| Primary satellite | Secondary satellite |
| Name | Cosmos 858 Rocket | PEGASUS DEB |
| Spacetrack catalog number | 9444 | 39917 |
| Radar cross section | large | small |
| Epoch of two-line elements (UTC) | 2021 Jan 23 17:46 | 2021 Jan 23 17:31 |
| Time of closest approach (UTC) | 2020 Dec 03 05:45:12.931 |
| Minimum distance | 27.216 km |
| Height difference | -0.628 km |
| Relative speed | 6.433 km/s |
| Angle between velocity vectors | 51° |
| Geographic position | 73.9°S, 129.2°W |
| Height | 787 km |
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