| Primary satellite | Secondary satellite |
| Name | Cosmos 858 Rocket | IRIDIUM 33 DEB |
| Spacetrack catalog number | 9444 | 33966 |
| Radar cross section | large | small |
| Epoch of two-line elements (UTC) | 2021 Jan 20 04:37 | 2021 Jan 19 15:09 |
| Time of closest approach (UTC) | 2020 Dec 01 00:26:12.964 |
| Minimum distance | 14.213 km |
| Height difference | -0.356 km |
| Relative speed | 3.802 km/s |
| Angle between velocity vectors | 30° |
| Geographic position | 63.3°S, 22.6°E |
| Height | 781 km |
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