Science and Exploration

Optimal Mass And Speed For Interstellar Flyby With Directed-energy Propulsion

By Keith Cowing
Press Release
June 29, 2022
Filed under ,
Optimal Mass And Speed For Interstellar Flyby With Directed-energy Propulsion
Illustration of the phases of a flyby mission for a probe propelled by directed energy from the launch site. The goal is to reliably recover the collected scientific data at the launch site.

The design of mission scenarios for the flyby investigation of nearby star systems by probes launched using directed energy is addressed.
Multiple probes are launched with a fixed launch infrastructure, and download of scientific data occurs following target encounter and data collection. Assuming the primary goal is to reliably recover a larger volume of collected scientific data with a smaller data latency (elapsed time from launch to complete recovery of the data), it is shown that there is an efficient frontier where volume cannot be increased for a given latency and latency cannot be reduced for a given volume.

For each probe launch, increasing the volume along this frontier is achieved by increasing the probe mass, which results in a reduced probe speed. Thus choosing the highest feasible probe speed generally does not achieve an efficient tradeoff of volume and latency. Along this frontier the total distance traveled to the completion of data download does not vary significantly, implying that the download time duration is approximately a fixed fraction of the launch-to-target transit time.

Due to longer propulsion duration when probe mass is increased, increasing data volume incurs a cost in the total launch energy expended, but with favorable economies of scale. An important characteristic of any probe technology is the scaling law that relates probe mass to transmit data rate, as this affects details of the efficient frontier.

David Messerschmitt, Philip Lubin, Ian Morrison

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Space Physics (
Cite as: arXiv:2206.13929 [astro-ph.IM] (or arXiv:2206.13929v1 [astro-ph.IM] for this version)
Submission history
From: David Messerschmitt
[v1] Mon, 27 Jun 2022 17:55:17 UTC (805 KB)

SpaceRef co-founder, Explorers Club Fellow, ex-NASA, Away Teams, Journalist, Space & Astrobiology, Lapsed climber.