Project Icarus: An Assessment of the Particle Bombardment Problem on Interstellar Spacecraft

Kelvin F. Long

jbis-078-06-0216

DOI https://doi.org/10.59332/jbis-078-06-0216

In this paper we give an assessment of the particle bombardment problem for interstellar spacecraft from dust in the interstellar medium. We examine the minimum requirements for a set of fusion spacecraft designs under Project Icarus, a successor to the 1970s Project Daedalus study. It is found that whilst protons and electrons may give rise to heating of the spacecraft, the erosion of any shield material is dominated by dust grains. The interstellar dust grains are assumed to have a matter density of 2.57 × 10-17 gcm-3 and the largest may be as large as 0.1 μm or 5 ng, assuming a typical solid density of 3 gcm-3. Maximum erosion rates are predicted to be of order 3 × 10-5 gs-1 for the largest grains. Calculations suggest a shielding mass for Project Icarus of around 1 tonne with a minimum thickness of 1 mm, will be sufficient to protect the spacecraft against dust impacts during the cruise phase of the flight. However, a larger shield is recommended to account for impacts occurring during entry into the stellar system prior to planetary encounters occurring, and to account for high energy charged particle penetration. This paper is a final contribution to the Project Icarus Study Group.

Keywords: Interstellar Studies, Fusion Propulsion, Project Daedalus, Project Icarus