| Primary satellite | Secondary satellite |
| Name | Vanguard 2 | COSMOS 2251 DEB |
| Spacetrack catalog number | 11 | 40223 |
| Radar cross section | medium | small |
| Epoch of two-line elements (UTC) | 2024 Sep 19 15:23 | 2024 Sep 19 23:57 |
| Time of closest approach (UTC) | 2023 Jun 14 08:36:24.131 |
| Minimum distance | 7538.086 km |
| Height difference | 257.549 km |
| Relative speed | 14.261 km/s |
| Angle between velocity vectors | 136° |
| Geographic position | 33.0°S, 154.5°E |
| Height | 651 km |
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