We set up a real-time solar-system tracker that fetches orbital elements for small bodies (asteroids/meteoroids) from JPL SBDB, propagates their heliocentric positions, visualizes them in 3D, and computes live distances between objects. Add objects by name (or designation). The server fetches orbital elements and the app updates positions in real time. { "name": "cosmo-tracker", "version": "1.0.0", "description": "Real-time tracker for asteroids, meteoroids and other small bodies using JPL SBDB orbital elements.", "main": "server.js", "scripts": { "start": "node server.js" }, "author": "Generated", "license": "MIT", "dependencies": { "cors": "^2.8.5", "express": "^4.18.2" } } const express = require('express'); const path = require('path'); const cors = require('cors'); const { computePositionFromElements, jdNow } = require('./lib/ephem'); const app = express(); app.use(cors()); app.use(express.json()); app.use(express.static(path.join(__dirname, 'public'))); // In-memory store of tracked objects const objects = {}; // key -> { name, elements, addedAt } // Helper to fetch orbital elements from JPL SBDB async function fetchOrbitalElements(designation) { const url = `https://ssd-api.jpl.nasa.gov/sbdb.api?des=${encodeURIComponent(designation)}&phys-par=0`; const res = await fetch(url); if (!res.ok) { throw new Error(`SBDB request failed: ${res.status}`); } const data = await res.json(); if (data && data.object && data.object.id) { // SBDB returns orbit.elements as array of objects {name, value} const elementsRaw = (data.orbit && data.orbit.elements) || []; const map = {}; elementsRaw.forEach(e => { if (e && e.name && (e.value !== undefined)) { map[e.name.toLowerCase()] = e.value; } }); // Expected element keys in SBDB: a, e, i, om (long asc node), w (arg peri), ma (mean anomaly), epoch // Fallbacks: some keys might be spelled differently; we try typical names const a = parseFloat(map['a'] || map['a (au)'] || map['a (au)'] || map['semi-major axis'] || NaN); const e = parseFloat(map['e'] || map['eccentricity'] || NaN); const i = parseFloat(map['i'] || map['inclination'] || NaN); const om = parseFloat(map['om'] || map['node'] || map['long. of ascending node'] || NaN); const w = parseFloat(map['w'] || map['arg of perihelion'] || map['argument of perihelion'] || NaN); const ma = parseFloat(map['ma'] || map['mean anomaly'] || NaN); // Epoch may be provided as JD string or as number let epoch = map['epoch'] || map['epoch (jd)'] || map['epoch jd'] || map['epoch (julian)'] || null; if (epoch !== null) { epoch = parseFloat(String(epoch).split(' ')[0]); } if (isNaN(a) || isNaN(e) || isNaN(i) || isNaN(om) || isNaN(w) || isNaN(ma) || isNaN(epoch)) { throw new Error('Incomplete orbital elements returned by SBDB.'); } return { a, e, i, om, w, ma, epoch }; } else { throw new Error('Object not found in SBDB'); } } // Add object by name/designation app.post('/api/objects', async (req, res) => { try { const name = (req.body && req.body.name) || req.query.name; if (!name) { return res.status(400).json({ error: 'missing name in body or query' }); } const key = name.trim().toLowerCase(); if (objects[key]) { return res.status(200).json({ message: 'already tracked', object: objects[key] }); } const elements = await fetchOrbitalElements(name); objects[key] = { id: key, name: name.trim(), elements, addedAt: Date.now() }; return res.status(201).json({ message: 'added', object: objects[key] }); } catch (err) { return res.status(500).json({ error: String(err.message || err) }); } }); // Remove object app.delete('/api/objects/:id', (req, res) => { const id = req.params.id; if (!objects[id]) return res.status(404).json({ error: 'not found' }); delete objects[id]; return res.status(200).json({ message: 'removed' }); }); // List objects with live positions and pairwise distances (distances in km) app.get('/api/objects', (req, res) => { try { const nowJD = jdNow(); const list = []; for (const key of Object.keys(objects)) { const obj = objects[key]; const pos = computePositionFromElements(obj.elements, nowJD); // pos: { x,y,z } in AU list.push({ id: obj.id, name: obj.name, elements: obj.elements, position: pos }); } // Compute pairwise distances (km) const AU_KM = 149597870.7; const pairs = []; for (let i = 0; i < list.length; i++) { for (let j = i + 1; j < list.length; j++) { const a = list[i].position; const b = list[j].position; const dx = (a.x - b.x) * AU_KM; const dy = (a.y - b.y) * AU_KM; const dz = (a.z - b.z) * AU_KM; const distKM = Math.sqrt(dx * dx + dy * dy + dz * dz); pairs.push({ a: list[i].id, b: list[j].id, distance_km: distKM }); } } return res.json({ timestamp_jd: nowJD, objects: list, pairs }); } catch (err) { return res.status(500).json({ error: String(err) }); } }); // Serve frontend app.get('/', (req, res) => { res.sendFile(path.join(__dirname, 'public', 'index.html')); }); const PORT = process.env.PORT || 3000; app.listen(PORT, () => { console.log(`Cosmo Tracker server running on port ${PORT}`); }); // Utility math & Kepler propagation to compute heliocentric ecliptic coordinates from orbital elements // All distances returned in AU. Angles provided/expected in degrees in the elements object. const DEG2RAD = Math.PI / 180; const RAD2DEG = 180 / Math.PI; const GAUSSIAN_K = 0.01720209895; // Gaussian gravitational constant (rad/day) * sqrt(AU^3) // Return current Julian Day (UTC) function jdNow() { const now = new Date(); return dateToJD(now); } function dateToJD(date) { // Convert JS Date to Julian Day const year = date.getUTCFullYear(); let month = date.getUTCMonth() + 1; const day = date.getUTCDate() + (date.getUTCHours() / 24) + (date.getUTCMinutes() / 1440) + (date.getUTCSeconds() / 86400) + (date.getUTCMilliseconds() / 86400000); let Y = year; let M = month; if (M <= 2) { Y = Y - 1; M = M + 12; } const A = Math.floor(Y / 100); const B = 2 - A + Math.floor(A / 4); const JD = Math.floor(365.25 * (Y + 4716)) + Math.floor(30.6001 * (M + 1)) + day + B - 1524.5; return JD; } // Solve Kepler's equation M = E - e*sin(E) for E (radians), iterative Newton-Raphson function solveKepler(M, e, tol = 1e-12, maxIter = 50) { let E = M; for (let i = 0; i < maxIter; i++) { const f = E - e * Math.sin(E) - M; const fp = 1 - e * Math.cos(E); const dE = -f / fp; E += dE; if (Math.abs(dE) < tol) break; } return E; } // Compute position from orbital elements for given Julian day jd // elements: { a (AU), e, i (deg), om (deg) [longitude of ascending node], w (deg) [argument of perihelion], ma (deg) [mean anomaly], epoch (JD) } function computePositionFromElements(elements, jd) { const a = parseFloat(elements.a); const e = parseFloat(elements.e); const i = parseFloat(elements.i) * DEG2RAD; const om = parseFloat(elements.om) * DEG2RAD; const w = parseFloat(elements.w) * DEG2RAD; let ma = parseFloat(elements.ma) * DEG2RAD; const epoch = parseFloat(elements.epoch); // JD // Mean motion (rad/day) using Gaussian gravitational constant (approx) const n = GAUSSIAN_K / Math.pow(a, 1.5); // delta days from epoch const dt = jd - epoch; // Advance mean anomaly const M = normalizeAngleRad(ma + n * dt); // Solve Kepler const E = solveKepler(M, e); // True anomaly const cosE = Math.cos(E); const sinE = Math.sin(E); const sqrt1me2 = Math.sqrt(1 - e * e); const v = Math.atan2(sqrt1me2 * sinE, cosE - e); // radians // Distance r in AU const r = a * (1 - e * cosE); // Argument of latitude = w + v const u = w + v; // Coordinates in ecliptic plane (heliocentric) const x = r * (Math.cos(om) * Math.cos(u) - Math.sin(om) * Math.sin(u) * Math.cos(i)); const y = r * (Math.sin(om) * Math.cos(u) + Math.cos(om) * Math.sin(u) * Math.cos(i)); const z = r * (Math.sin(u) * Math.sin(i)); return { x, y, z }; } function normalizeAngleRad(theta) { let t = theta % (2 * Math.PI); if (t < 0) t += 2 * Math.PI; return t; } module.exports = { jdNow, dateToJD, computePositionFromElements, solveKepler }; Cosmo Tracker

Cosmo Tracker

:root { --bg: #061022; --panel: rgba(255,255,255,0.04); --accent: #7dd3fc; --muted: #9aa8b2; --white: #e6f0f6; } * { box-sizing: border-box; } body { margin: 0; font-family: Inter, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial; background: linear-gradient(180deg, #041022 0%, #071329 100%); color: var(--white); height: 100vh; display: flex; flex-direction: column; } header { padding: 12px 18px; display: flex; align-items: center; justify-content: space-between; gap: 12px; } header h1 { margin: 0; font-size: 18px; color: var(--accent); } .controls { display: flex; gap: 8px; align-items: center; } input#nameInput { padding: 8px 10px; border-radius: 6px; border: none; min-width: 320px; background: rgba(255,255,255,0.03); color: var(--white); } button { padding: 8px 12px; border-radius: 6px; border: none; background: var(--panel); color: var(--white); cursor: pointer; } main { display: flex; flex: 1; gap: 12px; padding: 12px; height: calc(100vh - 120px); } #viz { flex: 1; background: linear-gradient(180deg, rgba(255,255,255,0.02), transparent); border-radius: 8px; position: relative; overflow: hidden; } #glcanvas { width: 100%; height: 100%; display: block; } #sidebar { width: 360px; background: rgba(255,255,255,0.02); border-radius: 8px; padding: 12px; overflow: auto; } #objectsList { list-style: none; padding: 0; margin: 0; display: flex; flex-direction: column; gap: 8px; } .obj-item { display: flex; justify-content: space-between; align-items: center; padding: 8px; background: rgba(255,255,255,0.01); border-radius: 6px; font-size: 14px; } .obj-item button { margin-left: 8px; background: transparent; color: var(--muted); border: 1px solid rgba(255,255,255,0.03); padding: 6px 8px; border-radius: 6px; } #pairs { margin-top: 8px; font-size: 13px; color: var(--muted); } footer { padding: 8px 12px; font-size: 12px; color: var(--muted); border-top: 1px solid rgba(255,255,255,0.02); } const API = '/api/objects'; const AU_KM = 149597870.7; // Basic color palette const COLORS = [ 0xff7f50, 0x7fffd4, 0xffd700, 0x87cefa, 0xda70d6, 0x98fb98, 0xff69b4, 0x40e0d0 ]; // UI elements const nameInput = document.getElementById('nameInput'); const addBtn = document.getElementById('addBtn'); const clearBtn = document.getElementById('clearBtn'); const objectsListEl = document.getElementById('objectsList'); const pairsEl = document.getElementById('pairs'); addBtn.addEventListener('click', async () => { const name = nameInput.value.trim(); if (!name) return; addBtn.disabled = true; try { const res = await fetch(API, { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ name }) }); const data = await res.json(); if (!res.ok) { alert('Error: ' + (data.error || JSON.stringify(data))); } else { nameInput.value = ''; await refresh(); } } catch (err) { alert('Network error: ' + err); } finally { addBtn.disabled = false; } }); clearBtn.addEventListener('click', async () => { // Remove all tracked objects by deleting each const objs = await fetch(API).then(r => r.json()).then(d => d.objects || []); await Promise.all(objs.map(o => fetch(API + '/' + o.id, { method: 'DELETE' }))); await refresh(); }); // Three.js setup const canvas = document.getElementById('glcanvas'); const renderer = new THREE.WebGLRenderer({ canvas, antialias: true }); const scene = new THREE.Scene(); const camera = new THREE.PerspectiveCamera(60, 2, 0.001, 1e7); camera.position.set(0, 5, 12); const ambient = new THREE.AmbientLight(0xffffff, 0.6); scene.add(ambient); const dir = new THREE.DirectionalLight(0xffffff, 0.8); dir.position.set(5, 10, 7); scene.add(dir); // Sun const sunMat = new THREE.MeshBasicMaterial({ color: 0xffd27f }); const sunGeo = new THREE.SphereGeometry(0.25, 24, 24); const sunMesh = new THREE.Mesh(sunGeo, sunMat); scene.add(sunMesh); const objectsGroup = new THREE.Group(); scene.add(objectsGroup); // map id -> {mesh, labelEl, color} const tracked = new Map(); function resizeRendererToDisplaySize(renderer) { const canvas = renderer.domElement; const width = canvas.clientWidth; const height = canvas.clientHeight; const needResize = canvas.width !== width || canvas.height !== height; if (needResize) { renderer.setSize(width, height, false); } return needResize; } function createOrUpdateObjectMesh(id, name, posAU, index) { let entry = tracked.get(id); if (!entry) { const color = COLORS[tracked.size % COLORS.length]; const mat = new THREE.MeshStandardMaterial({ color }); const geo = new THREE.SphereGeometry(0.05, 16, 16); const mesh = new THREE.Mesh(geo, mat); objectsGroup.add(mesh); entry = { mesh, name, color }; tracked.set(id, entry); } // Scale positions so AU ~ 1 unit; we use direct AU units. For better visibility, optionally scale up/down entry.mesh.position.set(posAU.x, posAU.y, posAU.z); entry.name = name; return entry; } function removeObjectMesh(id) { const entry = tracked.get(id); if (!entry) return; scene.remove(entry.mesh); if (entry.mesh.geometry) entry.mesh.geometry.dispose(); if (entry.mesh.material) entry.mesh.material.dispose(); tracked.delete(id); } // UI list rendering function renderObjectsList(objects) { objectsListEl.innerHTML = ''; objects.forEach((o, idx) => { const li = document.createElement('li'); li.className = 'obj-item'; li.innerHTML = `

${o.name}

x:${o.position.x.toFixed(3)} AU y:${o.position.y.toFixed(3)} AU z:${o.position.z.toFixed(3)} AU

`; const removeBtn = document.createElement('button'); removeBtn.textContent = 'Remove'; removeBtn.addEventListener('click', async () => { await fetch(API + '/' + o.id, { method: 'DELETE' }); await refresh(); }); li.appendChild(removeBtn); objectsListEl.appendChild(li); }); } function renderPairs(pairs) { pairsEl.innerHTML = ''; if (!pairs || pairs.length === 0) { pairsEl.textContent = 'No pairs'; return; } pairs.forEach(p => { const div = document.createElement('div'); div.textContent = `${p.a} ↔ ${p.b}: ${Number(p.distance_km).toLocaleString(undefined, { maximumFractionDigits: 0 })} km`; pairsEl.appendChild(div); }); } // Fetch and refresh state, update 3D async function refresh() { try { const res = await fetch(API); const data = await res.json(); const list = data.objects || []; // Sync meshes const presentIds = new Set(); list.forEach((o, idx) => { presentIds.add(o.id); createOrUpdateObjectMesh(o.id, o.name, o.position, idx); }); // Remove meshes no longer present Array.from(tracked.keys()).forEach(id => { if (!presentIds.has(id)) removeObjectMesh(id); }); renderObjectsList(list); renderPairs(data.pairs || []); } catch (err) { console.error('refresh error', err); } } // Animation loop function animate() { requestAnimationFrame(animate); const needResize = resizeRendererToDisplaySize(renderer); if (needResize) { const canvas = renderer.domElement; camera.aspect = canvas.clientWidth / canvas.clientHeight; camera.updateProjectionMatrix(); } // Rotate group slowly for visual effect objectsGroup.rotation.y += 0.0008; renderer.render(scene, camera); } // Start async function start() { // fit canvas to container const container = document.getElementById('viz'); canvas.width = container.clientWidth; canvas.height = container.clientHeight; // Camera framing camera.position.set(0.5, 0.5, 2.5); camera.lookAt(0, 0, 0); await refresh(); // Poll every 2 seconds for updated positions setInterval(refresh, 2000); animate(); } start();