After liftoff and separation from stage one of the Falcon 9 rocket, the SpaceX Dragon capsule must successfully perform several functions to get ready to dock with the ISS. A few minutes after the Dragon separates from the second stage of the Falcon, at about T+12:00, the sequence to activate the solar arrays starts. Try to recall the COTS 2/3 mission webcast, there was cheering from SpaceX employees after the solar arrays deployed. While SpaceX employees have a right to cheer about every aspect of the Falcon and Dragon, the solar arrays are unique. Most spacecraft similar to Dragon only use battery power.