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SpaceX test flight of Starship SN-5 [video]

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Re: SpaceX test flight of Starship SN-5 [video]

#201

Post by hnrq »

sekai wrote: post #174
kieranmaine wrote: post #147

Earlier quoted context omitted.

Could it be the case that a bright outlook leads people to overlook issues that need to be addressed. Maybe a more depressive (or realistic) disposition motivates people to enact change.

Let's look at this way, humanity needs to become multiplanetary species to prevent extinction if some sort of cataclysm happens on Earth: nuclear war; Yellowstone erupts, etc. Compared to that, any other problem seems insignificant.

I hate this argument. There is no foreseeable disaster that would make Earth less habitable than any other solar system body. Even if every nuke we have was detonated, it would still be orders of magnitude easier to survive on what remains of Earth than to live in Mars.

I'm not saying there are no existential risks at all, but being on other planets would not make us any more likely to survive to them than to simply being very well isolated on Earth (which would cost 1000x less).

Developing space technology already has all sorts of benefits and it doesn't need this poor argument in its favor.

Re: SpaceX test flight of Starship SN-5 [video]

#202

Post by wcoenen »

garmaine wrote: post #163
wcoenen wrote: post #162

Earlier quoted context omitted.

> * (or "we can put a couple humans on Mars for 3 days for $100 billion")* Is there actually a NASA proposal like that? As far as I know, orbital dynamics don't allow for this. One has to wait for a Hohmann transfer orbit window to return home.

There are faster transfer opportunities, but not 3 days. But I think he way saying 3 days of surface ops. Which is still an exaggeration. I think the NASA reference mission is 30 days?

I had a peek at the Mars Design Reference Architecture 5.0 [1], and under "trajectory options" they talk about two classes of missions.

"Opposition class missions" stay on the surface for 30 to 90 days. "Conjunction class missions" stay for 500 days or more.

That confirms the 30 days that you mentioned as a reasonable minimum.

[1] https://www.nasa.gov/pdf/373665main_NASA-SP-2009-566.pdf

Re: SpaceX test flight of Starship SN-5 [video]

#203

Post by dencodev »

thinkcontext wrote: post #53
dencodev wrote: post #30

Earlier quoted context omitted.

It's not clear to me why you need to spend so much fuel hopping around on Mars or the moon.

They are testing on a path to be able to land from orbit. Starting with short hops by prototypes that get iteratively improved is the same methodology that allowed them to be able to land their currently operating Falcon 9. They are the only one to ever achieve this. It's a big deal because everyone else builds a $100M rocket and then throws it away because it can't land. Reusable rockets have the potential to make a…

So the idea isn't to literally hop? They ultimately want to land it the same way the F9 rockets land now, and this is just a test?

Re: SpaceX test flight of Starship SN-5 [video]

#204

Post by Robotbeat »

kieranmaine wrote: post #147
nubero wrote: post #120

Earlier quoted context omitted.

I’m glad that not everyone in human history has shared your bright outlook, otherwise we would still live in caves…

Could it be the case that a bright outlook leads people to overlook issues that need to be addressed. Maybe a more depressive (or realistic) disposition motivates people to enact change.

If let free to roam intellectually without hinderment, I think such a viewpoint leads to nihilistic cynicism, not constructive action.

Which isn’t to say a tempering perspective isn’t at all helpful, I just think in the absence of all optimism (& hope), there’s no room for constructive change

To illustrate, your viewpoint seems consistent with the statement: “There can be no great progress, no humanity taking root among the stars unless led by monstrous men.”

I hope you don’t consider this a straw argument, but it’s worth considering. To believe that statement is to either believe that a “good” future is necessarily one of stagnation and extinction (whether in 1000 years or 500 million years) OR to excuse the actions of monstrous men. A pessimistic, cynical perspective means no counter-movement, no inclusive cooperative with the goal of space settlement. This isn’t exactly motivating.

(And to be clear, from the perspective of history, I do not consider Elon—definitely not perfect—to be monstrous. Neither is SpaceX the work of one man. Gwynne Shotwell is as much the leader of SpaceX as Elon is—although you wouldn’t know it by reading headlines as she doesn’t care for the spotlight—plus thousands of passionate workers (who are co-owners) who believe in this vision and many of whom would be pushing for it even without Elon’s leadership.)

Re: SpaceX test flight of Starship SN-5 [video]

#205

Post by martythemaniak »

I really love the out-in-the-open development process. It doesn't cost SpaceX anything, yet they attract lots of internet media where people set up streams, discuss progress etc. The next year should be pretty exciting as they develop things further. Starship has a number of big innovations, which are:

- the raptor engine. This was developed behind closed doors and is sort of finished. We won't see much of it, but it is the most advanced rocket engine ever made and I'm not aware of any upcoming engine that can compete with it.

- Stainless steel construction. What we're seeing with SN5 is the basic tank structure of the second stage. The hopper that flew last year was a neat demo, but SN5 was pressurized and the design is way closer to what the actual starship will end up having. The first stage tanks will also be a stretched version of these tanks, so that's why you see them focus on this so much right now.

- belly-flop landing. To land, starship will be coming downhorizontal until a few hundred meters above ground when it'll make itself vertical to land. SN5 won't have the fins and cone to perform this, but SN6 will. It might be possible to see this before the end of the year - SN6 (with 3 engines) goes up 20km, goes horizontal to burn off speed, then lands vertically.

- belly-first re-entry. Instead of a heatshielf that withstands a high temperature, Starship will burn off speed with its belly, but do it over a longer time period of time so that while the total heat is the same, the max temperature doesn't rise too much. The stainless steel can't take the temperatures ablative heatshields on capsules can. Don't know if Starhip will be able to perform this meaningfully without a booster.

- in-orbit refueling. Starship is big and heavy and basically can't get anywhere unless it's re-fueled in orbit. I don't think this has been done before, definitely gonna need 2+ starhips and boosters to show this.

- superheavy booster. This might be the simplest part of the whole system - a first stage with 31 raptor engines.

Lots of stuff coming in the next few years.

Re: SpaceX test flight of Starship SN-5 [video]

#206

Post by mschuster91 »

TomMarius wrote: post #141
zizee wrote: post #126

Earlier quoted context omitted.

In The Expanse, the main reason for complaint from earthers seems to be caused by overpopulation which leads to difficulty in obtaining realestate and the benefits that landownership brings. If UBI was implemented as in The Expanse (food, shelter, and meds are free), I would expect the population of the earth to plummet. The UBI would allow for more people to pursue learning and educating others. It has been shown th…

Was it really shown? Is there a single country that did not replace stress of violence and starvation with economic stress? Do we have at least one larger example of what would happen if the general population was rich?

> Do we have at least one larger example of what would happen if the general population was rich?

We have birth rate comparison between "first world" and "third world" countries plus migration experience studies (basically, even one generation after migration from a poor to a rich country, there is a massive drop in birth rate, and after something like 3 generations the birth rate is equal to the rest of the country).

Additionally, there is a noticeable drop in birth rates when a whole country gets richer.

Re: SpaceX test flight of Starship SN-5 [video]

#207

Post by TomMarius »

ncmncm wrote: post #154
jkn wrote: post #127

Earlier quoted context omitted.

Star Trek's society is collectivist (as all societies are, to a degree), but is it authoritarian? I suspect that summarizing collectivism as authoritarian is like summarizing libertarianism as selfish: they go well together, but you can also get one without the other. I don't know Star Trek very well, but as a utopia I guess they imagine a form of collectivism that largely preserves individual freedom? Of course most…

Anything said about libertarianism is necessarily hypothetical, because it has never happened. If it ever did, it would instantly dissolve into something certain to be very unpleasant for almost everyone.

It happened in the United States before the first world war, and continued for a few decades after that. Pretty long time to be called "immediately". While it was unpleasant from our current POV, it was way better than anything else at that time, and didn't end because it dissolved, but because the world wars needed funding.

Re: SpaceX test flight of Starship SN-5 [video]

#208

Post by dgritsko »

martythemaniak wrote: post #205

I really love the out-in-the-open development process. It doesn't cost SpaceX anything, yet they attract lots of internet media where people set up streams, discuss progress etc. The next year should be pretty exciting as they develop things further. Starship has a number of big innovations, which are: - the raptor engine. This was developed behind closed doors and is sort of finished. We won't see much of it, but it…

> the most advanced rocket engine ever made

Would love to learn more about this, can you expand? What makes Raptor so unique?

Re: SpaceX test flight of Starship SN-5 [video]

#209

Post by mschuster91 »

ecpottinger wrote: post #99
rbanffy wrote: post #82

Earlier quoted context omitted.

The DC-X still manages to look modern next to it. Had it succeeded, it'd have done something not even SpaceX is doing, which is a fully reusable single-stage-to-orbit craft. I don't think we have the advanced materials for that.

I think the Delta-X could have done the job, what went wrong was letting NASA taking control of it. Remember these are also the people who went with segmented solid fuel boosters, these were the people who thought the VentureStar with three new techs that all had to work at the same time but rejected the designs that did not need as much new tech, these are the people who let the SLS design go forward. The Delta-X wa…

The Wikipedia article on DC-X is interesting.

> In a post-accident report, NASA's Brand Commission blamed the accident on a burnt-out field crew who had been operating under on-again/off-again funding and constant threats of outright cancellation.

That is the reason why SpaceX is so much more efficient and revolutionary, compared to what Boeing/ULA on US side and EADS/Ariane on EU are doing - they are cutting politics out of the equation and with it, a whole boatload of issues.

Re: SpaceX test flight of Starship SN-5 [video]

#210

Post by codeulike »

dgritsko wrote: post #208
martythemaniak wrote: post #205

I really love the out-in-the-open development process. It doesn't cost SpaceX anything, yet they attract lots of internet media where people set up streams, discuss progress etc. The next year should be pretty exciting as they develop things further. Starship has a number of big innovations, which are: - the raptor engine. This was developed behind closed doors and is sort of finished. We won't see much of it, but it…

> the most advanced rocket engine ever made Would love to learn more about this, can you expand? What makes Raptor so unique?

Full flow staged combustion cycle, never been flown* before, explained here:

https://everydayastronaut.com/raptor-engine/

* The Russians built one in the 60s but it never got past static fire tests

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