A FTL detection system using the properties of Subspace to detect vessels either in FTL flight or sub-light flight. Used for both early warning and navigation, the Abwehrans also use it for long-range, real-time targeting. Though, while it is a Faster Than Light, powerful detection system, it doesn't give an operator much detail. Not only does it only detect the mass of an object, but it can only detect objects above 60,000 kilograms (60 metric tons). While this isn't much of a problem for space craft, the Powered Armor of Yamatai are literally invisible to this detection.

Civilian models of Subspace Mass sensors are the weakest of its type. With shorter ranges due to power consumption restrictions, many civilian vessels are left with just enough detection range to avoid pirates.