The braking phase (BP) is comprised of two subarcs. The first subarc, known as the pre-quartic BP, starts at the perilune of the entry orbit and ends at the TCR point. The second subarc, represented as a quartic and known as the BP-quartic, begins at the TCR point and ends at the initial point of the AP. Connecting the pre-quartic BP with the entry orbit on the one side and with the BP-quartic on the other side was accomplished in the Apollo design using ground-based simulations in an iterative fashion. As stated before, our objective is to represent the pre-quartic BP analytically and to use continuity conditions to fit the pre-quartic BP into the descent trajectory.