| Primary satellite | Secondary satellite |
| Name | Cosmos 858 Rocket | FENGYUN 1C DEB |
| Spacetrack catalog number | 9444 | 30831 |
| Radar cross section | large | small |
| Epoch of two-line elements (UTC) | 2021 Jan 20 04:37 | 2021 Jan 18 18:20 |
| Time of closest approach (UTC) | 2020 Nov 30 14:15:58.894 |
| Minimum distance | 13.091 km |
| Height difference | 1.565 km |
| Relative speed | 14.523 km/s |
| Angle between velocity vectors | 153° |
| Geographic position | 70.8°S, 85.6°E |
| Height | 788 km |
|