Breathing pure O
2 in space applications, such as in some modern space suits, or in early spacecraft such as Apollo, causes no damage due to the low total pressures used. In the case of spacesuits, the O
2 partial pressure in the breathing gas is, in general, about 30 kPa (1.4 times normal), and the resulting O
2 partial pressure in the astronaut's arterial blood is only marginally more than normal sea-level O
2 partial pressure (for more information on this, see space suit and arterial blood gas).
Why is breathing oxygen in space craft not dangerous to health?
low total pressures low total pressures used low total pressures low total pressures the low total pressures used