Is this flight software?

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

J2 nodal precession

RAAN drift rate due to Earth oblateness (J2).

SIDUS educational calculator. Category satellite. Tags: LEO, mission-design, orbital, satellite. Pure SI. Not flight software.

Ω̇ = −³⁄₂ n J₂ (R/p)² cos i

Secular nodal precession

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.
CelesTrak (CelesTrak): TLE sets, NORAD element documentation, and Vallado software companion hosting.

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