DCOMCNFG Settings with Powershell?

In a Windows GUI, I would do this;
DCOMCNFG.EXE
      Computers / My Computer / Properties / COM Security
            Launch and Activate Permissions
                         … add [username] ..... with full privileges

I'd like to put this in a script.  The only things I've found seem to be more trouble than they're worth and I've been tempted to simply continue to do this manually from the GUI.  
But, if there's something I could put into a script that isn't too convolved, then I'd very much appreciate learning what that might be.