SpaceX META Thread

27 May 2020 | 14:19 GMT
What It’s Like to Sweat the Launch of a New Spaceship - A former mission controller [me] remembers the last time the United States dared to put humans in a new type of spacecraft—and some hard-won lessons for today

spectrum.ieee.org...

And they just lost SN4, exploded a minute after a successful static test fire and massive venting. Big bang, but none of the refueling tanks went with it.

twitter.com...

On to SN5.

So if my memory serves, sn1, sn3, and now sn4 have all failed pressure tests....each destroyed save the stripped down 2

I’m not googling it but I have a moderate recall ability

-Chris

The starships are the first spacex rockets built with stainless steal. I'll bet their welding is the problem. SS is a very different beast than Al and Ti.

a reply to: anzha

It’s obviously not working....I’ve got no data to prove it but I reckon sn3 was made from sn2 which would mean every single sn has failed...miserably

It doesn’t take a rocket scientist to see this...obviously I suppose

-chris

a reply to: Christosterone

They're supposed to. They're designed to be built rapidly and tested to failure to find out where any weak points are when they build the actual ones that are designed to fly more than a hop.

originally posted by: Zaphod58
a reply to: Christosterone

They're supposed to. They're designed to be built rapidly and tested to failure to find out where any weak points are when they build the actual ones that are designed to fly more than a hop.

So then we can agree all 3/4 failed

-Chris

a reply to: Christosterone

Yes, exactly as they were supposed to.

originally posted by: anzha
I'll bet their welding is the problem. SS is a very different beast than Al and Ti.

It is, but they were repeatedly testing SN4 the last couple of days. They got five static test fires out of it and even more fueling cycles. A welding issue would have emerged sooner i think.

a reply to: Zaphod58

Well they say you are not a true rocket engineer until you blow one up

But geesh three is a little excessive …….

So they decided to try to launch Demo-2 today, but the weather is still not looking good. At 50% right now and there is a low pressure system over the atlantic in the abort area. meh

a reply to: firerescue

Each failed in different ways. It's rapid prototyping to destruction. You learn quite a bit about construction and the design that way.

a reply to: Zaphod58

exactly

Starship Mk1 prototype was destroyed during an initial pressure test. SpaceX expected this and did it more or less intentionally, at least they said as much.
Mk2 was abandoned before Mk1 failed. Mk4 was also stopped when the Starship development was consolidated in Texas.
Mk3 became SN1 and was scrapped after it failed a cryogenic pressure test.
SN2 past pressurization tests and was retired.
SN3 was destroyed due to a test configuration error. They unintentionally depressured the oxygen tank and the vehicle crumbled. Parts of it were reused in SN4.
SN4 past pressure tests and completed five static fire tests before it blew up. Cause is still unknown, but it may very well be a ground equipment failure, not a design issue.

So they are clearly making progress. Do they make mistakes? Yes, the loss of SN3 was just stupid and avoidable, and arguably set the program back, say two or three... weeks.
And that's just it, so what if they are building these water towers on steroids in less then optimal conditions. As long as they keep improving, don't kill anybody, and keep building another prototype in less than a month they'll get there before the end of the year. It's completely different from how anyone else does it and the process does have some drawbacks, but the payoff will be enormous.

Also, keep in mind, SpaceX still is mostly focused on Crewed Dragon. Musk has said the development of Starship is actually slowed down because most of their engineers are focussed on making sure Demo-2 goes off without a hitch.
If Demo-2 is launched successfully developments in Texas will actually speed up even more.
So it's even not entirely unreasonable to assume they launch a Starship into orbit this year. But obviously, a lot can happen between now and then.

Demo-2 is a go today, weather permitting. The 45th Weather Wing gives it a 50/50. After looking at this morning's weather balloon data I think it is a bit higher at the Cape, however there are storms off of the Carolina's that might be a concern for the booster recovery.

a reply to: jrod

Booster recovery is an option but not relevant for this mission. This is a Nasa contract, they've said they'd launch even if the knew they wouldn't be able to recover the booster due to weather.
The problem today is the abort area. If they need to abort they need to fish Dragon out of the Atlantic.
But they do have some flexibility since Dragon can be programmed to hit specific abort zones beforehand.

T-48 weather is GO atm!

First time for Demo-2

originally posted by: Zaphod58
a reply to: firerescue

Each failed in different ways. It's rapid prototyping to destruction. You learn quite a bit about construction and the design that way.

Each failed in different ways....exactly!!

Well, I hope SpaceX’s failing upward [and explosively] model doesn’t apply to a manned mission...

-Chris

a reply to: Christosterone

Not to worry, all your pompous pearl-clutching and poo-pooing failing-downward-model applies to you — SpaceX: 1; you: 0.

Props to all involved in today’s successful launch 🚀

a reply to: Christosterone

You don't get it. They're supposed to fail. The fact that each failed in different ways is what you want to happen. None of these were ever meant to fly more than a couple hundred feet, if they left the ground at all. That's the entire point of rapid prototyping to destruction. It's how you quickly find flaws with your system.

Thát was one bleep of a launch. I even got the misses to watch, and she was like, wow. (Normaly she does ewwww to anything spacy.)

That was a giant leap for Misseskind!