Once upon a time

"The first experiments with uncrewed ecosystems were performed by Russian scientists in the 1950s. This led to the crewed closed facility Bios-3 in 1965, a 315- cubic-metre habitat at the Institute of Biophysics in Krasnoyarsk, Siberia. Chlorella algae, which photosynthesise, were used to recycle air breathed by humans, absorbing carbon dioxide and replenishing it with oxygen. The algae were cultivated under artificial light. To achieve a balance of oxygen and carbon dioxide, one human needed 8 square metres floor space. Water and nutrients were stored in advance- these were recycled too. By the 1968, the system efficiency had reached 85% by recycling water. Bios-3 has conducted tests with two and three people un to six months.

NASA is also conducting Controlled Ecological Life Support Systems experiments. One of its core systems is the Biomass Production Chamber, a sealable steel chamber about 3.5 metres in diameter and 7.5 metres high with a plant-growing area of 20 square metres. In 1989, NASA completed BioHome, which integrated biogenerative components for recycling air, water and nutrients from human waste into a single habitat."

(From the New Scientist Print Edition, 03 April 1999)

The BBC2 TV show, Science Shack presented by Prof. Adam Hart-Davies, wished to answer the question 'Can you live underwater?' The team wished to build Prof. Adam Hart-Davis a self-sustaining underwater habitat, to discover whether it's possible to live permanently underwater. The AquaShack was constructed to demonstrate a number of the scientific principles involved in providing a self-sustained underwater habitat and to see if they could be simply applied using readily available materials.

The habitat consisted of two waste skips welded together with a door and weir arrangement to allow it to function as a diving bell. When it was fully submerged, and the minor leaks sealed, the habitat was occupied by Prof. Adam Hart-Davies and a photographer. The principle of the simple Sofnolime CO2 scrubber unit was described and the O2 and CO2 levels monitored. The makeshift absorber unit was demonstrated and worked well in controlling the CO2 expired by the occupants over the one-hour period of the experiment.

Unlike the AquaShack, The BioSUB Project will use an active bioregenerative system and not physical methods to create O2 from exhaled CO2. The BioSUB Project will also be designed to sustain a single occupant for a much longer period than the one-hour AquaShack experiment. Readily available materials, such as scrap metal, will be used for the construction of the habitat (pictured above).