Predicting Flight 12 date from average times between milestones and launch
I've been crunching numbers on how long it has taken between milestones and launch. For example: Block 2 took an average of 27 days from first Ship Static Fire to launch. So if we use those timelines as a guide, can we predict Flight 12 launch date?
I looked at a lot of metrics. First segment being spotted, first ring segments stacked, stacking complete, first Static Fire etc. The stacking based milestones had huge variations in time until launch and aren't a very reliable metric, the Cryotest and Static Fire tests had much lower variations between timelines.
Here are the stats on days between each milestone and launch for Block 2.
| Milestone | Min | Average | Max | STD |
|---|---|---|---|---|
| Booste First Cryo | 69 | 117 | 179 | 56 |
| Booster Last Cryo | 68 | 115 | 175 | 55 |
| Booster First SP/SF | 25 | 47 | 82 | 22 |
| Booster Last SF | 25 | 47 | 81 | 22 |
| Ship First Cryo | 48 | 73 | 88 | 15 |
| Ship Last Cryo | 48 | 73 | 88 | 15 |
| Ship First SP/SF | 22 | 27 | 35 | 5 |
| Ship Last SF | 5 | 18 | 31 | 10 |
The milestone with the lowest variation is the time between Wet Dress Rehearsal and Launch, an average of 4 days +/- 2 days. But it doesn't take a rocket scientist to predict a launch will probably happen 2~6 days after the Wet Dress Rehearsal.
So what does this look like for Flight 12? I've given a spread of dates based on how wide the margin of error is.
There's an asterisk on the Booster Last Static Fire because it's assuming they don't do another one tomorrow. It's a lot easier to spot the first static fire than it is to spot the last one. And the Ship Last Static Fire has another asterisk that it's predicting the date, the last SF is usually a week after the first one. So those dates should be taken with a pinch of salt.
This prediction is clearer to see as a timeline. Darker colours indicate the middle of the prediction, lighter colours further from the average and less likely to be on those dates.
Based on Booster testing it could be late May / Early June. Based on Ship testing it's looking more like mid-May. The Booster First Static Fire is a bit of an outlier because they tested it early without all engines, which was also a test of the launch pad deluge systems. So ignoring that item, it's looking like mid-late may.
There is one huge caveat over all of this that we're looking at the statistics for how long it took Block 2 to go from each milestone to launch. On the one hand we can expect SpaceX to refine their procedures and move faster with time but on the gripping hand this is the first Block 3 stack with new engines, new stage designs and a new pad. So they might need to take longer than they did with Block 2.
So my money is on mid-late May. I know some people are still hoping for an April launch but I think that's too optimistic.