# The Interplanetary Habitable Zone

**Authors:** Caleb Scharf  
**arXiv:** [2602.13404](https://arxiv.org/abs/2602.13404)  
**Date:** 2026-02-13  
**Summary page:** https://www.summarizepaper.com/en/paper/2602.13404v1/

## Key points

- Caleb Scharf introduces the concept of Interplanetary Habitable Zone (IHZ) for space-faring interplanetary species
- Study is agnostic to specific operational details but makes assumptions about energy harvesting, orbital mobility costs, radiation risks, and resource requirements
- Multi-modal figure of merit developed to evaluate IHZ
- Agent-based model used to simulate dispersal of interplanetary life in a planetary system and characterize IHZ
- Resource weightings between planetary bodies influence migration patterns from Earth to Moon, Mars, and asteroid belt in our solar system
- Comparison with Trappist-1 system identifies critical sensitivities in balancing resource availability with risk or cost factors shaping IHZ
- Results suggest advantages for space-faring species in our solar system compared to Trappist-1 system
- Modeling approach provides insights into potential habitats for interplanetary life and implications for emerging space economies within our solar system

## Summary

In "The Interplanetary Habitable Zone," Caleb Scharf from NASA Ames Research Center introduces and explores the concept of a system-wide measure of habitability for space-faring interplanetary species. The study is agnostic to the specific operational details of interplanetary life, such as technology or organism traits unknown to us, but makes assumptions about energy harvesting, orbital mobility costs, radiation risks, and resource requirements. A multi-modal figure of merit is developed to evaluate an interplanetary habitable zone (IHZ), and an agent-based model is used to simulate the dispersal of interplanetary life in a planetary system and characterize the IHZ. The research highlights how resource weightings between planetary bodies in our solar system influence migration patterns from Earth to the Moon, Mars, and the asteroid belt. By comparing these findings with the Trappist-1 exoplanetary system, critical sensitivities are identified in balancing resource availability with risk or cost factors like radiation risks and orbital Delta-v costs that shape an IHZ. Results suggest that our solar system may offer significant advantages for space-faring species compared to systems like Trappist-1. This modeling approach not only sheds light on potential habitats for interplanetary life but also has implications for emerging space economies within our own solar system. The study provides valuable insights into the sustainability and viability of life beyond Earth, offering a framework for understanding habitability on a system-wide scale.