[dispose13432]

My question is:

1. How often does this happen?

2. Hoe many tests did SpaceX do before the first FT launch?

Considering that most rockets don't use supercooled fuels, I would expect insane tests (they can't rely on NASA's historical data).

[ben-schaaf]

All the well known rockets use cryogenic fuel at least in their ascent stages: Space Shuttle, Saturn V, Soyuz. They certainly can't rely solely on NASA's or Russia's data, but it will/has undoutably helped.

[xorxornop]

Cryogenic fuel is not the same is supercooled; supercooled is closer to freezing than to boiling