Launch, orbit & landing data:
| Launch vehicle | X-15-3 Flight Nº: 21 |
| Launch date - time | 19 Jul 1963 - 18:20 UTC (from B-52) |
| Launch site | Smith Ranch Lake |
| Airplane carier | B-52 |
| X-15 ID | 3-21-32 |
| Mass (kg) | kg |
| Mission | Crewed suborbital test flight |
| Pilot | Joseph Walker |
| Suborbital flight: | |
| High Apogee | 105.9 km |
| Max Speed | 5.969 km/h |
| Landing date - time | 19 Jul 1963 - 18:31 UTC |
| Landing location | |
| Flight duration | 11m 25s |
Walker before X-15. Photo credit: NASA