Observer

Overview

Serenity UAV is a fully functional electric ducted fan (EDF) tilt-rotor aircraft engineered as an actual physical build of the Firefly-class transport Serenity (Joss Whedon, 2002) — every component here is fabricated or procured, not conceptual. A two-part SLS-printed hull (one-piece forward head+cargo section and one-piece aft middle+rear section) carries two tilting EDF nacelles, a belly cargo bay with powered winch and clamshell doors, and an 8-node cooperative avionics architecture with PACE (Primary/Alternate/Contingency/Emergency) failover across every flight-critical function.

The design is held to the same rigor as a certifiable aircraft: real mass/CG/load budgets (no "TBD" specs), FAA/FCC/NIST/IEC standards vetting on every design decision with any effect beyond cosmetics, redundant power and control paths throughout, and a zero-trust security model — every onboard message is signed, authenticated, and logged to hardware-enforced non-executable storage — engineered to keep operating correctly inside a 500 W/m² RF field. Avionics, comms, and software are built for reuse across other UAV/UGV/USV platforms, not just this airframe. See AGENTS.md for the full authoritative project policy that governs every design decision in this repository.

Project Status (2026-11-03)

Rev U, design and PCB layout. Nothing is fabricated or assembled; the physical build has not started. The path to first flight is in docs/FIRST_FLIGHT_READINESS.md; open work is in TODO.md, generated from the full record in WBS.md.

Subsystems

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Table of Contents

• Project Status
• Authoritative Project Instructions
• References
• License
• Attribution
  • Component License Map
  • What This License Covers
  • Patent Notice
  • Forensic Evidence Integrity Note

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Authoritative Project Instructions

The canonical workspace instructions and design policy are maintained in AGENTS.md. All contributors and automated tools (including AI assistants) shall follow the requirements and standards documented there (coding style, fabrication specs, licensing, and attribution). CLAUDE.md is a one-line pointer to the same file, kept for tooling that looks for that name.

The Nominal Mission Profile and Specifications above are the current design baseline. Full engineering detail for each subsystem lives in that subsystem's own README/doc — see the link on each card in Subsystems above. The narrative that used to live directly in this file (full Airframe/Powerplant/Avionics/Cargo Handling write-ups) is preserved verbatim, for historical reference, in archives/root-readme-deep-dive-2026-08-03/.

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References

• Design conversation: claude.ai/share/a1e3900e-d2bf-4690-ba63-25178e7de666
• Latest design revision BOM: current-specification/bom_revU.json (Rev U, 2026-11-03)

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License

Licensed by Steve Griffing, PE(CSE), CISSP-ISSEP, CPP, according to what each file produces:

• Hardware — and any code that defines, creates or renders hardware (OpenSCAD, KiCad files and scripts, FreeCAD, Blender, G-code/slicer profiles, and tools that write or render meshes/CAD/PCB) — CERN-OHL-W 2.0 (SPDX CERN-OHL-W-2.0). Full text: LICENSE (root) / LICENSES/CERN-OHL-W 2.0.
• Code whose end result is software or firmware (firmware, device trees, ground software, analysis/verification/CI tools) — MIT (SPDX MIT). Full text: LICENSES/MIT.
• Documents (Markdown, text, specifications, build guides, and all images — SVG, PNG, JPG, WebP, including renders produced by hardware tools) — CC BY-SA 4.0 (SPDX CC-BY-SA-4.0). Full text: LICENSES/CC-BY-SA 4.0.

See docs/attribution_and_licensing.md for the full policy, the per-subsystem LICENSE federation map, and the CERN-OHL-W "Available Component" treatment of upstream canonical-reference geometry. Revision U, November 2026.

Attribution

"Serenity Tiltrotor Drone Project — hardware CERN-OHL-W 2.0, software MIT, docs CC BY-SA 4.0, based on: · Serenity Firefly-class hull by misubisu (thingiverse.com/thing:7330462, CC BY-SA 4.0) · Variable-area EDF nozzle by BamJr (thingiverse.com/thing:2991269, CC BY 4.0) Include a link to the applicable license and indicate if changes were made."

Component License Map

What This License Covers

Covered under CERN-OHL-W 2.0 (hardware):

• 3D-printable hull, nacelle, and nozzle design files (STL/SCAD/FCStd)
• PCB schematics and Gerber files for Pilot, TACCO, Flight Engineer, Commo, and Observer
• Circuit diagrams, pinout tables, and wiring specifications
• Mechanical drawings and assembly specifications
• Any derived hardware shall carry CERN-OHL-W 2.0 (or a compatible license) and attribute all upstream authors

Covered under CC BY-SA 4.0 (documentation, code, scripts, non-hardware drawings):

• Firmware architecture specifications and algorithm descriptions
• This design document in all its revisions (A–R and beyond)
• Build automation/tooling scripts and non-hardware SVG diagrams
• Any derived works shall carry CC BY-SA 4.0 and attribute all upstream authors

Not covered / separate terms:

• Third-party commercial components (EDFs, ESCs, PocketBeagle 2, etc.) — their own terms
• SiK radio firmware — GPL-3.0
• ArduPilot / QGroundControl — GPL-3.0
• tpm2-tools / tpm2-tss — BSD-2
• CPLD Verilog write-blocker firmware — separately MIT licensed
• Proprietary flight controller firmware (your compiled code) — your terms
• FAA/ICAO regulatory compliance is YOUR responsibility as operator

Patent Notice

This license does NOT grant rights to any patents held by component manufacturers or the design authors. The design uses standard open hardware interfaces (CAN FD, Ethernet, SDIO, SPI, I²C, MAVLink). If you commercialise products based on this design, conduct your own freedom-to-operate analysis. The write-blocker CPLD design implements append-only log enforcement consistent with log data protection principles in NIST SP 800-92 §4.4.2 [REF-NIST-004]; no patent claims are made on the implementation.

Forensic Evidence Integrity Note

The write-blocker and NX enforcement hardware described in this design are intended to support operational log integrity, not forensic evidence collection. They implement log data protection principles consistent with NIST SP 800-92 §4.4.2 [REF-NIST-004]. They are NOT certified forensic tools under NIST CFTT (Computer Forensics Tool Testing) Program specifications or SWGDE (Scientific Working Group on Digital Evidence) standards. Do not use this design as the sole mechanism for evidence preservation in legal proceedings without independent verification of the implementation against your jurisdiction's evidence handling requirements.