Space living: The Luna Gaia design would reduce the need for costly supply missions to ferry food, air and water backwards and forwards from colonies on the Moon and Mars.

Credit: NASA

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SYDNEY: Australian-led scientists have designed a new space habitat that might one day allow astronauts on the Moon or Mars to be 90 to 95 per cent self-sufficient.

The development of such as system could save billions of dollars in shuttle trips to re-supply lunar or space colonies and brings closer the vision of a human habitat on Mars.

The technology could also have applications on Earth to develop more sustainable farming techniques and improve recycling processes.

Luna Gaia

Some systems to recycle water and air have already been developed and rudimentary versions are presently used in the International Space Station (ISS). However, the proposed new lunar habitat "combines our existing knowledge" of physical, chemical and biological processes to provide an "overall picture of how a minibiosphere would work," said James Chartres aerospace engineer at the University of Adelaide in South Australia. He gave a talk detailing the design at the Australian Space Science Conference held in Sydney last month.

The project is in some ways similar to the failed Biosphere 2 experiment, built in Arizona, U.S., in the late 1980s. Over an area of 12,000 m², Biosphere housed a closed ecological system, incorporating a mini 'ocean' with coral reefs, as well as a grassland, desert, mangrove, rainforest and agricultural areas. Eight people survived in the habitat for two years, but a lack of food and low levels of oxygen hampered the experiment. Chartres detailed plans for a smaller, space-bound concept, dubbed Luna Gaia.

Devised by an international team of 30 space scientists, Luna Gaia would be a 'closed-loop' environment, meaning that almost all material within the system is recycled with very little need for input from outside sources. The current design caters for a team of 12 astronauts under isolation for up to three years.

Currently, recycling that occurs on the ISS is driven by chemical reactions. A big challenge to developing a totally integrated system is developing a biological recycling system said Chartres. He argues that for efficient recycling, microorganisms are required.

Crops in space

His team devised a new system that takes into account all details of living in an enclosed system in space, even down to the materials that supplies are packed in.

The Luna Gaia concept integrates technologies such as the Closed Equilibrated Biological Aquatic System (CEBAS), an enclosed aquarium designed by the German Aerospace Centre and the Micro-Ecological Life Support System Alternative (MELIiSSA) developed by the European Space Agency. MELIiSSA uses microbes to purify water, recycle carbon dioxide and derive edible material from waste products.

Algae – which generates oxygen from carbon dioxide via photosynthesis, and doesn't require pollinating – is the key to the proposed design.

The food required for astronauts would come from a mixture of tending small crops and from pre-packed supplies. Such crops would include peanuts, lettuce, tomatoes, carrots and wheat. In addition, certain types of algae, such as Spirulina or Chlorella would provide other vitamins, minerals and trace elements.

The diet would be largely vegetarian, said Chartres, but protein could potentially come from small-scale farming of fast-growing fish such tilapia.

A lunar base is unlikely to ever be 100 per cent self-sufficient, said Chartres, because no atmosphere is completely safe from leaks and it could not provide humans with all the nutrients that they need to survive.

Moreover, astronauts need the occasional break to the routine of standard food, so the odd "luxury item such as fruit salad, spices or chocolate," would ward off any doldrums, he said.

Significant hurdles

Pathogens introduced to the system by plants, as well as difficulties of pollination for crops still pose significant hurdles to the design. In addition, as much as 20 m² of plants would be required to feed a single astronaut.

The proposed system, is unlikely to be up and running any time soon. Chartres estimates it will be another 20 to 30 years before the funding for the set-up and the practicality of providing the space for plant growth in a spacecraft is realised.

Mark Kliss a bioengineer with the NASA Space Biosciences Division in Moffett Field, California, said he found the project interesting.

"Certain subsystems could be, and in some cases are currently being used on Earth to provide improved water reclamation techniques, better contamination control methods, superior solid waste management technologies, advanced crop productivity techniques, as well as application to carbon credit and green building technologies," said Kliss of the wider applications.

He added that any knowledge gained from attempts to develop and operate "relatively closed, regenerable life support systems" is useful because it helps us understand how to utilise limited resources as efficiently as possible.

"This is an issue that is not only important for future long duration human space missions, but for humans on Earth as well," he said.