| Primary satellite | Secondary satellite |
| Name | Cosmos 1821 Rocket | SL-16 DEB |
| Spacetrack catalog number | 17526 | 39726 |
| Radar cross section | large | small |
| Epoch of two-line elements (UTC) | 2021 Jan 15 14:48 | 2021 Jan 15 17:05 |
| Time of closest approach (UTC) | 2020 Nov 30 17:35:24.870 |
| Minimum distance | 1.371 km |
| Height difference | 0.152 km |
| Relative speed | 14.138 km/s |
| Angle between velocity vectors | 150° |
| Geographic position | 29.5°S, 26.8°E |
| Height | 1015 km |
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