| Primary satellite | Secondary satellite |
| Name | Vanguard 1 | deb Delta 139 |
| Spacetrack catalog number | 5 | 12217 |
| Radar cross section | medium | small |
| Epoch of two-line elements (UTC) | 2021 Jan 22 09:10 | 2021 Jan 22 11:27 |
| Time of closest approach (UTC) | 2020 Dec 08 15:51:39.803 |
| Minimum distance | 11.996 km |
| Height difference | 2.823 km |
| Relative speed | 12.066 km/s |
| Angle between velocity vectors | 102° |
| Geographic position | 34.4°N, 176.9°W |
| Height | 813 km |
|