Counting frames on YouTube, I get about 0.3s for the blast front to reach the top of the 600ft towers. That gives an estimate of around 600 tons TNT so definitely nowhere near all the fuel exploding.

▲

17 minutes ago | parent | next [-]

[deleted]

▲

debatem1 13 hours ago | parent | prev [-]

how did you compute that?

▲

xoa 13 hours ago | parent | next [-]

Sedov-Taylor-Rayleigh blast equation, though this video isn't high enough frame rate to more than ballpark it I think. Tower is ~180m high, so 0.2 sec would be a bit over 1 kiloton instead? But definitely not remotely 13 kt. Still serious of course, when SpaceX suffered launch complex damage during some of its incidents it took a solid 6-12 months to fix.

Everyone can be glad though that no hypergolics are involved at least!

▲

generuso 12 hours ago | parent [-]

You are talking about the energy of the blast. In my comment I was talking about the heat output. From the followup comments it seems I have not made it sufficiently clear.

The energy of the detonation wave in rocket explosions is typically 1-2% of the energy in the fuel, at least that is the ballpark of what people use for estimating the effects of mishaps.

We also do not know if the tanks were fully filled -- it the past, rocket companies have called 10 second static fire tests a "full duration static fire test." We will probably find out later what it actually was meant to be.

▲

catlikesshrimp 10 hours ago | parent [-]

About the couple of times you have said "fully filled", is that a specific industry or engineering slang or term?

	▲	generuso 8 hours ago \| parent [-]
		Maybe it was a bit too colloquial. I am not sure if this is very important. A formal term would have been "full propellant load." The phrase "fill level" is also used in NASA documents. The question was whether during this test the stage was loaded with the same amount of fuel as for an actual flight, or only a small fraction of that.

▲

gjrq 13 hours ago | parent | prev [-]

The estimate is roughly E = rho*R^5/t^2 with rho the density of air: https://en.wikipedia.org/wiki/Taylor%E2%80%93von_Neumann%E2%...