| Primary satellite | Secondary satellite |
| Name | Cosmos 1891 Rocket | FENGYUN 1C DEB |
| Spacetrack catalog number | 18403 | 31531 |
| Radar cross section | large | small |
| Epoch of two-line elements (UTC) | 2021 Jan 17 20:38 | 2021 Jan 16 22:15 |
| Time of closest approach (UTC) | 2020 Dec 01 08:08:02.348 |
| Minimum distance | 6.827 km |
| Height difference | -4.303 km |
| Relative speed | 14.523 km/s |
| Angle between velocity vectors | 172° |
| Geographic position | 77.3°N, 71.6°E |
| Height | 1032 km |
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