OpenRocket Motor Database

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

Deployment & API Endpoints

This repository utilizes GitHub 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.

Architecture

1. Source: John Coker's ThrustCurve.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 to data/.
   • Compiles them into a SQLite database (motors.db).
   • GZips and hashes the database.
4. Distribution: The resulting motors.db.gz and metadata.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: Contains only the build artifacts (motors.db.gz and metadata.json).

Every time the Update Workflow runs (scheduled weekly), it commits the new raw data to main, compiles the database, and force-pushes the binary artifacts to gh-pages.

Public Endpoints

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

File	URL	Description
Manifest	https://openrocket.github.io/motor-database/metadata.json	Lightweight JSON file. Contains database_version, generated_at, last_checked, sha256, and the signature fields for verification. Checked by the client on startup.
Database	https://openrocket.github.io/motor-database/motors.db.gz	GZipped SQLite database. Downloaded by the client only if the manifest version differs from the local cache.

Manifest Format

The metadata.json structure is defined as follows: database_version is a sortable timestamp in YYYYMMDDHHMMSS 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 over openrocket-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.

Database Schema

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

Entity Relationship

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

Tables and Columns

meta

Column	Type	Notes
key	TEXT	Primary key
value	TEXT	Required

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

---

manufacturers

Column	Type	Notes
id	INTEGER	Primary key, autoincrement
name	TEXT	Required, unique (e.g. "AeroTech")
abbrev	TEXT	Short name (e.g. "AT")

---

motors

Column	Type	Notes
id	INTEGER	Primary key, autoincrement
manufacturer_id	INTEGER	FK to manufacturers.id
tc_motor_id	TEXT	ThrustCurve.org motor ID
designation	TEXT	Required (e.g. "H128W")
common_name	TEXT	Display name (e.g. "H128")
impulse_class	TEXT	Letter class: A, B, C, ... O
diameter	REAL	Motor diameter in mm
length	REAL	Motor length in mm
total_impulse	REAL	Total impulse in Ns
avg_thrust	REAL	Average thrust in N
max_thrust	REAL	Maximum thrust in N
burn_time	REAL	Burn time in seconds
propellant_weight	REAL	Propellant weight in grams
total_weight	REAL	Total weight in grams
type	TEXT	"SU" (single-use), "reload", "hybrid"
delays	TEXT	Available delays, e.g. "0,6,10,14"
case_info	TEXT	Case info, e.g. "RMS 38/360"
prop_info	TEXT	Propellant info, e.g. "White Lightning"
sparky	INTEGER	1 if sparky motor, 0 otherwise
info_url	TEXT	URL to motor info page
data_files	INTEGER	Number of data files on ThrustCurve
updated_on	TEXT	Last update date from ThrustCurve
description	TEXT	RASP file comments (header notes, newlines removed)
source	TEXT	Data source (e.g. "thrustcurve.org", "manual")

---

thrust_curves

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

Column	Type	Notes
id	INTEGER	Primary key, autoincrement
motor_id	INTEGER	FK to motors.id, cascade delete
tc_simfile_id	TEXT	ThrustCurve.org simfile ID
source	TEXT	"cert", "mfr", or "user"
format	TEXT	"RASP" or "RSE"
license	TEXT	"PD", "free", or other
info_url	TEXT	URL to simfile info page
data_url	TEXT	URL to download simfile
total_impulse	REAL	Calculated total impulse (Ns)
avg_thrust	REAL	Calculated average thrust (N)
max_thrust	REAL	Calculated max thrust (N)
burn_time	REAL	Calculated burn time (s)

---

thrust_data

Time/thrust data points for each thrust curve.

Column	Type	Notes
id	INTEGER	Primary key, autoincrement
curve_id	INTEGER	FK to thrust_curves.id, cascade delete
time_seconds	REAL	Time in seconds
force_newtons	REAL	Thrust force in Newtons

---

Indices

Index	Table	Columns	Purpose
idx_motor_mfr	motors	manufacturer_id	Filter by manufacturer
idx_motor_diameter	motors	diameter	Filter by size
idx_motor_impulse	motors	total_impulse	Filter by impulse
idx_motor_impulse_class	motors	impulse_class	Filter by class (A-O)
idx_motor_tc_id	motors	tc_motor_id	Lookup by ThrustCurve ID
idx_curve_motor	thrust_curves	motor_id	Get curves for a motor
idx_curve_simfile	thrust_curves	tc_simfile_id	Lookup by simfile ID
idx_thrust_curve	thrust_data	curve_id	Get data for a curve

Manual Usage

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 Files

• state/last_update.json: timestamp of the most recent data/metadata change detected by scripts/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 by scripts/build_database.py to skip rebuilding when the schema/data inputs are unchanged.

Signing

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 of motors.db.gz (the compressed DB)

What gets added to metadata.json by the signing step:

• sha256_gz: SHA-256 of motors.db.gz (currently matches sha256)
• 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 installs cryptography
• It runs python 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

Unit Tests

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

Data Attribution & License

The motor data in this repository is cached from ThrustCurve.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 the ThrustCurve.org API directly to ensure you are respecting the latest updates and restrictions.