Transporting a single brick to Mars can cost more than a million British
pounds—making the future construction of a Martian colony seem prohibitively
expensive. Scientists at The University of Manchester have now developed a
way to potentially overcome this problem, by creating a concrete-like
material made of extra-terrestrial dust along with the blood, sweat and
tears of astronauts.
In their study, published today in Materials Today Bio, a protein from human
blood, combined with a compound from urine, sweat or tears, could glue
together simulated moon or Mars soil to produce a material stronger than
ordinary concrete, perfectly suited for construction work in
extra-terrestrial environments.
The cost of transporting a single brick to Mars has been estimated at about
US$2 million, meaning future Martian colonists cannot bring their building
materials with them, but will have to utilize resources they can obtain
on-site for construction and shelter. This is known as in-situ resource
utilization (or ISRU) and typically focusses on the use of loose rock and
Martian soil (known as regolith) and sparse water deposits. However, there
is one overlooked resource that will, by definition, also be available on
any crewed mission to the Red Planet: the crew themselves.
In an article published today in the journal Materials Today Bio, scientists
demonstrated that a common protein from blood plasma—human serum
albumin—could act as a binder for simulated moon or Mars dust to produce a
concrete-like material. The resulting novel material, termed AstroCrete, had
compressive strengths as high as 25 MPa (Megapascals), about the same as the
20–32 MPa seen in ordinary concrete.
However, the scientists found that incorporating urea—which is a biological
waste product that the body produces and excretes through urine, sweat and
tears—could further increase the compressive strength by over 300%, with the
best performing material having a compressive strength of almost 40 MPa,
substantially stronger than ordinary concrete.
Dr. Aled Roberts, from The University of Manchester, who worked on the
project, said that the new technique holds considerable advantages over many
other proposed construction techniques on the moon and Mars.
"Scientists have been trying to develop viable technologies to produce
concrete-like materials on the surface of Mars, but we never stopped to
think that the answer might be inside us all along," he said.
The scientists calculate that over 500 kg of high-strength AstroCrete could
be produced over the course of a two-year mission on the surface of Mars by
a crew of six astronauts. If used as a mortar for sandbags or heat-fused
regolith bricks, each crew member could produce enough AstroCrete to expand
the habitat to support an additional crew member, doubling the housing
available with each successive mission.
Animal blood was historically used as a binder for mortar. "It is exciting
that a major challenge of the space age may have found its solution based on
inspirations from medieval technology," said Dr. Roberts.
The scientists investigated the underlying bonding mechanism and found that
the blood proteins denature, or "curdle," to form an extended structure with
interactions known as "beta sheets" that tightly holds the material
together.
"The concept is literally blood-curdling," Dr. Roberts explained.
Reference:
Aled D. Roberts et al, Blood, sweat and tears: extraterrestrial regolith
biocomposites with in vivo binders, Materials Today Bio (2021).
DOI: 10.1016/j.mtbio.2021.100136
Tags:
Space & Astrophysics