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 path loss (Friis / ITU-style FSPL) (ITU / standard radio engineering): L_fs = 20 log10(d_km) + 20 log10(f_MHz) + 32.44 dB form used in educational link budgets.
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.