How can you colonise Mars without sending humans? You only need three instruments: a rover, a bioreactor and a 3D printer.
An iron-producing bacterium could be the key to the desired colonisation of the red planet without the need to send space missions with humans, at least in the early years. This ambitious plan has been developed by the PhD student at the Delft University of Technology (Netherlands), Benjamin Lehner.
With this project, it would only be necessary to send a rover, a bioreactor and a 3D printer to start colonising Mars.
Why is this idea so interesting?
When it comes to planning future space missions, one of the most important aspects is the use of local resources and autonomous robots. This process is known as In-Situ Resource Utilisation (ISRU), which reduces the amount of equipment and resources that must be sent or brought by a mission crew. In the meantime, autonomous robots can be dispatched long before the crew and have everything ready when they land.
In this way, the bacteria can extract iron from the extraterrestrial soil, which would then be used to print 3D metal components that would serve to build a Martian base.
In his thesis, Lehner proposes the deployment of an unmanned mission to Mars that will convert regolith into usable metal using a bioreactor filled with bacteria, which would allow the creation of Martian habitats for missions without the need for crew present sending supplies in advance.
How exactly would that be done?
A rover, basically a robotic shovel, will take the soil to a bioreactor full of bacteria, which will consume the iron-rich but unusable soil and digest it into a more useful oxide. After that, a 3D printer can make tools and anything future settlers might need.
Sowing Mars with bacteria would have one drawback: it would completely ruin astrobiologists' attempts to find traces of extraterrestrial life on the planet. To avoid contamination between planets, Lehner designed a closed-loop system - a sealed chamber - to collect Martian soil, extract minerals and turn them into useful materials such as screws, nuts, iron plates, etc. Without contaminating the soil of Mars.
Inside the bioreactor, bacteria would feed on microalgae, which will depend on sunlight and CO2 from the Martian atmosphere to create nutrients and oxygen. They also produce residual organic waste, which the first astronauts on Mars will be able to extract and use as compost.
Another point to keep in mind would be time. Lehner and his team calculated that a 1400-litre reactor can produce up to 350 kg of material in one year. Although it is a good idea it is a slow process, as the work suggests that it would take years for the bacteria to produce enough iron to be useful, so we could not take it as a rapid response plan to the current challenges of space colonisation.
And this is assuming that the proposed terraforming system that is actually feasible.
International Space Station
A very similar idea is currently being investigated aboard the ISS, a bioreactor that relies on algae for life support and a constant supply of nutrients. When missions to the Moon and Mars become frequent, it will be common to see robots equipped with 3D printers.
Reference : 'To new frontiers, microbiology for nanotechnology and space exploration' doi.org/10.4233/uuuid:acd7102b- ... b5-972e-fe3a2ad9c52e