When it came to the Re-Entry System ( RES ) , the US Navy was using the Mark 2 Mod 0 RES .
When it had a new version , the Mark 2 Mod 1 under development .
When it came to the Re-Entry System ( RES ) , the US Navy was using the Mark 2 Mod 0 RES , but had a new version , the Mark 2 Mod 1 under development .