18 | New Scientist | 6 March 2021
News
BIOLOGICAL life support systems,
or biospheres, could now recycle
enough oxygen, water and food
to keep people alive for years.
Two groups of four people lived
in a sealed environment in China
called Yuegong-1, or Lunar Palace 1,
for a total of a year, with one
group spending a record-setting
200 days in the facility without
needing any outside materials,
and they could have gone longer.
The project aims to help China
establish bases on the moon.
Details of the experiment,
which ended in May 2018, were
revealed in a study posted online.
The researchers say volunteers got
98 per cent of the materials they
needed to survive from recycling,
with just 2 per cent coming from
the outside, including seeds, toilet
tissue and cleaning materials.
These are the best results
achieved so far. “Now we are
reaching a level of closure that
is good,” says Christophe Lasseur,
who leads the European Space
Agency’s effort to develop
regenerative life support systems,
called the MELiSSA Project. Such
systems can’t yet sustain people
indefinitely, he says, but they
can now do it “for a long period”.
“If they have accomplished
what they claim to have
accomplished, that would be
a huge step forward,” says Rob
Suters at Semilla Ipstar, a Dutch
company that commercialises
MELiSSA technology.
There have been many efforts
to create habitats that sustain
people, starting with Russia’s BIOS
experiments from the 1960s to the
1980s. The Biosphere 2 facility in
Arizona is the most famous. One
of the crewed experiments done
there in the 1990s lasted two years,
but extra food and oxygen had to
be supplied, so it is regarded as a
failure. Japan also did a series of
crewed experiments in the 2000s.Lunar Palace 1 was built in 2013,
with the first crewed experiment
in 2014. The facility consists of a
small living cabin linked to two
larger cabins filled with shelves of
plants growing under LED lights.
In the latest experiments,
all the oxygen generation and
carbon dioxide removal was done
by the plants, which included
wheat, potatoes, tomatoes, carrots,
cucumbers and strawberries.
There were some fluctuations
when the crews swapped but gas
levels remained within safe limits.
Waste water was treated in a
bioreactor and sterilised with
UV light before being used for
irrigation. Drinking water was
obtained by condensation and
also sterilised. Some plant waste
was used to grow mushrooms
and then fed to mealworms, which
were made into a kind of protein-
rich bread. Faeces were mixed
with plant waste and fermented
to produce CO 2 for growing plants.Some residues left after processing
urine and faeces were stored. All
crew members stayed physically
and mentally healthy, the study
says (bioRxiv, doi.org/ghtbdd).
“A good measure of these
systems is how many square
metres do you need to support
one crew member,” says Oscar
Monje at NASA’s Kennedy Space
Center in Florida. In Lunar Palace 1,
there were 40 square metres of
growing area per crew member,
compared with 75 square metresin the Japanese experiments,
says Monje. “That’s pretty
good, and matches what NASA
predicted from its crop testing.”
The main aim of the research
is to create life support systems
for space exploration. “It would
make long-term space travel much
more feasible, as you would not
need to bring so much mass,” says
Suters. But supporting people on,say, a lunar base remains an
immense challenge. For starters,
a moon base would have to be
underground to protect it from
radiation, says Monje. Then it has
to be powered. “If you want to do
it with solar collectors, it would
be a huge area so you probably
need a nuclear reactor,” he says.
The moon is especially
challenging because a lunar day
lasts an Earth month, says Lasseur,
giving it a long period of extreme
cold and dark. And a system that
works on Earth won’t necessarily
work in space. The European
Space Agency is taking a different
approach, focusing on testing small
components on space flights rather
than trying to build a complete
system on Earth. But it has set up a
“space greenhouse” in Antarctica.
NASA, meanwhile, has been
studying how to grow plants
in space, installing the Advanced
Plant Habitat on the International
Space Station in 2018. However,
the aim of this work is just to
supplement the diet of astronauts
on long missions with fresh food
rather than for life support. ❚Michael Le PageCH
INADAILY/REUTER
S/PA^ IMAGESSpace explorationChina’s self-sustaining biosphere
Crew lived a record 200 days on recycled oxygen and water, growing their own food
LED lights kept plants
alive inside China’s
Lunar Palace 1 biosphere98%
Amount of key materials biosphere
inhabitants got from recycling