Is this flight software?

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

Circular orbit

Velocity, period, energy and local g for a circular orbit at a given altitude.

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

v = √(μ/r) T = 2π √(a³/μ) ε = −μ/(2a)

Circular orbit velocity, period & energy

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.
JPL Horizons (NASA / JPL): Solar System ephemerides and body constants.

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