Radiation Effects from ISM and Cosmic Ray Particle Impacts on Relativistic Spacecraft

TL;DR

This paper examines the unique radiation environment faced by relativistic interstellar spacecraft due to interstellar medium impacts, analyzing radiation production, shielding effects, and implications for onboard device durability.

Contribution

It provides a detailed analysis of radiation effects from ISM and cosmic rays on relativistic spacecraft, highlighting the radiation environment and potential damage mechanisms.

Findings

Interstellar medium appears as a mono-energetic particle beam at relativistic speeds.

Impacts produce bremsstrahlung photons within spacecraft shielding.

Radiation doses are evaluated against onboard device tolerance levels.

Abstract

Relativistic spacecraft, like those proposed by the NASA Starlight program and the Breakthrough Starshot Initiative, will have to survive radiation production that is unique when compared to that experienced by conventional spacecraft. In a relativistic interstellar spacecraft's reference frame, the interstellar medium (ISM) will look like a nearly mono-energetic beam of charged particles which impinges upon the leading edge of the spacecraft. Upon impact, ISM protons and electrons will travel characteristic lengths through the spacecraft shield and come to a stop via electronic and nuclear stopping mechanisms. As a result, bremsstrahlung photons will be produced within the spacecraft shield. In this work, we discuss the interstellar environment and its implications for radiation damage on relativistic spacecraft. We also explore expected radiation doses in terms of on-board device radiation tolerance.