alt Hacker News>Otherwise this seems like a non-issue.
Except you forgot to mention an epic leak in Destiny just three years after it was attached to the ISS: "At its highest rate, the station was leaking about 5 pounds of air per day overboard." [0] Imagine that happening on the 4th year of American Mars mission.
Also, if you on American mission to Mars, it would be reasonable to worry about cooling system dying mid-flight requiring three spacewalks to fix it: "We'd lose cooling capability to half of the electronics on the U.S., European and Japanese part of the space station." [1]