Is this flight software?

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

RF link budget

One-way free-space link: EIRP, FSPL, P_r, C/N₀ and margin (comms / constellation).

SIDUS educational calculator. Category satellite. Tags: comms, constellation, operations, RF, satellite. Pure SI. Not flight software.

L_fs = 20 log d_km + 20 log f_MHz + 32.44

Free-space RF link margin

AeroVia Aerospace Tools (AeroVia (public calculators)): Public catalog of ISA, dynamic pressure, launch azimuth, RF link, SSO-class tools (domain demand reference).
Free-space attenuation (ITU-R P.525-5) (International Telecommunication Union Radiocommunication Sector (ITU-R)): ITU-R P.525-5 Eqs. (5)–(6): L_bf = 20 log10(4πd/λ); practical form uses d in km and f in MHz with a 32.4 dB constant. SIDUS uses 32.44 dB as an approximation of the same Friis relation.
Space Mission Engineering: The New SMAD (Wertz, Everett, Puschell (eds.)): Mission engineering handbook: RF links, constellations, and ops framing.

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