Low Pressure Atmosphere
A Low Pressure Atmosphere is a type of atmosphere known for possessing thinner and less thick gaseous components.
- While the definitions of a low pressure and the thinner atmospheres overlap, there can be considerable differences as well.
Low pressure atmospheres will have a variety of effects on life, both native and alien:
- Air temperature will be lower and the atmosphere will retain less heat; it will also have extreme differences in temperature between day and night. The air in a thin atmosphere will be drier than that of a Standard Atmosphere, forcing both humans and native wildlife to drink more water.
- A further drawback will be the lack of protection the atmosphere provides from the effects of solar radiation. In addition, with fewer air molecules to push against, native animal life will find it difficult to get into the air. There will be few, if any, flying creatures on these worlds.
- Finally, with less oxygen available, humans will struggle physically, and this struggle will be shared by any combustion-engined vehicles. Railway trains on the high altitude Andes mountains on Terra struggle to cope with some of the serious inclines on the track because the power isn't there - compressors will need to be fitted to engines in order to supply enough air to keep them running. On mid-tech planets (TL-5 to 8) with thin atmospheres, electrical motors might take the place of more inefficient combustion-engined vehicles and power sources. 
History & Background (Dossier)
One of the advantages of living on a low pressure or vacuum world is easier access to space. Planetary spaceports on low pressure worlds can often provide construction shipyards at a drastically reduced cost, often competitive with orbital shipyards.
Geneticists often studied the life indigenous to such worlds looking for higher efficiency respiration systems to build into future cybernetics and technological augments.