Wow, thanks so much for reporting! This is an awesome report, congratulations! 
I have confirmed the 
character is indeed the cause of your issue, but it’s more serious than it appears. Even if you manage to start a mission, your progress will not be saved.
Technical: This bug affects all Steam names which start with a Unicode codepoint that requires surrogate pairs to be represented in UTF-16 (that is, a codepoint that belongs in the supplementary planes, range U+10000…U+10FFFF).
I will issue fixes for all Steam games as soon as possible.
Fixed… soon 
Bug