Hacker News Reader

There's less oxygen available with a face mask. It should also be noted that NASA has an inflatable module that's being tested against space, but I don't know if there's any similarity here.

View on HN

There is no less oxygen available with a face mask. The concern with full face masks is that they contain more dead space which can lead to dangerous CO2 accumulation. Divers who use full face masks or hard helmets often turn on at least a little free flow gas to supplement the demand valve regulator and keep their CO2 levels down.

Full face diving masks are designed to have an air flow that helps minimize CO2 buildup[0]. The greater concern is that they might leak due to not fitting properly, and/or the user might panic and pull the mask off while underwater.

[0] http://www.opstechnologies.com/products/scuba/full-face.html

Reply on news.ycombinator.com