usb hard drive sleep on airport ext base station

Hi, I am considering upgrading from airport express to one of the airport extreme base station models that support external usb drives for backup. The question I have is will I be able to set an option to have the "drive to sleep when possible"? Such as in osx system prefs?

I don't want to have my backup hard disk running all the time reducing its life span unnecessarily. If not I might just plug it in manually for my backups. thanks