In this video we will try to imagine some of the technologies
that could help first astronauts in the hypothetical colonization of Mars.
We will try to understand the problems they might encounter and the possible countermeasures.
The first big problem is to reach Mars alive: for a very long time, equivalent to no less than six
or seven months, the crew would be completely exposed to abundant quantities of cosmic rays
and ionizing radiation, the effects of which, in the long run, could be deleterious to the
health of the organism, with a consequent high probability of developing serious diseases.
How to solve the problem by avoiding very heavy lead and massive radiation shields?
At the Ames Research Center, California, they have developed and are testing a compactor
that takes the daily non-organic waste produced in flight and converts it into a disc about 20
cm by 1.5 cm thick, which can be used to compose a light and very useful cosmic ray
shield on the walls of the space capsule. A kind of tile in size which, thanks to the prevalence
of plastic compacted at least 10 times in its constitution, can absorb the dreaded radiations
and particles that run through the spaces between planet and planet. By carpeting one
of the spaces of the spacecraft, for example the sleeping area or even creating a "refuge" area
to be used for short periods in the event of a violent eruption by the Sun, astronauts could be
protected without having to carry the weight of a traditional shield made of thick metal.
It could reasonably be objected that the waste could be thrown out of the capsule,
an effective solution although certainly not elegant and contrary to NASA ethics:
full of bacteria and other potentially pathogenic agents, like everything in contact with humans,
they could contaminate other planets. What would you do about it? Write it in the comments!
The compactor is quite small and brings the material to a temperature of 150 degrees
for three and a half hours, a procedure sufficient to eliminate any microorganism,
but not too energetic to risk burning the material itself. To make a 20-centimeter round shield tile,
you need half a kilo of typical material for life in space, such as water bottles, plastic tape,
food wrappers, aluminum and foil packaging. There remains the problem of understanding how long the
compressed material can last and above all, given that it is used to upholster environments in which
humans stay for months and months, if a healthy or at least neutral environment is created.
This system would also solve at once another important problem related to space missions,
namely the storage of waste produced by the crew.
An alternative project proposed by NASA is Water Walls,
which plans to use drinking or waste water to protect astronauts from cosmic rays.
According to Marco Durante of the Technical University of Darmstad,
water is better than metal as a protection because nuclei are responsible for blocking cosmic rays
and water molecules, made up of three small atoms, contain more nuclei per volume than metal.
Furthermore, the water used as a shield can be drunk without danger,
even if it has been extracted from human urine and feces:
Water Walls, in fact, involves the use of polyethylene bags which, through an osmosis
process, will purify the water, constantly supplying astronauts with drinking water.
These bags will form a 40 cm thick protective layer, and will initially be filled with potable
water which will gradually be replaced by water recycled from the crew's organic waste.
The Water Walls project also involves the use of bags capable of purifying the
air from excess carbon dioxide, regulating the temperature of the shuttle or creating
micro-habitats for the growth of plants and algae. However, many problems still remain to be solved.
Although the bags have already been tested in orbit during the Shuttle's last flight,
their effectiveness in a microgravity environment is 50%
of that demonstrated on Earth, not enough to keep a crew bombarded by constant doses
of radiation alive. cosmic. In the case of solar flares,
probably not even a ten-foot-thick concrete shield would be able to protect astronauts,
explains Ruth Bamford, a researcher at the Rutherford Appleton Laboratory and responsible for
the design of a magnetic solar radiation shield. To overcome this inconvenience, the last stage
of the launch rocket could be kept attached to the shuttle,
orienting it towards the Sun during events involving substantial emissions of radiations.
Once landed on Mars, astronauts will have to face another important problem:
the production of energy and bio fuels for the missiles that will be used to return to Earth,
exploiting as much as possible the resources in situ: carbon dioxide, sunlight and ice water.
According to a process described in an article in Nature Communications, two terrestrial microbes
would also need to be imported to Mars to start the bioproduction process: cyanobacteria,
which would absorb CO2 from the Martian atmosphere and use sunlight to create sugars;
and Escherichia coli designed to convert those sugars into a specific propellant for rockets
and other propulsion devices. This combination already exists on Earth and is called
2,3-butanediol: it has formula (CH3CHOH)2 and is used to produce polymers in the rubber industry.
Current rocket engines, which will reach Mars in the near future, are powered by methane and liquid
oxygen (LOX) but neither exists in abundance on the Red Planet. This means that astronauts would
have to receive them from Earth to return home. But the transport is very expensive:
it is estimated that the journey of 30 tons of methane and LOX costs about 8 billion dollars.
NASA and other studies have suggested some alternatives to derive the two elements
on the spot but these technologies are still immature to work on a large scale.
The Georgia Institute of Technology's proposal calls for in-situ resource
utilization based on biotechnology that can produce both propellant and LOX from CO2.
The process would also return 44 tons of excess clean oxygen that could be stored for other
purposes, such as supporting human colonization. First of all, plastic materials would have to be
transported to Mars to build photobioreactors the size of four football fields.
Cyanobacteria would grow in reactors via photosynthesis (which requires carbon dioxide).
The enzymes, in a separate reactor, would break down the cyanobacteria into sugars for Escherichia
coli, from which the rocket propellant would be obtained. This would be separated from the
fermentation broth with advanced techniques. If for some reason this process fails, and
therefore it is impossible to return to Earth, how would you behave? Write it in the comments!
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Pamela Peralta-Yahya, one of the study’s author and professor at the School of
Chemistry & Biochemistry and ChBE who engineers microbes for the production of chemicals,
argues that this process needs much less energy to take off from Mars, which has given the
flexibility to consider different chemicals that are not designed to launch rockets to Earth. Ways
to exploit the planet's lower gravity and lack of oxygen have begun to be considered to create
solutions that are not relevant to Earth launches. The team is now looking to perform biological and
material optimization identified to create a linear and fast process. For example,
improving the rate at which cyanobacteria grow on Mars would require a smaller and smaller
photobioreactor, significantly lowering the payload needed to transport equipment from Earth.
However, experiments still need to be performed to show that cyanobacteria can actually be grown
under Martian conditions, and to consider the difference in the solar spectrum on
Mars due to both the distance from the Sun and the lack of atmospheric filtering of sunlight.
High levels of ultraviolet could damage cyanobacteria.
Another issue of fundamental importance for the survival of a human crew is the production of
oxygen. The Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE), mounted
on the Perseverance rover, has shown that the production of oxygen from the Martian atmosphere
is possible. For the future of Mars exploration, oxygen will be a crucial element, not only for
the life support of astronauts. The rockets in fact also work powered by liquid oxygen,
and to leave the red planet it is necessary to be able to produce the propellant locally.
MOXIE extracted 5 grams of oxygen from the Martian atmosphere for the first time.
This is another historical moment for space exploration, but how is it possible to extract
oxygen from an atmosphere that does not have any? Only 0.16% of the Martian atmosphere is
in fact composed of oxygen (O2 to be precise) but this is not what MOXIE has extracted.
The NASA instrument, activated for the first time on April 20th during Sol number 60,
collected carbon dioxide (CO2), which represents 96% of the atmospheric composition.
Once it collected CO2, MOXIE has broken it down, collecting oxygen and releasing carbon monoxide
into the Martian atmosphere. The experiment is another technological demonstrator,
as the Ingenuity helicopter is therefore not a real scientific experiment.
The experiment is placed inside the Perseverance rover, and is about the size of a toaster,
weighing 17 kg. As mentioned, the goal is the conversion of carbon dioxide into oxygen
and carbon monoxide. The first is stored, the second expelled into the atmosphere.
With this first activation of MOXIE, 5.37 grams of oxygen were produced. This amount is equivalent
to about 10 minutes of breathing air, but MOXIE was designed to produce up to 10 grams per hour.
To carry out this conversion, it uses solid oxide electrolysis, compressing and heating
the Martian atmosphere. This process requires particularly high temperatures, which reach
800 ° C. The whole structure of MOXIE is therefore carefully built to support these temperatures
and to isolate them as much as possible so as not to damage Perseverance. Some components are
made by nickel alloy, which support both heating and cooling of the collected gases. There is also
an external golden coating, to reflect infrared radiation and prevent them from radiating outside.
MOXIE will now operate in three different phases, to test it in as many conditions as possible.
First of all, the condition and operation of the instrument itself will be checked,
and the production just carried out is already an excellent first result. Then the test will
be repeated in different weather conditions, such as different times of day or season. In
the third and final phase MOXIE will be taken to the limit, testing it with different temperatures.
NASA has estimated that four astronauts will need about 7000 kg of fuel,
and 25000 kg of oxygen to leave Mars. It is unlikely that 25 tons of oxygen
could be brought to Mars directly from Earth. A stay of one year on the planet
would instead involve the consumption of about a ton of oxygen by the astronauts.
For this reason, NASA itself is already thinking about the successor to MOXIE, a
similar experiment, but scaled in size. A similar instrument, weighing one ton, could produce
about 1 kg of oxygen per hour. Such an instrument could produce 25 tons of oxygen in 3 Earth years.
It would be enough to have five or six of these devices to reduce the time to six months.
Another technology that cannot be missing from manned Martian missions is a 3D printer:
given that shipments with supplies will arrive every 26 months, the astronauts will have to
be completely self-sufficient and able to build spare parts and tools on their own.
A group of engineers from Northwestern Engineering's Tissue Engineering and
Additive Manufacturing Laboratory demonstrated the feasibility of
producing objects using synthetic replicas of lunar or Martian dust.
Using Martian regolith, a series of simple solvents and a biopolymer,
it is possible to make special 3D printer inks to print a series of LEGO-like bricks.
The synthetic dust particles used in the laboratory have a composition, shape and size very
similar to those of the Moon and Martians. The 3D objects (tools and bricks) were then printed
with a simple extrusion process. These similar bricks can then be used as building elements.
The researchers assure that the tools produced with this method are flexible, elastic but at the
same time robust. The material can be manipulated, cut or wound and is very similar to rubber.
In short, it could be suitable for use on the planet Mars. The next step will be to make this
material as hard as ceramic and the only possible way is to cook it as it is done on Earth in ovens.
What other new technologies come to your mind for the colonization of Mars?
Write it in the comments!
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