
Why Elon Musk is tweeting about a stainless-steel starship - kristianp
https://arstechnica.com/science/2019/01/elon-musk-is-really-really-excited-about-his-starship/
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bryanlarsen
Ars Technica has a great comment section on its space articles, be sure to
check that out too.

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tyu1000
Ars is probably the best tech site on the web.

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benj111
So the image of it in 2 pieces outside in the desert.

I have visions of rockets being constructed in clean hangars. That looks more
like some mining set up.

They wouldn't have constructed it outside, unprotected already would they?

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arethuza
"That looks more like some mining set up"

As an aside, that reminds me of the early designs for Orion ships which had to
be fairly robust and weight wasn't really an issue so they thought they'd use
naval shipbuilding techniques rather than those we normally associate with
aerospace - steel plate and rivets!

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bradgessler
I think you meant Sea Dragon, not Orion.

Link:
[https://en.wikipedia.org/wiki/Sea_Dragon_(rocket)](https://en.wikipedia.org/wiki/Sea_Dragon_\(rocket\))

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arethuza
I did mean the nuke powered ships from Project Orion:

[https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls...](https://en.wikipedia.org/wiki/Project_Orion_\(nuclear_propulsion\))

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lenkite
What are the characteristics that make stainless steel a better choice than
carbon fiber for the BFR ? Is it just tensile strength ?

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progval
> Usable strength/weight of full hard stainless at cryo is slightly better
> than carbon fiber, room temp is worse, high temp is vastly better

[https://twitter.com/elonmusk/status/1077111607564464129](https://twitter.com/elonmusk/status/1077111607564464129)

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manicdee
Also:

SS has longer service life than composites or aluminium due to being less
susceptible to fatigue. This is important on a spacecraft intended to be
reusable, and

SS is highly reflective to infrared aka heat, which is important for handling
reentry heating which is mostly radiative heating from the bowshock.

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YouKnowBetter
TL;DR

I could not find the answer directly in the article but in spotted it in the
URL: elon-musk-is-really-really-excited-about-his-starship

Edit: typo

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ricardobeat
The answer is “because SpaceX is actually building a stainless-steel starship,
with first test flights planned for March”.

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gaius
Unless they have quietly invented warp drive, no they aren’t.

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_Microft
As Scott Manley said [1] so nicely:

 _If you 're one of those people that wants to complain about this [name
'Starship'], please show that you're also complaining of Boeing StarLiner and
at Lockheed Starfighter otherwise I'll presume you're biased against Elon Musk
specifically._

[1]
[https://www.youtube.com/watch?v=XVgEKBwE2RM&t=41](https://www.youtube.com/watch?v=XVgEKBwE2RM&t=41)

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gaius
I have never heard of the Starliner and the Starfighter went out of service
before I was born but consider them both complained about too.

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ForHackernews
> No nation or company has ever built a single vehicle capable of flying
> dozens of people into space (especially deep space), landing on distant
> worlds, and then flying back to Earth.

At this risk of stating the obvious, this is still the case today. SpaceX
building a mockup in the desert does not mean they are anywhere close to
achieving this goal.

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manicdee
Once the new high pressure Raptors are working, most of that dream will be a
reality. The only things holding SpaceX back at this point are the heatshield,
the engines and Planetary Protection.

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bufferoverflow
A content-free article.

Just some ramblings of a writer about SpaceX, no new information, no answer to
the question in the title.

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unwind
Summarizing content from someone's Twitter posts so that I don't have to
actually, you know, use Twitter, is certainly valuable content from my point
of view. The bulleted list of facts about the Starship, including information
about construction materials and cooling solutions, is certainly content, too.

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verytrivial
Here's my guess: This thing, which is being assembled outdoors in the elements
by dudes on mobile cherry pickers and which has low enough build and finish
quality to not even make to as a temporary Epcot Center exhibit, is designed
to make it to some altitude, careen sideways then EXPLODE, creating a Twitter
storm and news headlines.

It exists to readjust people's expectations on how difficult the project to
get to Mars is, and _how likely it is people are going to die_ , which is
something than Elon has taken some glee in reiterating over time.

Edit: Look at the third picture here and tell me this is anything other that a
"rocket sketch" [https://www.nextbigfuture.com/2019/01/why-is-spacex-
working-...](https://www.nextbigfuture.com/2019/01/why-is-spacex-working-
around-the-clock-on-the-starship-prototype.html)

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pietjepuk88
Have you seen the grasshopper[0], which had roughly the same purpose for the
early Falcons? That hardly looked like a space vehicle, but did its job quite
well. I do very much agree it all feels a bit rushed (working during weekends
as well), and I really do wonder why they are in such a hurry.

Also, plenty of Falcons have exploded in one way or another, I'm not sure what
is new (or unexpected) about that. Things will go wrong a few times and as
Elon said in SpaceX's early days "failure is an options". It will have to go
right often enough before it gets even close to human-rated. I guess for Mars
that means going there and back again a few times (without humans).

[0]
[https://i.pinimg.com/474x/44/4f/3e/444f3e51839ba246a02bd3d29...](https://i.pinimg.com/474x/44/4f/3e/444f3e51839ba246a02bd3d298f0e390
--grasshoppers-spaceships.jpg)

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verytrivial
Yes, that Grasshopper to me looks like a carefully constructed work-in-
progress device whereas the the current one looks like a full scale mockup
with shiny wallpaper.

Maybe I overreached with an _internet_ explosion, but the silver craft just
screams "spectacle" to me, even if, due to development progress on the Raptors
it can indeed do a hop. I've been proven wrong before!

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rbanffy
They are testing a lot of things at once - it's a new metal (for rockets, at
least, it hasn't been used since the Mercury times) with new assembly
techniques and new structural demands. It'll fly with new engines that have
never flown before and, finally, the full-scale article will need to do
something nobody has ever done before - come back from orbit and do a
propulsive landing.

I dislike the active cooling part (which they'll probably start to test along
the rest with this vehicle). Everything "active" will eventually fail at the
worst possible time.

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sgc
Since the alternative is basically use of insulating tiles, which as we know
are not free of significant concerns, I have come to accept that it is
required complexity.

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rbanffy
If we had science-fiction engines, we could do a propulsive brake and skip
messing with the atmosphere altogether.

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Klathmon
Doesn't "the tyranny of the rocket equation" kind of make the idea of fully
propulsive braking systems kind of infeasible?

I know it's possible, but when you have an atmosphere not using it would be
just throwing away potential weight that you could be using for the mission at
hand.

I'm not rocket scientist, but it sounds like solving that problem using other
means (like active cooling) gives you a good amount of weight to play with
before it even begins to equal the cost of propulsive braking. And that means
you can have a lot of redundancy or can use less efficient but simpler to
operate/manufacturer/fix.

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rbanffy
It all depends on how much mass you can eject how quickly. If you have good
enough propulsion you can save on thermal shielding (and propellant mass).

And, if you have a true science-fiction-grade engine, you may not even need
propellant. ;-)

