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Comment by mhandley | Hacker News Reader

I'm really interested to see the hole it dug under the launch mount. The NASA SpaceFlight van took a direct hit from a fast moving chunk of concrete.

https://twitter.com/JerryPikePhoto/status/164905272269878477...

https://twitter.com/LabPadre/status/1649053476276797440

Edit: it really did dig a crater (this was flat concrete under the pad before):

https://twitter.com/LabPadre/status/1649062784167030785

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I wonder if this was expected or not. This video immediately comes to mind:

https://www.youtube.com/watch?v=gMbUeO4iGhY (Why SpaceX Cares about Concrete)

This probably explains why some of the engines didn't make it off the pad. That is some incredible damage.

Depends on what you mean by "expected." It was absolutely not supposed to happen, although a lot of people in the industry have been shouting "we have flame trenches for a reason!"

They didn't want it to happen, but they definitely knew it was a strong possibility.

I have done work for NASA on this problem through SBIRs. The risks have been known for a long time, and to my team the extent of the damage was not surprising. NASA/SpaceX just don't have the computational tools to assess these types of risks at this time.

Why dig a flame trench if you can have your test article make one for you. Efficiency!

When I dig, I only dig with super massive rockets.

The liftoff video at https://twitter.com/SpaceX/status/1649097087248891904 shows some clear debris hitting the ocean.

NSF on their stream did talk that this is the only launch that will be done without water system - my understanding is that it would be used during launch to reduce damage to the pad.

Yes, they have a water deluge system, but that might not be enough, and they also need a flame diverter.

Needing to make a big flame trench and deluge system might be the big takeaway from this flight. I'm not happy at the construction delays that'll entail but it that's what it takes for enough engines to get through liftoff it's what needs to be done.

From what I understand that was already planned - this was only launch without it.

This video filmed near the pad shows the huge chunks of debris from the pad hitting everything nearby (cars, cameras, etc) and is quite spectacular.

https://www.youtube.com/watch?v=thA8jlgcJ-8

https://twitter.com/unrocket/status/1649425500526329863

Better view of the hole and damage to the launch mount

If I'm calculating correctly from the frame rate, the lump of concrete that hit the van was doing about 330 mph after the impact. I couldn't find a pair of frames to compare before impact.

Its trying to get to the moon one way or another

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