Jeff Hopper
Mongoose
A tachyon is a theoretical particle that travels faster than light and backwards in time. The problem I have with their inclusion in Traveller is that if you can emit or control tachyons (even if it just from a cannon), then you have faster than light communications (even if it is as simple as morse code) and potentially time travel (which violates causality). This can be a problem in Traveller because you have just shot a hole in one of the iconic ideas for Traveller by making the speed of communications not be that of the fastest ship.