| Primary satellite | Secondary satellite |
| Name | ASTEX 1 | COSMOS 2251 DEB |
| Spacetrack catalog number | 5560 | 33938 |
| Radar cross section | large | small |
| Epoch of two-line elements (UTC) | 2024 Dec 22 14:21 | 2024 Dec 22 21:39 |
| Time of closest approach (UTC) | 2024 Dec 25 06:37:46.833 |
| Minimum distance | 2.909 km |
| Height difference | -2.511 km |
| Relative speed | 13.731 km/s |
| Angle between velocity vectors | 134° |
| Geographic position | 70.4°S, 176.5°W |
| Height | 764 km |
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