| Primary satellite | Secondary satellite |
| Name | Cosmos 1125 Rocket | FORMOSAT 3E |
| Spacetrack catalog number | 11511 | 29051 |
| Radar cross section | large | medium |
| Epoch of two-line elements (UTC) | 2021 Jan 20 12:05 | 2021 Jan 20 04:17 |
| Time of closest approach (UTC) | 2020 Dec 08 19:21:31.016 |
| Minimum distance | 21.057 km |
| Height difference | -2.267 km |
| Relative speed | 4.936 km/s |
| Angle between velocity vectors | 39° |
| Geographic position | 71.8°S, 11.0°E |
| Height | 806 km |
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