Orbital elements of USA 21
| Launched | 11 February 1987 |
| Flight ended | – |
| Launch site | Air Force Western Test Range, California, USA |
| Owner | United States |
| NORAD ID | 17506 |
| Date fetched |
Epoch osculation |
Inc. [°] |
Ecc. | RA asc node [hr] |
Arg Peri. [°] |
Mean anom [°] |
Mean motion [rev/day] |
Abs. mag |
| Date fetched |
Epoch osculation |
Inc. [°] |
Ecc. | RA asc node [hr] |
Arg Peri. [°] |
Mean anom [°] |
Mean motion [rev/day] |
Abs. mag |
| 2025 Dec 12 18:57 | 2025 Dec 09 02:58:09 | 62.9268 | 0.73104 | 18.8661 | 277.6188 | 12.3294 | 2.01366 | – |