Buck,

Matthew Draper, 18 year old grade-school student, is hardly a credible source for a "10 year" atmosphere loss comment.

Mars' gravity is sufficient to retain an Earth-like mix of N2/O2 against thermal escape for gigayears. Heck the Moon could hang on to an Earth-like atmosphere for over a billion if thermal escape was the only issue.

However solar wind interactions cause nitrogen to escape over millions of years. A magnetic field and deeper gravity would mitigate its loss. But it's not an issue for CO2 or O2 in the current solar wind environment. In the early days with higher solar wind perhaps ~ 90% of the atmosphere was eroded when Mars' field died away.

Adam