----------- HULL SYSTEMS and PROBLEMS-----------------
++With the gas and dust in interstellar space.
++Tenuous gas with a density on the order of one nuclear particle per cubic centimeter.
++30000 km^3 of interstellar space would barely fill a thimble.
++Interstellar gas also creates a radiation hazard.
++This ice could form the outer layers of a ship,
  active electrostatic or EM shields ,
++Traveling at relativistic velocities, collisions w/ micrometeoroids,
  little craters are gouged n the hull,
  erode away passive shields several meters thick.
++High intensity beam of short wave radiation projected in front
++Ionized plasma could then be shunted out of the way by active radiation
++First phase, heavy freighters,
  robotic and will carry everything needed to colonize and terraform a new star