| Primary satellite | Secondary satellite |
| Name | Vanguard 1 | deb Kosmos-397 |
| Spacetrack catalog number | 5 | 5103 |
| Radar cross section | medium | small |
| Epoch of two-line elements (UTC) | 2021 Jan 16 09:33 | 2021 Jan 16 07:19 |
| Time of closest approach (UTC) | 2020 Nov 29 04:02:01.145 |
| Minimum distance | 1335.242 km |
| Height difference | -55.866 km |
| Relative speed | 5.162 km/s |
| Angle between velocity vectors | 39° |
| Geographic position | 26.7°N, 0.9°W |
| Height | 901 km |
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