| Time (UTC) | Countdown | Updates |
| --- | --- | ---|
| | T-00:05:00 | Range and weather are go. |
| | T-00:06:00 | coverage has begun. |
| | T-00:25:00 | ♫ ♫ ♫ ♫ ♫ ♫ ♫ Webcast is up!
| | T-00:30:00 | 30 minutes to launch. Weather is still 80% go.
| | T-00:35:00 | Sunrise |
| | T-00:45:00 | LOX loading has begun |
| 10:10 April 30 | T-01:05:00 | This could possibly be the first Block 4 flight! |
| 10:05 April 30 | T-01:10:00 | RP-1 loading has begun |
| 10:00 April 30 | T-01:00:00 | 1 hour to launch window |
| 09:20 April 30 | T-01:40:00 | USAF reports that launch has slipped 15min into window |
| 09:00 April 30 | T-02:00:00 | 2 hours to launch! |
| 08:20 April 30 | T-02:40:00 | Weather is 80% GO at this time |
| 00:00 April 30 | T-11:00:00 | --- |
| 20:50 April 29 | T-14:10:00 | Launch thread goes live |