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).