There's also Passive Magnetic Attitude Control System (PMACS) that uses magnets, and does away with motors and reaction wheels. I guess PMACS is good enough for

There's also Passive Magnetic Attitude Control System (PMACS) that uses magnets, and does away with motors and reaction wheels. I guess PMACS is good enough for most of the nano/pico/femto satellites. It was recently used in an Indian student satellite "Swayam"[0]. [0] http://www.coep.org.in/csat/subsystems/acs/ http://www.coep.org.in/csat/subsystems/acs/