Can PLSS in atmosphere use enriched oxygen?

Question

Does Mars space suit have to be pressurized? makes it pretty clear the atmospheric pressure on Mars is a miniscule fraction of Earth's own.

In it's turn Wikipedia writes to say that the atmosphere of Mars is mostly Carbon Dioxide. This is at odds with Earth orbit (where the space-walks happen). It is also significantly different from the vacuum experienced by the Apollo astronauts on Luna.

The PLSS together with the EMU form a closed system relative to the Martian atmosphere, is there any reason to change the breathing mixture in the PLSS for use in atmosphere?

Answer 1

The oxygen mixture depends on the pressure. The pressure limits on a space suit are basically limited to the fact that an inflated space suit tends to become stiff, much as a balloon that is blown up is stiff. The pressure on Mars isn't different enough where there will be a significant pressure difference, thus, if a current generation space suit were used on Mars, the pressure/ oxygen mixture would most likely remain nearly identical.