  While contact binary objects are common in the solar system, their formation
mechanism is unclear. In this work we examine several contact binaries and
calculate the necessary strength parameters that allow the two lobes to merge
without the smaller of the two being gravitationally destroyed by the larger.
We find a small but non-zero amount of cohesion or a large friction angle is
required for the smaller lobe to survive the merging process, consistent with
observations. This means it is possible for two previously separated rubble
piles to experience a collapse of their mutual orbit and form a contact binary.
The necessary strength required to survive this merger depends on the relative
size, shape, and density of the body, with prolate shapes requiring more
cohesion than oblate shapes.
