| Primary satellite | Secondary satellite |
| Name | Cosmos 858 Rocket | IRIDIUM 126 |
| Spacetrack catalog number | 9444 | 42809 |
| Radar cross section | large | large |
| Epoch of two-line elements (UTC) | 2021 Jan 20 04:37 | 2021 Jan 19 20:08 |
| Time of closest approach (UTC) | 2020 Dec 03 08:29:17.623 |
| Minimum distance | 116.894 km |
| Height difference | 3.382 km |
| Relative speed | 2.141 km/s |
| Angle between velocity vectors | 16° |
| Geographic position | 41.2°N, 95.3°E |
| Height | 781 km |
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