I think people generally assume systems programming requires low latency and that using a GC implies high latency. That's mostly, but not strictly, true. If you're writing a web server, as opposed to a missile guidance system, the occasional GC pause is probably not a dealbreaker.
Here's an article from IBM on their work on real-time Java, where they develop a GC that can provide a bound on latency, and on the amount of time spent doing GC: http://www.ibm.com/developerworks/java/library/j-rtj4/
Based on that, I don't think I'd rule out the feasibility of doing a missile guidance system in a GC language.
