Recursion and unbounded loops are far too risky on their own, even ignoring the problems they cause for static analysis. The code that goes on NASA spacecraft is bombarded by cosmic rays on a daily basis, something a server sitting in a building at the bottom of the atmosphere doesn't have to worry about nearly as much. Even if the code is perfect, if a ray hits the right spot it's possible for it to flip a bit and then your perfect recursive function will do who knows what. [1]

They use error-correcting memory to combat this, but it's still better to be safe than sorry when your software controls a multimillion dollar space oasis with human beings inside who have no means of escape.

[1] http://www.statemaster.com/encyclopedia/Single_event-upset