| Primary satellite | Secondary satellite |
| Name | Vanguard 3 | COSMOS 2251 DEB |
| Spacetrack catalog number | 20 | 38001 |
| Radar cross section | medium | small |
| Epoch of two-line elements (UTC) | 2024 Dec 22 11:34 | 2024 Dec 19 14:25 |
| Time of closest approach (UTC) | 2024 Dec 24 13:27:40.663 |
| Minimum distance | 2.930 km |
| Height difference | 0.434 km |
| Relative speed | 7.805 km/s |
| Angle between velocity vectors | 60° |
| Geographic position | 31.6°N, 179.7°W |
| Height | 620 km |
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