| Primary satellite | Secondary satellite |
| Name | Cosmos 1656 | COSMOS 2251 DEB |
| Spacetrack catalog number | 15755 | 36053 |
| Radar cross section | large | small |
| Epoch of two-line elements (UTC) | 2021 Mar 07 20:07 | 2021 Mar 06 23:41 |
| Time of closest approach (UTC) | 2021 Jan 26 08:57:00.296 |
| Minimum distance | 6.803 km |
| Height difference | -3.855 km |
| Relative speed | 13.680 km/s |
| Angle between velocity vectors | 133° |
| Geographic position | 40.9°N, 6.5°E |
| Height | 808 km |
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