Space Matrix Restoration Coil

The Space Matrix Restoration Coil refers to part of a starship's Warp Drive. (Star Trek: The Motion Picture)

While the exact function of this component is unknown, it can be surmised that the device in some way alters the state of particles that interact with the warp coils. It is generally believed that the device in some way keeps the Coils in phase with the normal universe and prevent them from slipping into subspace as a result of the massive energy fields that they generate.

The Coil could very well be a single item, although it is more likely that there are a pair of them, one in each of the Warp Nacelles. This would allow for redundancy, and also makes sense considering that both nacelles contain Warp Coils.

The exact nature of the process that the coils create is unknown but it can be speculated that it has something to do with the Phase variance of the coil materials. This would mean that the Warp Coils could potentiall phase out of our normal reality and thus could cause subspace rifts if these devices were to fail. That would make them a very vital component to the Warp Drive.