Project Icarus: A Review of Local Interstellar Medium Properties of Relevance for Space Missions to the Nearest Stars

TL;DR

This review summarizes the properties of the local interstellar medium within 15 light-years of the Sun, emphasizing their importance for planning future interstellar space missions at speeds of 0.1c or higher.

Contribution

It provides a comprehensive overview of local interstellar medium properties relevant for designing interstellar probes and mission planning, highlighting the need for conservative assumptions.

Findings

Local interstellar medium density estimates vary widely.

Design considerations for interstellar probes depend on assumed medium density.

Recommendations for parameter values in mission planning.

Abstract

I review those properties of the interstellar medium within 15 light-years of the Sun which will be relevant for the planning of future rapid ($v /ge 0.1c$) interstellar space missions to the nearest stars. As the detailed properties of the local interstellar medium (LISM) may only become apparent after interstellar probes have been able to make in situ measurements, the first such probes will have to be designed conservatively with respect to what can be learned about the LISM from the immediate environment of the Solar System. It follows that studies of interstellar vehicles should assume the lowest plausible density when considering braking devices which rely on transferring momentum from the vehicle to the surrounding medium, but the highest plausible densities when considering possible damage caused by impact of the vehicle with interstellar material. Some suggestions for working values of these parameters are provided. This paper is a submission of the Project Icarus Study Group.