Is this flight software?

No. SIDUS models are educational reimplementations. Cross-check before any flight decision.

Vis-viva equation

Orbital speed at radius r on an ellipse of semi-major axis a.

SIDUS educational calculator. Category orbital. Tags: orbital, vis-viva. Pure SI. Not flight software.

v = √[ μ (2/r − 1/a) ]

Speed anywhere on the conic

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.
NASA Glenn Research Center: Beginner’s Guide to Aeronautics (NASA GRC): Ideal rocket equation, specific impulse, thrust equation, dynamic pressure education pages.

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