An apparatus (24) for bursting pipe is preferably adapted to receive energy from a drill string (14). The apparatus has a plurality of spherical pipe-bursting members (70) driven by movement of the drill string to burst an in situ pipe. In a preferred embodiment a single-member drill string is used to drive operation of a plurality of spherical pipe-bursting members disposed about a frame (64) of the apparatus. In other preferred embodiments, rotation of the inner member of s dual-member drill string is used to drive operation of the spherical pipe-bursting members. Spherical pipe-bursting members increase the efficiency of pipe-bursting operations by utilizing rotational energy generated by the movement of the members.