape defined by the envelope.