 At first-stage burnout, explosive bolts fired and springs separated the instrument section from the first-stage tankage.The instrument section and the spinning tub were slowly tipped to a horizontal position by means of four air jets located at the base of the instrument section.When the apex of the vertical flight occurred after a coasting flight of about 247 seconds, a radio signal from the ground ignited the eleven-rocket cluster of the second stage, separating the tub from the instrument section.