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This repository acts as the dynamic backend for OpenRocket's thrust curve data.

This repository utilizesGitHub Pages to act as a static Content Delivery Network (CDN) for the compiled motor data. This ensures high availability and fast downloads for OpenRocket users without requiring a dedicated backend server.

1. Source: John Coker'sThrustCurve.org API (thanks a lot for this incredible resource!).
2. Automation: GitHub Actions runs weekly.
3. Process:
   • Checks for new motors.
   • Downloads raw.eng and.rse files todata/.
   • Compiles them into a SQLite database (motors.db).
   • GZips and hashes the database.
4. Distribution: The resultingmotors.db.gz andmetadata.json are published to GitHub Pages.

The deployment process follows a split-branch strategy:

1. main branch: Contains the source code, scripts, and the raw text cache (.eng/.rse files).
2. gh-pages branch: Containsonly the build artifacts (motors.db.gz andmetadata.json).

Every time theUpdate Workflow runs (scheduled weekly), it commits the new raw data tomain, compiles the database, and force-pushes the binary artifacts togh-pages.

The OpenRocket client (and other interested 3rd parties) can access the live data at the following URLs:

Themetadata.json structure is defined as follows:database_version is a sortable timestamp inYYYYMMDDHHMMSS format.

{"schema_version":2,"database_version":20251225140000,"generated_at":"2025-12-25T14:00:00.000000","last_checked":"2025-12-27T14:00:00.000000","motor_count":1033,"curve_count":1320,"sha256":"a1b2c3d4e5f6...","sha256_gz":"a1b2c3d4e5f6...","sig":"base64-signature...","download_url":"https://openrocket.github.io/motor-database/motors.db.gz"}

Signature notes:

• sig is an Ed25519 signature overopenrocket-motordb-v1\n{database_version}\n{sha256_gz}\n.
• sha256_gz is the SHA-256 of the gzipped database;sha256 is kept for backward compatibility.
• key_id is optional for key rotation.

The SQLite schema lives inschema/V1__initial_schema.sql and is optimized for fast client lookups. Foreign keys are enabled with cascade deletes.

manufacturers          motors              thrust_curves           thrust_data┌──────────────┐      ┌──────────────┐     ┌──────────────┐        ┌──────────────┐│ id (PK)      │◄─────│ mfr_id (FK)  │     │ id (PK)      │◄───────│ curve_id(FK) ││ name         │  1:N │ id (PK)      │◄────│ motor_id(FK) │    1:N │ id (PK)      ││ abbrev       │      │ tc_motor_id  │ 1:N │ tc_simfile_id│        │ time_seconds │└──────────────┘      │ designation  │     │ source       │        │ force_newtons│                      │ impulse_class│     │ format       │        └──────────────┘                      │ ...          │     │ ...          │                      └──────────────┘     └──────────────┘

• manufacturers →motors: One manufacturer has many motors
• motors →thrust_curves: One motor can have multiple thrust curves (different sources/measurements)
• thrust_curves →thrust_data: One curve has many time/thrust data points

meta

Keys stored:schema_version,database_version,generated_at,motor_count,curve_count.

manufacturers

motors

thrust_curves

Each motor can have multiple thrust curves from different sources (certification, manufacturer, user submissions).

thrust_data

Time/thrust data points for each thrust curve.

1. pip install -r scripts/requirements.txt
2. python scripts/fetch_updates.py (Downloads new files)
3. python scripts/build_database.py (Generates DB)

• state/last_update.json: timestamp of the most recent data/metadata change detected byscripts/fetch_updates.py.
• state/last_check.json: timestamp of the most recent update check, even if no changes were found.
• state/last_build.json: input hash + build outputs used byscripts/build_database.py to skip rebuilding when the schema/data inputs are unchanged.

Signing is done in CI after the database build completes.

What is signed:

• Canonical message:openrocket-motordb-v1\n{database_version}\n{sha256_gz}\n
• sha256_gz is the SHA-256 ofmotors.db.gz (the compressed DB)

What gets added tometadata.json by the signing step:

• sha256_gz: SHA-256 ofmotors.db.gz (currently matchessha256)
• sig: base64-encoded Ed25519 signature of the canonical message
• key_id (optional): identifier for key rotation

How CI handles it:

• .github/workflows/update-motors.yml installscryptography
• It runspython scripts/sign_database.py motors.db.gz metadata.json
• The private key is provided via secrets

Set the private key in:

• MOTOR_DB_PRIVATE_KEY_BASE64 (Ed25519 private key, DER or PEM encoded, then base64)
• MOTOR_DB_KEY_ID (optional, for key rotation)

Manual signing:python scripts/sign_database.py motors.db.gz metadata.json

1. pip install -r scripts/requirements.txt
2. pip install pytest cryptography
3. pytest

The motor data in this repository is cached fromThrustCurve.org.

• Source: ThrustCurve.org (maintained by John Coker).
• Copyright: The data files (.eng,.rse) retain their original internal copyright headers.
• Usage: This data is intended for use within OpenRocket. If you wish to use this data for other projects, please use theThrustCurve.org API directly to ensure you are respecting the latest updates and restrictions.