Vector angle

Angle between two 3D direction vectors: cone angle, boresight, sun aspect teaching.

SIDUS educational calculator. Category geometry. Tags: geometry, GNC, pointing, trigonometry. Pure SI. Not flight software.

Formula

cos θ = (a·b) / (|a||b|)

Angle between two vectors

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.