VARIOUS AREAS OF POSSIBLE DEVELOPMENT FOR SPACE ECOSYSTEMS
The most important part of a closed ecosystem is the enclosure itself. It must be structurally strong to protect its inhabitants from natural phenomena like heavy dust winds and must also have safety mechanisms to protect from intense solar radiation. It should be pressurized in order to match the atmospheric pressure on earth. It must have temperature control mechanisms in place to suit human life. Another use of the exterior would be to house solar panels to generate electricity.
It is a well-known fact that human beings require oxygen in order to convert food into energy. So, the presence of enough concentration of oxygen in the air is a key element of the ecosystem. The most popular method to produce oxygen is by splitting water into hydrogen and oxygen gas by a process called electrolysis. Once the required amount of oxygen is being generated and a small forest is created, we can rely on photosynthesis. Another method would be to convert carbon-dioxide into oxygen but such methods are not viable currently.
The human body comprises of 60% of water and we have consume about 2 to 3 liters of it per day. Although there is no concrete evidence to support the latter claim, we still have to stay hydrated to keep our body functioning properly. Initially, we can use the Sabatier reaction which uses a nickel catalyst that reacts with carbon-dioxide and hydrogen at elevated temperatures and pressures to produce water and methane. This reaction can work in conjunction with the previously mentioned electrolysis in order to remove the by-product hydrogen gas . Later, we can switch to recycling used water as the Sabatier reaction requires some energy to start.
Once the setup of oxygen and water is complete, food becomes the most important priority. As the workload to maintain the ecosystem will be high, so will be the amount of food to be produced. Since the soil on other planets lacks the minerals required for plants to grow, we have to enrich it. The easiest way to do so would be to recycle human waste and use it as a fertilizer. Another challenge would be to create and sustain artificial nutrient cycles but it can be done by introducing nitrogen-fixing bacteria into the soil.
Once the initial supply of resources runs out, recycling plants play a crucial role in replenishing resources. There is a need for water recycling as well as waste recycling plants as stated above. Such systems already exist aboard the International Space Station and are being used extensively . Once the technology is developed, oxygen recycling can also be done to create a self-sustaining environment. A proposed method to acquire more resources is called in situ resource utilization which states that space habitats may be supplied with resources from extraterrestrial places like asteroids or the moon .
In order to run all the electronics along with the life-support systems in the system, it is mandatory to have a continuous and uninterrupted supply of energy in the form of electricity. Because of limited availability of resources, it is better to reply on renewable sources of energy. Solar panels can be used to generate electricity but it is not a completely reliable technique on a planet like Mars which receives only 60% of what the earth receives from sunlight because it is farther away. One potential solution is using geothermal energy initially by drilling into Mars’ surface and then switching to nuclear power once the required infrastructure is established.
The efficient intertwining of all the mentioned components along with impeccable effort from the inhabitants to maintain it will ensure the success of the ecosystem and enable us to think about expansion.