The first explosion is the smaller second stage igniting. The second, bigger explosion is the first stage exploding. The first stage has most of the mass of the

The first explosion is the smaller second stage igniting. The second, bigger explosion is the first stage exploding. The first stage has most of the mass of the rocket in the form of propellant and is what SpaceX lands on the barge after it separates from the second stage. The second stage is smaller and lighter, and puts the satellite into low earth orbit, or into its transfer orbit in the case of higher orbits (eg geostationary orbit). The 'nose' falling is payload and its protective fairing. The idea of a fairing is to protect the the satellite from aerodynamic, heat and acoustic stress. It explodes because the satellite has propellant in it - certainly for its rcs system for attitude adjustment and station keeping, and it might have a main engine to help it reach orbit. http://www.spacex.com/falcon9 http://www.spacex.com/falcon9 http://www.spacex.com/news/2013/04/12/fairing http://www.spacex.com/news/2013/04/12/fairing