Page:Project Longshot - Advanced Design Program Project Report.pdf/40

Rh chamber. The problem involved with using such a field (besides the obvious requirement for immense quantities of energy) is that only charged particles will be channeled out the nozzle. Although the extreme temperatures will instantly ionize all of the atoms and molecules, any neutrons produced in the fusion reaction will not be affected by the magnetic field. Instead they will irradiate the drive and the entire spacecraft over the 100 year transit, and reduce the drive efficiency. Since this is a highly undesirable result, a reaction which produces few to no neutrons is required (see appendix). He3 + H2 yields no neutrons (although realistically some of the deuterium will react with itself producing a limited number of neutrons in each implosion). The problem is not solved, however, since there is not enough He3 on our planet to fuel the spacecraft! Three methods of gaining the necessary He3 have been compared: mining the planet Jupiter; creating He3 through the bombardment of Lithium in nuclear accelerators; and capturing He3 from the Solar Wind. Another possibility is for a further technological breakthrough to enable using higher threshold-energy fusion reactions (higher than H,He) which use more abundant elements in a no-neutron reaction. None of the options seem very reasonable, and each should be explored and further developed to determine the best method for collecting the necessary fusionable material.

The pellet size, in order to obtain the proper mass flow through the nozzle, depends upon the pulse