| Primary satellite | Secondary satellite |
| Name | Cosmos 858 Rocket | Cosmos 841 Rocket |
| Spacetrack catalog number | 9444 | 9023 |
| Radar cross section | large | large |
| Epoch of two-line elements (UTC) | 2021 Jan 24 10:28 | 2021 Jan 24 12:39 |
| Time of closest approach (UTC) | 2020 Nov 30 04:31:12.244 |
| Minimum distance | 3.984 km |
| Height difference | 2.907 km |
| Relative speed | 13.935 km/s |
| Angle between velocity vectors | 138° |
| Geographic position | 40.5°S, 15.9°W |
| Height | 771 km |
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