Ada is just too restrictive and slow for complex distributed systems in my opinion and if you think about it with these sort of systems there are going to be instances when you need to either do something in assembler or you need a really efficient compiler which from memory the Ada one was pretty rubbish. Ada 95 was god awful and from memory Ada 83 didn't support threading.
I don't really see a barrier to using C++ for these sorts of projects they just need to be engineered as in using software engineering processes. Looser commercial development practices while great for cranking stuff out or 'prototype' code out quickly won't really cut it, which is why I assume the software component of the project is so long and has been marked as one of the biggest risks to be managed as there is probably a very onerous and long winded design, code, review, test, integration cycle going on.
Last edited by eaglemmoomin; 17th Dec 2012 at 12:12.