My guess? There have been a few high profile security CVEs lately and the "why are we still using C" crowd is louder than usual. Ada's a viable alternative for performant system code, and it's kind of the underdog to Rust.
Ada is memory safe if you just work with the stack or avoid Unchecked_Deallocation. Since functions can allocate and return entire arrays and other data structures completely on the stack, you don't need to mess with the heap that often (and when you do, you can also define your own memory pools).
If you have to use dynamic allocation, you could also use the built in container libraries or controlled types for additional safety.
Though if you want the kind of memory safety that Rust has, there's always SPARK (a subset of Ada).