Hill sphere

r_H approx a (m/(3M))^(1/3).

SIDUS educational calculator. Category planetary. Tags: geometry, mission-design, planetary. Pure SI. Not flight software.

Formula

r_H ≈ a (m/(3M))^{1/3}

Hill sphere radius

Primary sources

• Fundamentals of Astrodynamics and Applications (David A. Vallado): Standard reference for two-body, Lambert, maneuvers, and J2. Equations implemented independently in SIDUS.
• Orbital Mechanics for Engineering Students (Howard D. Curtis): Textbook derivations for Hohmann, vis-viva, rocket equation, elements.

How do AI agents use this tool?

Read /llms.txt or call https://sidus.tools/api/mcp. Open the interactive page for live SI inputs.