You don't know what kind of tools they've developed internally and Ada/Spark is far from the end-all be-all of high assurance programming. High assurance comes

You don't know what kind of tools they've developed internally and Ada/Spark is far from the end-all be-all of high assurance programming. High assurance comes from the overall systems design and testing, not the software itself. Afterall, radiation can cause any piece of software, including those written in Ada, to completely skip instructions.