| Primary satellite | Secondary satellite |
| Name | Cosmos 1891 Rocket | FENGYUN 1C DEB |
| Spacetrack catalog number | 18403 | 30543 |
| Radar cross section | large | small |
| Epoch of two-line elements (UTC) | 2021 Jan 17 20:38 | 2021 Jan 17 20:31 |
| Time of closest approach (UTC) | 2020 Dec 03 22:05:15.687 |
| Minimum distance | 25.909 km |
| Height difference | 1.090 km |
| Relative speed | 13.671 km/s |
| Angle between velocity vectors | 136° |
| Geographic position | 81.2°S, 57.6°E |
| Height | 964 km |
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