03 · Orrery — Data Catalog

April 2026 · v1.0 · Part of the Orrery Concept Package (00 through 05)

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Purpose

This document catalogs every data source, constant, schema, and API that Orrery uses. It is the primary reference for anyone adding a mission, correcting a number, or building on the codebase. Every value in the product traces back to something in this document.

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1. Orbital mechanics

1.1 Physical constants

Constant	Value	Source
Gravitational parameter (Sun) μ	4π² AU³/yr²	Keplerian simplification; GM☉ = 1.327×10²⁰ m³/s²
AU to km	149,597,870.7 km	IAU 2012
AU to light-minutes	8.3167 min	Derived from c = 299,792.458 km/s
AU/yr to km/s	4.7404 km/s	Derived
Earth radius	6,371 km	IAU
Moon radius	1,737.4 km	IAU
Earth–Moon mean distance	384,400 km	IAU
Earth–Sun mean distance	1.000 AU (definition)	IAU

1.2 Epoch

All orbital elements use the J2000.0 epoch (January 1.5, 2000, 12:00 TT = JD 2451545.0). Day offsets from J2000 are used throughout the mission trajectory computation.

1.3 Planetary orbital elements

Mean orbital radii and angular velocity used in Orrery's Keplerian model. These are mean values — Orrery does not model orbital eccentricity for planets in the explorer view, trading precision for visual clarity and performance. The mission configurator uses a Lambert solver for trajectory accuracy.

Planet	Semi-major axis	Period	Mean angular velocity	J2000 mean longitude L₀	Inclination to ecliptic
Mercury	0.387 AU	87.97 d	2π / 87.97 d	Varies	7.00°
Venus	0.723 AU	224.70 d	2π / 224.70 d	Varies	3.39°
Earth	1.000 AU	365.25 d	2π / 365.25 d	1.753 rad	0.00° (reference)
Mars	1.524 AU	686.97 d	2π / 686.97 d	6.203 rad	1.85°
Jupiter	5.203 AU	4332.59 d	2π / 4332.59 d	—	1.30°
Saturn	9.537 AU	10759.22 d	2π / 10759.22 d	—	2.49°
Uranus	19.19 AU	30688.50 d	2π / 30688.50 d	—	0.77°
Neptune	30.07 AU	60182.00 d	2π / 60182.00 d	—	1.77°

Source: JPL Planetary Fact Sheets — https://nssdc.gsfc.nasa.gov/planetary/factsheet/

1.4 Mission orbital position computation

For the porkchop plot and mission arc, planetary positions are computed using:

angle(t) = L₀ + ω × t
x = r × cos(angle)
y = r × sin(angle) × cos(inclination)
z = r × sin(angle) × sin(inclination)

Where t is days from J2000, ω is angular velocity in rad/day, and r is the mean orbital radius in AU.

1.5 Lambert solver

The porkchop plot is computed using a bisection-based Lambert solver:

• Method: Lagrange-Gauss short-way formulation
• Iterations: 52 per cell (convergence to ≤10⁻⁸ tolerance)
• Grid: 140 × 80 = 11,200 trajectory solutions computed at startup
• X axis: Departure date (days from reference)
• Y axis: Time of flight (days)
• Z / colour: C3 launch energy (km²/s²), rendered as delta-v approximation
• Reference: Bate, Mueller & White, Fundamentals of Astrodynamics (1971), Chapter 5

1.6 Transfer orbit — Hohmann approximation

For the mission arc fly screen, spacecraft position is interpolated along a quadratic Bézier curve between Earth's departure position and Mars's arrival position. This is a visual approximation of the true Keplerian transfer ellipse, used for rendering only. Telemetry (velocity, distance) is computed from the vis-viva equation applied to the actual transfer orbit elements.

Vis-viva: v = √(μ × (2/r − 1/a))

Where:

• μ = 4π² AU³/yr² (solar gravitational parameter)
• r = current heliocentric distance (AU)
• a = semi-major axis of transfer orbit = (R_Earth + R_Mars) / 2 = 1.262 AU

1.7 Visual scale — solar system explorer

Planets are not shown at true scale — they would be invisible. The visual orbital radii used in the 2D and 3D explorer are:

Body	True semi-major axis	Visual orbital radius (px)	Scale factor
Mercury	0.387 AU	52 px	—
Venus	0.723 AU	83 px	—
Earth	1.000 AU	113 px	Reference
Mars	1.524 AU	155 px	—
Asteroid belt	2.2–3.2 AU	192–237 px	—
Jupiter	5.203 AU	248 px	—
Saturn	9.537 AU	320 px	—
Uranus	19.19 AU	378 px	—
Neptune	30.07 AU	430 px	—
Kuiper Belt	30–50 AU	438–470 px	—

The scale is manually compressed (not a pure power law) to keep all planets visible on a single screen while preserving relative ordering. The auToPx() function in P01 implements a linear interpolation between these anchor points.

1.8 Visual scale — Earth orbit viewer

The Earth orbit viewer uses a logarithmic scale to accommodate the ISS-to-JWST range of 3,750×:

visual_r = EARTH_VIS_R + LOG_K × log₁₀(1 + alt_km / 100)

Where EARTH_VIS_R = 38 px (visual Earth radius) and LOG_K = 54 px (scale factor per decade of altitude). This maps ISS (408 km) to ~70 px and JWST (1,500,000 km) to ~244 px.

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2. Mission data schema

Every mission in Orrery is defined by a JavaScript object conforming to this schema. This schema covers both Mars and Moon missions.

2.1 Required fields

Field	Type	Description
id	string	Unique identifier, kebab-case. e.g. "curiosity", "apollo11m"
name	string	Display name. e.g. "Curiosity", "Apollo 11"
agency	string	Primary agency key. Must match LOGOS dict. e.g. "NASA", "CNSA"
agency_full	string	Full display name. e.g. "NASA / JPL"
sector	string	"gov", "private", or "mine"
dest	string	"MARS" or "MOON"
color	string	Hex colour for agency. e.g. "#0B3D91"
year	number or string	Launch year. Use string for ranges: "2026–28"
type	string	Mission type description. e.g. "ROVER · ACTIVE"
status	string	"FLOWN", "ACTIVE", "PLANNED", or "MINE"
dep	string	Departure date, human-readable. e.g. "Nov 26, 2011"
arr	string	Arrival date, human-readable. e.g. "Aug 6, 2012"
tof	number or null	Transit time in days. null for TBD planned missions
vehicle	string	Launch vehicle name
description	string	Editorial description, 2–4 sentences, Crimson Pro italic in UI
data_quality	string	"good", "partial", "reconstructed", or "planned"
credit	string	Full image/data credit line
links	array	Array of {l, u, t} educational link objects (see 2.3)
missionable	boolean	true only for Mars — shows "Plan a mission" CTA

2.2 Optional fields

Field	Type	Description
j2000	number or null	Days from J2000 epoch at departure. Used for trajectory preview drawing. null for Moon missions and TBD planned missions
collabs	array	Array of collaborating agency keys. e.g. ["ESA", "CNES"]
first	string	The mission's "first" — shown as a coloured badge in the card
payload	string	Payload mass description. e.g. "899 kg"
dv	string	Delta-v figure. e.g. "~6.1 km/s"
data_note	string	Explanation for non-"good" data quality. Shown as a left-border note in the panel
gallery_query	string	Search query string for NASA Images API. NASA missions only
gallery_imgs	array	Array of direct image URLs. For non-NASA missions. See section 4

2.3 Educational link object

{ l: "Link label", u: "https://...", t: "intro" }

t (tier) must be one of:

• "intro" — Wikipedia, NASA fact pages, agency overview pages
• "core" — MIT OCW, detailed technical pages, mission science overviews
• "deep" — Peer-reviewed papers, JPL technical reports, primary sources

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3. Data quality system

Every mission carries a data_quality field that is displayed honestly in the UI.

Value	Badge	Meaning
"good"	(none)	Primary sources available. Orbital elements from published data. Images from official agency archives
"partial"	⚠ PARTIAL DATA	Some data gaps. Orbital elements good; imagery sparse or selectively released. Must be explained in data_note
"reconstructed"	◈ RECONSTRUCTED	Orbital elements computed from published launch parameters. No primary science data available. Surface imagery absent or unusable. Must be explained in data_note
"planned"	◌ PLANNED	Mission not yet flown. Parameters from published mission design documents

Known reconstructed missions

Mission	What is reconstructed	Source used
Mars 3	Orbital elements computed from Proton-K launch date and published trajectory parameters	Siddiqi, Beyond Earth (NASA SP-4251, 2018)
Soviet Luna missions (pre-1970)	Partial orbital elements	Siddiqi, op. cit.

Known partial-data missions

Mission	What is partial	Note
Mangalyaan	Imagery selectively released; telemetry reconstructed	Mission lost contact April 2022
Tianwen-1 / Zhurong	Selected data via CNSA official channels only	Zhurong status uncertain as of 2023

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4. Image sources

4.1 NASA Image and Video Library

API: https://images-api.nasa.gov/search

Parameters:

q=[search query]
media_type=image
page_size=9

License: U.S. Government works — not subject to copyright in the United States. Free for educational use. Must credit NASA and the relevant centre (JPL, GSFC, JSC, etc.).

Credit format: © NASA/JPL-Caltech — U.S. Government work · Public domain

Used for: All NASA mission gallery panels. Query strings are defined per mission in gallery_query field.

Rate limiting: No authentication required for basic search. No formal rate limit documented; use conservatively.

4.2 ESA Multimedia Archive

URL: https://www.esa.int/ESA_Multimedia/

License: CC BY-SA 3.0 IGO. May be used freely with attribution and share-alike. The IGO (Intergovernmental Organisation) variant is specifically designed for use by Wikipedia and similar projects.

Credit format: © ESA — CC BY-SA 3.0 IGO — esa.int

Mars Express images: 1,430+ images available. HRSC stereo camera images released under CC BY-SA IGO.

Used for: Mars Express gallery. ESA mission panels.

Reference: https://www.esa.int/About_Us/Digital_Agenda/Open_Access_and_Creative_Commons

4.3 ISRO

URL: https://www.isro.gov.in

License: Available for educational and informational use. No explicit CC license. Do not use for commercial purposes.

Credit format: © ISRO — Educational use — isro.gov.in

Mangalyaan (MOM) images: Mars Colour Camera (MCC) images released publicly. Mars Atlas (2015, 120 pages) available as PDF.

Chandrayaan-3: Post-landing images released publicly.

Used for: Mangalyaan and Chandrayaan gallery panels.

4.4 CNSA

URL: https://www.cnsa.gov.cn

License: Official releases. No explicit CC license. Use with attribution for educational context.

Credit format: © CNSA/CLEP — Official release — cnsa.gov.cn

Tianwen-1 / Zhurong: Selected images released through CNSA and CLEP (China Lunar Exploration Program). Some available via Wikimedia Commons.

Chang'e missions: Official surface imagery released post-landing.

Used for: CNSA mission gallery panels.

4.5 Wikimedia Commons — curated static images

For missions where a live API fetch is not available, gallery images are served from Wikimedia Commons via direct URL. These are stable thumbnail URLs following the pattern:

https://upload.wikimedia.org/wikipedia/commons/thumb/[a]/[ab]/[filename]/[width]px-[filename]

All Wikimedia Commons images carry their own license per file. Before adding an image, verify:

1. The image page license tag (must be compatible with educational use)
2. The original source (prefer agency-released over third-party photographs)
3. The attribution requirements

Research task (03 phase): Curate and verify 3–5 Wikimedia Commons URLs per non-NASA mission for the gallery panels. Document source, license, and attribution per image.

4.6 Soviet/Russian archive — special case

Soviet-era imagery (Luna programme, Lunokhod) is patchy. Known accessible sources:

Source	Content	Notes
Roscosmos press archive	Modern releases only	Limited Soviet-era content
TASS photo archive	Historical mission team photos	May require licensing for some uses
Wikimedia Commons — Soviet space	Community-uploaded, varies by file	Check each image individually
Siddiqi, Beyond Earth (NASA SP-4251)	Comprehensive mission reference	Public domain NASA publication

Strategy for sparse missions: For missions where no usable imagery exists (e.g. Mars 3 surface transmission), the gallery panel shows an honest placeholder with a link to the best available secondary source, and the data_quality badge accurately reflects this.

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5. Agency logos

All agency logos are used under nominative use — for identification and attribution purposes only, in a non-commercial educational context. Orrery does not claim endorsement by any agency.

Agency	Wikimedia Commons URL	Background colour	License status
NASA	https://upload.wikimedia.org/wikipedia/commons/thumb/e/e5/NASA_logo.svg/200px-NASA_logo.svg.png	#0B3D91	Trademark — nominative use
ESA	https://upload.wikimedia.org/wikipedia/commons/thumb/7/76/ESA_logo_simple.svg/200px-ESA_logo_simple.svg.png	#1C3C8A	CC BY-SA 3.0 IGO
CNSA	https://upload.wikimedia.org/wikipedia/commons/thumb/a/ab/CNSA_logo.svg/200px-CNSA_logo.svg.png	#DE2910	Trademark — nominative use
ISRO	https://upload.wikimedia.org/wikipedia/commons/thumb/b/b4/Indian_Space_Research_Organisation_Logo.svg/200px-Indian_Space_Research_Organisation_Logo.svg.png	#1a1a2e	Trademark — nominative use
Roscosmos	https://upload.wikimedia.org/wikipedia/commons/thumb/a/ac/Roscosmos_logo_en.svg/200px-Roscosmos_logo_en.svg.png	#0d0d1a	Trademark — nominative use
UAE/MBRSC	https://upload.wikimedia.org/wikipedia/en/thumb/e/e0/Mohammed_Bin_Rashid_Space_Centre_Logo.png/200px-Mohammed_Bin_Rashid_Space_Centre_Logo.png	#ffffff	Trademark — nominative use
JAXA	https://upload.wikimedia.org/wikipedia/commons/thumb/9/9f/JAXA_logo_2020.svg/200px-JAXA_logo_2020.svg.png	#0062AC	Trademark — nominative use
SpaceX	https://upload.wikimedia.org/wikipedia/commons/thumb/d/de/SpaceX-Logo.svg/200px-SpaceX-Logo.svg.png	#000000	Trademark — nominative use

Implementation: The logoHTML() function renders the real logo image on top of an always-visible text abbreviation fallback. If the image fails to load (offline use, URL change), the fallback renders correctly. In production, logos should be hosted locally from official media kits.

Trademark notices: Every panel footer includes: "Logos are trademarks of their respective agencies · used for educational identification only."

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6. Orbital data for small solar system bodies

6.1 Asteroid belt notable objects

Body	Semi-major axis	Period	Inclination	Source
Ceres	2.769 AU	4.61 yr	10.59°	JPL Small-Body Database
Vesta	2.361 AU	3.63 yr	7.14°	JPL Small-Body Database

JPL Small-Body Database: https://ssd.jpl.nasa.gov/sbdb.cgi

6.2 Kuiper Belt objects

Body	Semi-major axis	Period	Inclination	Note
Pluto	39.48 AU	248.0 yr	17.14°	IAU dwarf planet
Eris	67.86 AU (mean)	559 yr	44.04°	Scattered disc object
Makemake	45.79 AU	309.9 yr	28.96°	Classical KBO
Haumea	43.13 AU	284.1 yr	28.19°	Classical KBO

6.3 Notable comets

Body	Perihelion q	Aphelion Q	Period	Inclination	Note
Halley's Comet	0.586 AU	35.1 AU	75.3 yr	162.3°	Retrograde orbit
67P/C-G	1.21 AU	5.68 AU	6.44 yr	7.04°	Rosetta mission target
ʻOumuamua	0.255 AU	—	—	122.7°	Hyperbolic — interstellar

Source: JPL Horizons — https://ssd.jpl.nasa.gov/horizons/

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7. Earth orbit data

7.1 Orbital objects in P05

All data from publicly available sources. Altitudes are mean values; actual orbits vary.

Object	Regime	Altitude	Period	Inclination	Agency	Source
ISS	LEO	408 km	92.9 min	51.6°	Multi-agency	NASA
Tiangong	LEO	389 km	91.5 min	41.5°	CNSA	CNSA
Hubble	LEO	547 km	95.4 min	28.5°	NASA/ESA	NASA
GPS constellation	MEO	20,200 km	717.9 min	55.0°	USAF	GPS.gov
Galileo constellation	MEO	23,222 km	844.8 min	56.0°	EU/ESA	ESA
GLONASS	MEO	19,100 km	675.7 min	64.8°	Roscosmos	Roscosmos
BeiDou (MEO)	MEO	21,528 km	760 min	55.0°	CNSA	CNSA
GOES (GEO)	GEO	35,786 km	1436 min	0.0°	NOAA/NASA	NOAA
Chandra	HEO	9,942–133,000 km	3808 min	76.7°	NASA	CXC
XMM-Newton	HEO	7,365–113,946 km	3168 min	40.0°	ESA	ESA
LRO	Lunar orbit	50 km (Moon)	118 min	90.0°	NASA	NASA
JWST	L2	1,500,000 km	—	—	NASA/ESA/CSA	NASA
Gaia	L2	1,500,000 km	—	—	ESA	ESA

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8. Mission trajectory data for the library panel

For the 2D trajectory preview in the mission library, trajectories are drawn using each mission's J2000 departure day and transit time. Planetary positions are computed at departure and arrival using the formulas in section 1.4.

Moon missions use a separate Earth-Moon diagram (not solar-system scale). The dest field controls which renderer is used.

8.1 Mars mission J2000 day offsets

Mission	J2000 departure	Computed from
Mariner 4	−12,820	Nov 28, 1964
Mars 3	−10,445	May 28, 1971
Viking 1	−8,899	Aug 20, 1975
Mars Pathfinder	−1,123	Dec 4, 1996
Mars Express	1,248	Jun 2, 2003
Curiosity	4,347	Nov 26, 2011
MAVEN	4,969	Nov 18, 2013
Mangalyaan	4,962	Nov 5, 2013
InSight	6,699	May 5, 2018
Hope Probe	7,500	Jul 19, 2020
Tianwen-1	7,508	Jul 23, 2020
Perseverance	7,511	Jul 30, 2020

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9. Educational link system

Orrery uses a three-tier educational link system, colour-coded consistently across all screens:

Tier	Colour	Purpose	Examples
INTRO	Teal #4ecdc4	Wikipedia, NASA fact pages, agency mission pages	Wikipedia articles, nasa.gov/mission/
CORE	Blue #7b9cff	Technical explainers, MIT OCW, deeper mission science	MIT OpenCourseWare, JPL education pages
DEEP	Red #ff9090	Peer-reviewed papers, JPL technical reports, primary sources	Science, Nature, AJ, NTRS

Key curated links (reused across screens)

Link	Tier	URL
Hohmann transfer orbit	INTRO	https://en.wikipedia.org/wiki/Hohmann_transfer_orbit
Tsiolkovsky rocket equation	INTRO	https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation
Porkchop plot	CORE	https://en.wikipedia.org/wiki/Porkchop_plot
JPL launch windows lesson	CORE	https://www.jpl.nasa.gov/edu/resources/lesson-plan/lets-go-to-mars-calculating-launch-windows/
NASA Glenn rocket equation	CORE	https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/ideal-rocket-equation/
Lagrange point	CORE	https://en.wikipedia.org/wiki/Lagrange_point
Lunar water ice (Science 2018)	DEEP	https://www.science.org/doi/10.1126/science.aap8637
Batygin & Brown — Planet Nine (AJ 2016)	DEEP	https://iopscience.iop.org/article/10.3847/0004-6256/151/2/22

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10. One-off research plan for sparse missions

The following missions require dedicated research sessions to fill gaps before 02 (formal project concept) is finalised. Each session produces: curated image URLs, verified orbital data, and updated data_note text.

Mission	Gap	Research approach	Priority
Mars 3	No usable surface imagery; team photos only	Wikimedia Commons excavation; TASS historical archive; Siddiqi NASA SP-4251	HIGH
Luna programme (1966–1976)	Variable data quality across 24 missions	Siddiqi; Soviet Space Encyclopaedia; Wikimedia Commons	MEDIUM
Mangalyaan	Full imagery catalogue not publicly indexed	ISRO image gallery manual curation; Indian news archives	MEDIUM
Chang'e 4 / Zhurong	Current status uncertain 2023+	CNSA official announcements; CLEP press releases	MEDIUM
Soviet Lunokhod missions	Routes and images partially documented	LROC spotting images (NASA); Wikimedia Commons	LOW
Beresheet (Israel, 2019)	Crashed — limited official imagery	SpaceIL press archive; Wikimedia Commons	LOW

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11. Credit format reference

Every image, logo, and data source in Orrery uses one of the following credit formats:

NASA imagery:© NASA/[Centre] — U.S. Government work · Public domain

ESA imagery:© ESA — CC BY-SA 3.0 IGO — esa.int

ISRO imagery:© ISRO — Educational use — isro.gov.in

CNSA imagery:© CNSA/CLEP — Official release — cnsa.gov.cn

Roscosmos / Soviet:© Roscosmos / Soviet Space Program — Historical archive

JAXA imagery:© JAXA — jaxa.jp

Wikimedia Commons image:[Author], [License], via Wikimedia Commons

Agency logos (all):[Agency] logo is a trademark of [Agency] · Used for educational identification only

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