Adamantium Fusion Tube

A fusion rocket reaction chamber made from Hexamite adamantium. Due to adamantium's nigh-indestructable properties, it can withstand the heat and radiation of any fusion reaction occurring inside, whereas ordinary engines must rely on magnetic nozzles and heat shields. This means ships using adamantium fusion tubes can have their engines built much more compact than conventional vessels, enabling such things as torchship belly-landers designed like large aircraft instead of rocketlike towers, with the engine(s) on the underside.

Such amazing engine technology is not without its downsides, however. Since the material cannot be produced by Stellar Compact civilization and must be scavenged from Hexamite space, adamantium fusion tubes are quite expensive, adding a great deal of cost to a spaceframe. Nor do they completely alleviate radiation concerns; backscatter still occurs off the drive plume when using neutron-producing fusion reaction cycles such as deuterium-deuterium.