Unlike the first stage, the second stage has just one gimballed engine, meaning it can counter pitch and yaw perturbations, but not roll perturbations.
Fins are effective for roll control, but at 50 miles up and above, the atmosphere is very thin, so after the first stage separates, the fins might not serve much purpose... or do they?
The dracos on the Dragon are in their element in those conditions, but do they fire with the second stage still attached?
Beside the fins and the dracos, there seems to be nothing else suited for roll control. The cold gas thrusters on the interstage are gone with the first stage, and there are none of these on the second stage or the Dragon module.
So my question is: how does the second stage of Falcon 9 control roll after the first stage and interstage separate and before the Dragon module separates? What means, specifically do they use? Thanks if you know and can share!