Right now, ten thousand satellites are gliding above us. 10,000+ satellites. Live.
Every Starlink in the mesh, every GPS bird, the ISS, Tiangong, the full GNSS networks, the weather sentinels — drawn from the public TLE catalogs the U.S. Space Force releases through CelesTrak, propagated with the standard SGP4 algorithm.
A custom GPU-side SGP4 propagator holds every satellite smooth while you scrub time, rotate the globe, and zoom from city to constellation in one continuous gesture. Sixty frames a second on a standard phone, and up to 120 on ProMotion and M-series displays.
A second one-time unlock on iPhone and iPad: scrub the timeline from Sputnik 1 in 1957 through today. Watch the LEO shell ignite as Starlink launches start in 2019. GPS fills in through the 80s and 90s. Every constellation appears on its real birthday.
8K Earth texture with OSM map tiles at close zoom. Country borders, day/night terminator with atmospheric scattering, the Sun and Moon in their true positions every frame.
The free Mac screensaver auto-cycles smooth camera presets — LEO close-ups, the GEO ring, lunar flybys — woven through six decades of orbital history.
Two-line element sets pulled live from CelesTrak. Search any satellite by name or NORAD ID. Filter by constellation, orbit type, or altitude. Tap to track and follow.
SGP4/SDP4 propagation on the GPU, the data sources behind every satellite, the shaders that draw the atmosphere, and the accuracy numbers across platforms. Read the technical details →
A one-time purchase on iPhone and iPad opens the full mesh — nearly ten thousand satellites as a living lattice around the planet, the Starlink V2 laser cross-link topology drawn from SpaceX's published mesh design (the live operational link state is not public). Plus OneWeb, Iridium NEXT, and the commercial LEO fleets.
iOS 17+ · App Store
Download on the App Store Free on the App Store.The space age, one era at a time.
Download ZIP Extract, double-click .saver, select in System Settings.tvOS 17+ · TestFlight
TestFlight beta. Limited spots available.Coming soon · macOS 14+
Coming soon · visionOS 2+
Coming 2026
Starlink shells and low-Earth orbit satellites in real time
All orbital data is sourced from CelesTrak, which aggregates official Two-Line Element (TLE) sets published by the U.S. Space Force. Positions are calculated using the SGP4 orbital propagation algorithm.
Download the .zip file, extract it, and double-click the .saver file. macOS will prompt you to install it. Then go to System Settings → Screen Saver and select "SatRadar". Requires macOS 14+ with a Metal-capable GPU.
We try really hard — and we're only ever as good as the data we're handed. Every dot is a public Two-Line Element set that CelesTrak relays from the U.S. Space Force, run through SGP4 to get a position. SGP4 is a fast analytical propagator, not a precision tracker, and a TLE ships with no error bars: real accuracy depends on the object, its drag, recent maneuvers, and how stale the TLE is. Rule of thumb — a fresh LEO TLE (a day or two old) lands within a few kilometers of truth and drifts steadily past a week. We refresh the catalog every session. This is v1.0, built for wonder and exploration, not conjunction analysis or aiming your dish. So if you catch a satellite parked somewhere it clearly shouldn't be, that's not us being coy — it's a bug, and we'd genuinely love to hear about it. Tell us what looks off, and check our cross-platform accuracy tests for the receipts.
Yes. On first launch, the app downloads and caches TLE data locally. It will display satellites using cached data when offline, though positions will gradually become less accurate without fresh TLEs.
The trails show recent orbital paths for the four operational GNSS constellations: green for GPS, red for GLONASS, orange-amber for Galileo, and pink/red for BeiDou. Each trail shows the satellite's path over the last ~45 minutes.
All the way to 1957. Sputnik 1's launch is the earliest entry — we hand-curated its orbital parameters from the well-documented launch record, since the modern TLE format itself postdates Sputnik. Our archival TLE snapshots start in 1962 and run through the present day, pulled from real Space-Track archives.
Yes — Sputnik 1 (1957), Vanguard 1 (1958, the oldest satellite still in orbit), Yuri Gagarin's Vostok 1 (1961), Telstar 1 (1962), and the ISS (1998) are all in the catalog on the iPhone and iPad apps with the Time Travel unlock. Each appears from the year it actually launched onward.
Honestly? No. The clouds are a procedural noise texture, dressed up to look like a plausible weather day. We considered hooking up live cloud cover from NOAA, but the satellites themselves are already the live thing — piping in real cloud imagery just made the planet busier without making it better. Maybe one day, if you really want to know whether your overhead Starlink pass is going to be visible tonight.
Yes. Append ?follow=<NORAD-ID-or-name> to the viewer URL and the camera enters follow mode on that satellite at load. Prefer the NORAD ID — names move in and out of the catalog, but IDs are permanent. A few examples:
56179, AstroForge's 2023 asteroid-mining tech demo (CelesTrak catalogues it ORBASTRO-AF 1 after its OrbAstro-built bus). It dropped out of the live "active" catalog, so the link pairs ?date=2023 with ?follow= to load the era where it's still tracked62627, Inversion Space's early-2025 sun-synchronous LEO payload at ~500 km56371, Astranis' software-defined GEO comms platform62455, an Astranis-built MicroGEO flying for Anuvu's inflight-connectivity service, launched on Astranis' dedicated "From One to Many" mission (Dec 2024)62456, an Astranis MicroGEO and the first communications satellite dedicated to the Philippines, from that same dedicated launchYou can stack three more params for richer deep-links: ?date=2024-10-04 (ISO date, YYYY-MM-DD, or just YYYY) seeks the simulation clock; ?speed=100 sets the time-warp multiplier (0 = paused, negative = reverse); ?altitude=8.0 pins the camera distance in Earth-radii. Every param is client-sanitised — junk values are dropped with a console warning and the URL behaves as if the bad key was absent.
The web viewer at satradar.com and the macOS screensaver are free. The iPhone and iPad apps are free with the ISS, Tiangong, the full GNSS networks (GPS, GLONASS, Galileo, BeiDou), and the geostationary weather sentinels. Two optional one-time unlocks fund development: Unlock Starlink adds the full Starlink mesh plus OneWeb, Iridium NEXT, and the commercial LEO fleets; Time Travel opens the scrubber from Sputnik 1957 through today. No subscriptions. Family Sharing supported on both.
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