Yes, I think I am getting way too excited about what I've found so far. I need to real it in a bit and double check all my numbers. As exciting as it is to find a planet I think would be safe, I'm sure I'd be the guy in the movie that dies first after stepping out of the hatch without a helmet on.
So far, nearly 100 planets have been submitted. Around half of those were totally un-breathable. More than a third where tolerable for up to only 1 hour. A few were unknown since not all gasses where shown, but they would have been in either of those categories.
Only three (3) planets show signs of being truly breathable for more than an hour. However, all of those show indications of having too rich of an Oxygen mix in their thinner atmospheres than we are used to. The inspired O2 is too high if over 50% to 60%.
In no particular order, take your pick, these planets will sustain you without protection, for a few days most likely. That is if the cold isn't too much for you to take. (Cool planets are survivable, Cold planets are simply too cold IMHO).
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RS 0-8-3894743-1646-33-8-7338743-802 3
Cool Desert with Organic unicellular terrestrial life
-70°C .229atm .335g all tolerable limits
O2 86% .197atm high inspired rate
CO2 14% .0321atm adaptable
SO2 4.28ppm 9.81*10^-7atm smell detectable
H2S 1.33ppm 3.05*10^-7atm smell detectable
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RS 5278-14-8-14274230-682 4
Cold Desert with Organic unicellular terrestrial life
-110°C .434atm .93g too cold to breathe
O2 88.9% .386atm high inspired rate & pressure
CO2 11% .0479atm dangerous
H2S 5.71ppm 2.48*10^-6atm nausea
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RS 5281-63-5-29597-72 6.5
Cold Desert Moon with Organic unicellular terrestrial life
-103°C .292atm .648g too cold to breathe
O2 77.1% .225atm high inspired rate
CO2 22.5% .0658atm just over an hour allowed
H2S 2.83ppm 8.26*10^-7atm smell detectable