I'm personally not a fan of antimatter propulsion at this time as there's no
safeguarding technology for when the launch or a component during flight
fails. The only way to encapsulate antimatter at this time is through
magnetic containment, which needs power and a complex control system. If
these fail during launch or at any time during the flight the result will be
an explosion which dwarfs that of a hydrogen bomb.



30 milligrams of antimatter won't make that big of an explosion. Certainly not
enough to dwarf a hydrogen bomb. What it can do is produce high energy
densities that could be used to initiate hydrogen fusion on a small scale. Most
of the energy that propells the ship would come from hydrogen fusion.
Antimatter will never be completely safe.

Tom