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Starship Prototype Unveiled

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Re: Starship Prototype Unveiled

#131

Post by maccam94 »

cryptoz wrote: post #44
DanCarvajal wrote: post #33

Earlier quoted context omitted.

Starship could have Falcon Heavy level of delays (which I think it will) and still beat SLS.

FH was 5 years+ behind schedule before it was built and launched. Starship already has multiple constructions going on, with multiple prototypes to test and multiple full-size vehicles planned quickly. In 2011, FH was supposed to have "arrival at launch site" by 2H 2012. It first launched in 2018 (after arriving at launch site in 2018 not 2012). The same level of delay would mean the first Starship does not reach orb…

FH got delayed because they kept improving the F9, so they didn't need the FH for many of the original target payloads. Some of the delay was due to technical issues, but changes to the F9 were significant over that time period. Starship has no dependencies on the Falcon stack.

Re: Starship Prototype Unveiled

#132

Post by mrfusion »

pmoriarty wrote: post #75
martythemaniak wrote: post #21

That was a very dense an informative presentation last night, but I think the main take away is that rapid reusability is a game changer. In fact, game-changer is probably an understatement, basically every intuition and rule-of-thumb we have about space launches and travel will have to be rethought. And this will be true even of SpaceX falls well short of meeting their stated targets (2020 orbit, 150t capability, mu…

"the world's launch capacity will be expanded by two orders of magnitude" How will so many more launches impact the space junk problem? From what I understand, there's already a catastrophe waiting to happen if some space junk collides with a satellite and causes a chain reaction of more space junk destroying more satellites, etc... until there's an impenetrable debris field around the earth. Will having that many mo…

Conversely it will make it cheap to launch clean up missions and to test different strategies and find the best approach.

Re: Starship Prototype Unveiled

#133

Post by davidivadavid »

vermontdevil wrote: post #124
davidivadavid wrote: post #123

Earlier quoted context omitted.

How come no one thought of using steel before?

Steel was used before for the early Atlas rocket models. But the skin was too thin and collapsed on its own weight. You can see YouTube videos of this.

Did any new process/invention make it viable to use steel today that wasn't available before?

Re: Starship Prototype Unveiled

#134

Post by antod »

hinkley wrote: post #108
drchewbacca wrote: post #89

I am so amazed by the genius of making it out of steel. It's just so completely counter intuitive but has accelerated their progress so much. If they told you the stats of the material, better strength at cryo tempertures meaning mass reduction, higher melting point meaning minimal heat shielding and great thermal conductivity it would be easy to imagine it was some new super composite. Then your head explodes when t…

Didn't the Russians use a lot of steel in their Space Age era rockets? It always seemed to me like we went too high tech too quickly and the Soviets were practical to a fault, and the truth should be something in between.

From memory the MiG-25 interceptor had quite a lot of steel in it for thermal reasons. Titanium was too difficult to work with for them at that time (or something).

Re: Starship Prototype Unveiled

#135

Post by x3n0ph3n3 »

_Microft wrote: post #40
allannienhuis wrote: post #34

Earlier quoted context omitted.

the material isn't the question, it's why they had to weld it together in a patchwork quilt. Elon talked about the next version would simply have rolled coils with a single seam weld (although the cylinders would have to be welded together too), which would be better structurally and cosmetically, and likely lower cost of production. Sounds like they just didn't have the rolling machines to do the job, or perhaps the…

It will reduce the length of the welds (for the hull) quite a bit. The number of rings is roughly 35 for Starship, with about ten vertical seams each. For easier thinking, line the vertical seams up and you see that this gives 50m length per vertical seam from bottom to top of Starship. So there are a total of 500m for that. 35 rings with ~28m circumference add up to about 1km of seams between them. Now if they can u…

The way I understood the presenation, they plan to use a single piece of steal, bent at an angle and rolled around (think one of those Pillsbury roll cans) with a single weld seem, in a giant helix.

Re: Starship Prototype Unveiled

#136

Post by Paperweight »

afterburner wrote: post #110
drchewbacca wrote: post #89

I am so amazed by the genius of making it out of steel. It's just so completely counter intuitive but has accelerated their progress so much. If they told you the stats of the material, better strength at cryo tempertures meaning mass reduction, higher melting point meaning minimal heat shielding and great thermal conductivity it would be easy to imagine it was some new super composite. Then your head explodes when t…

> Imo Elon is starting to get into contention for greatest engineer of all time. I don't know man, did he design it himself?

Meta-engineer? Engineering executive? At least he's trying to advance humanity instead of squandering it all on yachts like almost all the rest of the world's billionaires.

Re: Starship Prototype Unveiled

#137

Post by anonytrary »

mlindner wrote: post #47

Some quotes from Elon Musk in the presentation: "If the schedule is long it's wrong, if it's tight its right." "The best part is no part." "The best process is no process." This really is different compared to how the space industry has done things in the past.

Some statements are so absolute that they cannot possibly be correct.

> "The best part is no part."

Simple design is better because less moving parts means less complexity.

> "The best process is no process."

No single process is a panacea for all situations, so strictly adhering to a process will eventually cripple you. The best process is the ability to quickly change your process when it is necessary.

Re: Starship Prototype Unveiled

#138

Post by aaronblohowiak »

Klathmon wrote: post #36
codeulike wrote: post #27

Earlier quoted context omitted.

Here's a Wired article about the raptor engine - it's "a full-flow staged combustion engine, only the third engine in history to employ this technique ... The previous two attempts at such an engine, one in the Soviet Union in the 1960s and another in the US in the early 2000s, never made it beyond testing." https://www.wired.co.uk/article/spacex-raptor-engine-starshi...

And if you want to get a lot more detail on what makes a "full flow staged combustion engine" so special, this article from Everyday Astronaut goes into some amazing detail on this and many other engines. https://everydayastronaut.com/raptor-engine/

This was AMaZING. Exactly the kind of content I want to consume on HN

Re: Starship Prototype Unveiled

#139

Post by SECProto »

computerex wrote: post #80

I just want to point out that SpaceX has not yet successfully put a human in LEO. The moon seems well beyond their technical capabilites at the moment and Mars seems like a fools dream at this point in time.

> I just want to point out that SpaceX has not yet successfully put a human in LEO.

Does this preclude them from doing so in the future? They certainly will within the next year or so (crew dragon).

The moon has been out of reach of humans for 47-ish years mostly because we haven't had the orbital capacity to get there. Humanity has not had a super-heavy-lift launcher since the Saturn V (excluding the Shuttle and Energia, as they're mostly launching inert structural mass, rather than the fuel necessary to get elsewhere and back).

Certainly it's challenging, and their timelines are incredibly optimistic, but I've been watching SpaceX for about a decade, and they generally do the things they claim they will (on delayed timelines).

Re: Starship Prototype Unveiled

#140

Post by walrus01 »

avar wrote: post #68
hoorayimhelping wrote: post #20

380s for ISP for the Raptor vacuum engine seems durn good, considering the tradeoffs between hydrogen and methane. The most efficient engines we've flown, the RL-10 [0] (used on the Delta IV and Atlas rockets as part of the Centaur Upper Stage) and the RS-25 [1], (the Space Shuttle Main Engine) get around 450-460s for their specific impulse. These engines use liquid hydrogen and liquid oxygen. The issue with liquid h…

> This is basically how SpaceX seems to operate: rather than optimizing a single part of the system (like trying to get the most efficient engine), they try to optimize from a systems level. They're optimizing for "real" reusability, as in eventually aiming for airline-like turnarounds. None of the earlier engines you noted were reusable except the RS-25, and given how long it took to turn the Shuttle around one coul…

> and given how long it took to turn the Shuttle around one could argue it doesn't really count as "reusable" in sense SpaceX is aiming for.

Not just the time but the cost, if you take the figure of how much the space shuttle program cost, and divide it by total number of flights (including the two lethal ones), it cost somewhere between $900 million to $1.1bn every time the thing launched. It was very far from the early 1970s dream of an economically reusable spacecraft.

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