If you need to start a process, you can use the Start-Process.
However, it become a child process of your dashboard process.
When using IIS, the application pool that run your dashboard will recycle itself each x minutes, which will close the process opened that way.
That being said, a process created using the method below will be created not as a child process of your instance and remain unaffected by UD shutting down.
Invoke-WmiMethod -Class Win32_Process -Name Create -ArgumentList 'MyExternalProcess.exe'