Etalon
Shape built from published dimensions and pictures; details simplified.
Turn it in 3D
Open the 3D viewer (www.spaceradar.ai).
The viewer loads when you ask: about 700 kB the first time (three.js and the model), much less after.
Pictures 4
Three-quarter view
From the side
From behind
From above
About this model
Etalon is one of the 203 3D models Space Radar made itself: a satellite, built in code from published dimensions and photographs, with no image-to-3D generator and no one else’s mesh.
Shape built from published dimensions and pictures; details simplified. It has 13,672 triangles in a 100 kB glTF file, and is 1.3 m across at full scale.
On Space Radar’s live map it is drawn for the object with NORAD catalogue number 19751, where its published orbit puts it now. Open it on the map.
Dimensions and their sources
| Measure | Value |
|---|---|
| Diameter | 1.294 m |
| Retroreflectors | 2146 |
International Laser Ranging Service (NASA-hosted), ilrs.gsfc.nasa.gov/missions/satellite_missions/current_missions/… and eta1_reflector.html, opened 2026-10-13: 'Each Etalon satellite is a 1.294 m diameter sphere. The diameter of the sphere touching the corner cube reflector (CCR) faces is 1284 mm'; 'a total of 2140 fused-quartz CCR's (304 arrays 7 CCR's each and 2 arrays 6 CCR's each) plus 6 germanium CCR's.'; 'made of aluminum-titanium alloy with an integral coefficient of diffuse reflectivity 0.7'; the distribution is 'not absolutely uniform'. NOT CITED: where any array sits, the size of a cube's face (drawn 27 mm across, six-sided), the pitch inside an array (drawn 31 mm) (read 2026-10-13)
How it was made
Built in code from published dimensions and photographs, with no image-to-3D generator and no one else’s mesh. 3D model: built by Space Radar from the published counts of Etalon's 2 146 retroreflectors.
The full record
built by this project in code (the private tool model-from-images: assemble.py, from a yaml of primitives), from the cited dimensions and the pictures under `references`; no image-to-3D model was used, and no published mesh
Where the map uses it. NORAD 19751 (COSMOS 1989, Etalon 1) and 20026 (COSMOS 2024, Etalon 2), the two Soviet laser-ranging balls in the navigation satellites' orbit. Both were the one plain ball (scene/models.js `sphere`), which is still what is drawn while this file is on its way; batch three of the model backlog
Licence note. No picture ships and none was traced: the only photograph found is not free and was looked at on the page named under `references`; the shape is this project's, under this repository's licence
References 1
What the shape was compared with. None of these pictures is in the file.
- Etalon-1 and -2, the ILRS mission pageInternational Laser Ranging Service; photograph no credit line is given, so it is not relied onThe page's text is NASA-hosted (the International Laser Ranging Service at Goddard); its photograph is NOT FREE: no credit line is given, so it is not relied on
Use it
The model is under the MIT licence: use it, change it and share it, in any project, also a paid one. Keep the credit:
Etalon 3D model by Space Radar (spaceradar.ai), MIT LicenseAny glTF 2.0 loader that reads meshopt compression (EXT_meshopt_compression) opens the file: three.js with its MeshoptDecoder, Babylon.js, model-viewer. Tools such as glTF-Transform can write an uncompressed copy.
Or embed the viewer in your page:
<iframe src="https://www.spaceradar.ai/model/?id=etalon" title="Etalon, 3D model by Space Radar" width="600" height="450" loading="lazy" style="border:0;max-width:100%"></iframe>Related models
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Shape built from published dimensions and pictures; details simplified.