The Emthruster: Thrust without reaction?

[stevebowers]

Man-rated beamed core ships were not successfully built until 1120 AT, during the First Federation. This allowed the First Fed to expand at a faster rate than the pre-Nanoswarm colony effort.
http://www.orionsarm.com/eg-article/493d299bc818c

In many ways tech development in OA is quite conservative; with technologies like antimatter propulsion and interstellar travel, there are bound to be very long development times and unexpected difficulties.