That's only a partial pressure of 20 kPa of oxygen. The Apollo capsule was supposed to be 20 kPa of pure oxygen, so providing the same partial pressure, but bec

That's only a partial pressure of 20 kPa of oxygen. The Apollo capsule was supposed to be 20 kPa of pure oxygen, so providing the same partial pressure, but because they were on the ground they couldn't do that or the spacecraft would be crushed by exterior atmospheric pressure (<tangent> https://www.youtube.com/watch?v=O4RLOo6bchU https://www.youtube.com/watch?v=O4RLOo6bchU </tangent>). So instead they pressurised it to one atmosphere. Of pure oxygen, thus providing a partial pressure of 110 kPa of oxygen...