Project Icarus: The Pegasus Interstellar Spacecraft Propulsion Power Cycle

K. F. Long

jbis-078-10-0330

DOI https://doi.org/10.59332/jbis-078-10-0330

The use of fusion reactions within a propulsion engine involves enormous amounts of energy and power. In the design of any vehicle concept, it is important to attempt to quantify the gains and losses from the system to arrive at a reasonable estimate for the jet power and the jet efficiency as descriptive metrics for the engine performance. In this paper the power cycle is discussed for the Pegasus interstellar rendezvous spacecraft under the assumptions of minimal energy loss. This is described using a method developed by this author known as power cycle line maps. It is concluded that whilst the Daedalus flyby probe was able to assert a jet efficiency of ~91%, such an assumption is only feasible when one assumes no energy losses such as due to neutrons and x-rays. Instead, we adopt a more realistic model and do assume associated energy losses, so that the jet efficiency for Pegasus is determined to be of order ~85%. This implies that some degree of radiation shielding would be required to protect the spacecraft. It also comes with the implications of a requirement for highly efficient lasers and radiators to maintain a practical spacecraft mass to complete the mission. This paper is a final contribution to Project Icarus.

Keywords: Project Daedalus, Project Icarus, Pegasus