Landing on planet Planica An EU-funded survey on different aspects of living in space has been carried out in the Olympic Sports Centre Planica in Rateče, Slovenia. The work and findings have attracted the interest of scientific communities around the world. Space © Dorling Kindersley, Thinkstock Astronauts staying in a settlement on the Moon, serving as a springboard on their way to explore the solar system, will face hypoxic conditions along with reduced gravity. The Moon's gravity is smaller than that of Earth, and air pressure in suits, as well as housing units, will be lower than in the altitudes where most people live. Lower air pressure is accompanied by lower partial pressure of oxygen – that is, the Moon maintains a hypobaric hypoxic environment. The EU-funded PLANHAB (Planetary habitat simulation) project was initiated to study the combined effects of hypoxia and absence of gravity. To this end, 14 subjects lived for 21 days in rooms where air pressure and oxygen were the same as at an altitude of 4 000 m. During the whole stay, they remained inactive. The absence of gravity and inactivity has similar effects, causing gradual loss of muscle mass and body strength. Researchers monitored differences in the function of the cardiovascular and respiratory systems, bone density, digestion and metabolism. Experimental results were compared with data from bed-rest experiments conducted by the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA). PLANHAB research shed new light on physiological changes taking place in the human body when astronauts are exposed to hypobaric hypoxic conditions in space. Valuable insights were also gained in difficulties experienced by people with chronic obstructive pulmonary and cardiovascular diseases as well as overweight people. Project findings could be used to help patients with lung fibrosis, cystic fibrosis and congestive heart failure who also experience hypoxia. Results may also contribute to our understanding of obesity and weight loss as they highlight changes in metabolic function due to inactivity. Keywords Astronauts, Moon, hypobaric hypoxic, PLANHAB, absence of gravity, inactivity
