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Comment by gcanyon | Hacker News Reader

The explosion was unexpected and (as far as I know at the moment) unexplained, but they flew the mission at the edge of the envelope, and with a variety of different materials/missing bits on purpose, to better understand where the edge is. Everything that happened (maybe even including the explosion, we'll see in the final analysis) was, as far as we know, within the plan.

The biggest can't-miss milestone was the flawless engine restart. That gives them the go-ahead to hit orbit on the next flight.

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I'd say the payload door situation is a considerable success, at least as big as the relight itself.

I saw one of the dummy satellites bump into the edge of the door on the way out.

They were testing different catapult configurations. Seems clear that one is a no-go but others looked good.

Actually existing Starlink satellites regularly bu p into each other when lobbed in benches by the Falcon 9.

They are built to tolerate that, resulting in much better launch volume and weight utilization (sats are stacked on top of each other & held in place by rods that are then released).

The Starship Starlink release demo was quite tame in comparison to that. ;-)

The deployment system was interesting, how the last one in the layer would go back then forward before releasing.

It looked like something one would cobble together from a garage opener and weld together a bunch of rebar

You should have seen the first tech demonstrator for the Raptor engine (the family that powers Starship). It was basically a water tower (built out in the desert, welded by people specialising in building water towers). But it flew, and it landed, and then it served as a lights & camera mount for the field for a few years.

Starhopper is still there, on a parking lot next to the launch site. :)

https://starship-spacex.fandom.com/wiki/Starhopper

Keep in mind the ship diameter is like 30 feet. It may not seem like that from a camera view, but that pez dispenser is pretty massive.

I wonder how many potential designs they considered. You've got the mass of the doors and structure of the ship to consider, the mass of the cargo, actuators for both, the arrangement of cargo in the ship, all of which have interconnected tradeoffs.

Also add pressure management, warping of the dispenser and ship hull & thermal expansion.

And fornlong duration missions also lubricant evaporation, possibility of vacuum welding & atomic oxygen reactions if you spend long in low Earth orbit. :)

The fun thing is that as long as you have the requirements and acceptance right, this could still be solved with a garage door opener and welded rebar :-D

Reminds me of early Google DIY rack PCs. [1]

[1] https://www.reddit.com/r/google/comments/1lf6yat/googles_fir...

The garage door opener (literal or metaphorical) is sitting at the end of 50yr of incremental refinement, albeit for a different use.

If you can spare the weight and it meets your specs and the use it close enough you'd be a fool not to use it.

> The explosion was unexpected

Is it really unexpected that an extremely hot metal pressure tank will rupture when plunged into water?

Since the ship is designed to be caught by a tower and not be plunged into water at all, it doesn't seem like this would be an issue in normal operations.

Different explosion, the one the parent comment is talking about happened earlier in reentry

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