Turning Off/On SATA disk

Hello guys (and gals), does anybody know if there is a (safe) way to force a SATA disk to enter the lowest power consumption mode (causing it to shut down) while having the possibility to reset it when needed? I'm looking for something similar to the options provided by the hdparm utility in the case of IDE disks. I plan to perform regular backups on two big SATA disks in an automated way, turning them on just to perform an incremental backup and then turning them off again. This may be a crazy idea, do you think it would be safer to just force the disks to spin down/up or even keeping them in full power mode? - José Luis