totm nov 2023 SpaceX Discussion Thread

[darthgently]

28 minutes ago, sevenperforce said:

Or maybe boil off in space is much worse than previously thought. That's the unsettling possibility.

Depot maybe needs a JWST style multilayer shade.   Maybe fewer layers.  Like maybe an "insulation" starship that permanently docks to the sunny side of the center of the depot with tankers docking on the shady side.   Deployable shade screen would put entire depot in shade.

SSS:  Shady Starship

Edited November 17, 2023 by darthgently

[darthgently]

Shady Starship tanks could be added to depot capacity if the shade screen covered those also.  Engines could be scavenged for on orbit replacement of failed engines on tanker Starships.  If an Engineer Kerbal, er, astronaut, is present

Edited November 17, 2023 by darthgently

[tater]

Keeping a depot topped off with regular, reusable flights is one thing, but I would like to see what the numbers look like with expended vehicles, and also with partially expended (land SH, toss SS). Somewhere between the ~150t reuse case, and the ≥300t expended case, presumably. If a partial reuse could get ~263t of residuals to the depot, 4 would do it assuming 1200t.

Not counting whatever boiloff is.

Edited November 17, 2023 by tater

[tater]

 

The second flight test of a fully integrated Starship is set to launch Saturday, November 18. A twenty-minute launch window opens at 7:00 a.m. CT.

 

[Geonovast]

Why only 20 minutes this time?

[CatastrophicFailure]

5 minutes ago, Geonovast said:

Why only 20 minutes this time?

So those of us getting up at zero-dark-fifty-five on a weekend to watch this can just roll over and go back to sleep when it scrubs instead of waiting for a reset. 

[KSK]

8 hours ago, tater said:

This has to happen eventually, or we as a species are dead. I'm not a Mars bro, but the capability existing to even seriously consider creating a self-sustaining colony offworld comes with existential risk mitigation.

I’m sorry but I really don’t agree with this. OK, I might agree (with heavy reservations) with that last part, but not the part in which off world colonies have to happen or we die.

The only scenario in which an off-world colony is absolutely essential to our survival as a species, is one which makes the Earth utterly uninhabitable to human beings, whilst somehow leaving the off-world colony intact.

I can think of vanishingly few naturally occurring ways for that to happen. Even if we got clobbered by a second Dinosaur Killer sized rock, I believe we would survive. It wouldn’t be pleasant, there would be a lot less of us afterwards, but I don’t believe we would go extinct.

I can think of various more or less apocalyptic ways in which we could try and wipe ourselves out but even then actually doing it is a tall order.

But assuming that we can find a scenario that does wipe out humanity on Earth, I believe the more rational response to risk mitigation is to find a way to stop the scenario from happening rather than relying on an off-world colony as a lifeboat.

An off-world colony might (heavy emphasis on the ‘might’ for at least the reason that @mikegarrison gave) provide some additional mitigation, but I don’t believe they provide sufficient extra mitigation to make them inevitable in that ‘if we don’t do this we die’ sense.

Besides,  outside of terraforming, an off-world colony is an inherently less stable situation than any settlement on Earth, simply because it would be an entirely artificial habitat that requires constant, active maintenance and, more importantly requires that its inhabitants not go out of their way to break it, start wars in it, or whatever. And, historically, indefinite periods of mutual cooperation have not been humanity’s strong suit.

In practice, if humanity-on-Earth gets wiped out, I would give off-world humanity about a century at most. The fact that the colony is then in a precarious situation might provide a temporary brake on a war breaking out, but the very precariousness of the situation would make the impact of a war far more severe.

 

[Nuke]

il catch it on youtube when i wake up.

[tater]

54 minutes ago, KSK said:

I’m sorry but I really don’t agree with this. OK, I might agree (with heavy reservations) with that last part, but not the part in which off world colonies have to happen or we die.

The only scenario in which an off-world colony is absolutely essential to our survival as a species, is one which makes the Earth utterly uninhabitable to human beings, whilst somehow leaving the off-world colony intact.

I can think of vanishingly few naturally occurring ways for that to happen. Even if we got clobbered by a second Dinosaur Killer sized rock, I believe we would survive. It wouldn’t be pleasant, there would be a lot less of us afterwards, but I don’t believe we would go extinct.

OK, strictly speaking you are correct over the time frame before the Sun goes red giant. A dino-extinction level event would not kill ALL humans, but it would very likely set us back to pre-state society level existence. Then we have some thousands of years to reinvent everything (maybe faster with all the relics left behind—but many resources also harder to get at).

I mean that humanity as a modern technological society would be over/reset for some substantial period, possibly never to return. I would prefer progress.

Over longer time frames, we have to somehow leave the solar system, or at least move to a safe spot when the Sun goes red giant

 

54 minutes ago, KSK said:

In practice, if humanity-on-Earth gets wiped out, I would give off-world humanity about a century at most. The fact that the colony is then in a precarious situation might provide a temporary brake on a war breaking out, but the very precariousness of the situation would make the impact of a war far more severe.

2 points.

1. I have said before the ability to even seriously consider offworld colonies as within current TRL (any type, mars, O'Neill, whatever) comes with a lot of risk mitigation for the ride. So saving humanity by saving Earth from the hit in the first place. Course once the tech is there, SOME people might decide to use it to try a colony.

2. A colony as a backup for humanity is entirely predicated on it being entirely self-sufficient. So before that it's not a backup, AFTER that is achieved it is a backup.

Not pretending that's happening any time soon, hence "eventually." Where "eventually" is a VERY long time frame

 

1 hour ago, CatastrophicFailure said:

So those of us getting up at zero-dark-fifty-five on a weekend to watch this can just roll over and go back to sleep when it scrubs instead of waiting for a reset. 

Meh, 6am here is when I'd be up anyway.

Edited November 18, 2023 by tater

[darthgently]

During the next glacial humans on earth will also probably be living in mostly artificial habitats everywhere but the equatorial regions.  Maybe everywhere if some billionaire cools the planet so much (I'm looking at you, Bill Gates, you wild and crazy guy) that the next glacial is colder than normal.

I say "mostly" because even off world settlements will be different than we can imagine right now.   With expanding knowledge of how biomes, physiology, and how systems work the habitats won't be entirely artificial, but hybrid.   Applying AI like AlphaFold and advancing  molecular techniques ways to adapt plant, algal, fungal, lichen, extremophiles from ocean vents, and other cellular lines to extreme situations will result in solutions we cannot now fathom.  Soil building microbes designed for martian dirt, self regenerating filtering membranes, may become normal.  Don't know unless you try

Edited November 18, 2023 by darthgently

[magnemoe]

8 hours ago, JoeSchmuckatelli said:

Yep.  Throwing a large space rock at the earth likely violates several environmental and OSHA regulations. 

Just like any other rocket except falcon 9.  And say Electron as they pick them up. 

[tater]

AI and robotics simultaneously make the need for humans to live in space for resource collection grossly less important (why use fragile meat-workers when durable metal/plastic workers will suffice), and the ability to make habitats easier.

My gut says that the SpaceX notion of sending people to Mars to build a colony is much less likely than sending robots to Mars to build said colony (some crazy/brave humans with them, perhaps), then pitch it as a fait acompli. "Move to Mars, your apartment is waiting!"

Good luck with that (like I said, I'm not a Mars bro).

[StrandedonEarth]

1 hour ago, KSK said:

The only scenario in which an off-world colony is absolutely essential to our survival as a species, is one which makes the Earth utterly uninhabitable to human beings, whilst somehow leaving the off-world colony intact.

Well, as the Sun ages it will get hotter, and eventually Earth will be too hot whereas Mars will be much more comfortable than  it is now, especially with a few to several millennia of terraforming.

As for the number of tanker flights, the tweet also says the lander is in the middle of the tanker sequence. So it certainly sounds like a refill / boost to elliptical / refill-and-go scenario. 

Yeah, I can see a real need to design/build/launch a proper propellant depot, with (PV) sunshades,  and active cooling/conditioning with radiators if necessary

9 minutes ago, tater said:

AI and robotics simultaneously make the need for humans to live in space for resource collection grossly less important (why use fragile meat-workers when durable metal/plastic workers will suffice), and the ability to make habitats easier.

My gut says that the SpaceX notion of sending people to Mars to build a colony is much less likely than sending robots to Mars to build said colony (some crazy/brave humans with them, perhaps), then pitch it as a fait acompli. "Move to Mars, your apartment is waiting!"

Good luck with that (like I said, I'm not a Mars bro).

Yeah, that’s what they’re creating Optimus Prime for. I’m sure eventually Boston Dynamics will get on board for the heavy lifting. BD could certainly use some mass production optimization. 

Edited November 18, 2023 by StrandedonEarth

[tater]

 

[SunlitZelkova]

16 hours ago, KSK said:

Tell that first part to the employees of that private enterprise.  Even, taking that article with a large pinch of salt, it's still pretty damning. And I suspect that passing the mantle to other companies isn't a long term solution to the problem.

I'm not going to rehash what I've already said on the 'A City on Mars' thread on these forums, and this is probably skirting too close to politics anyway but my answer to @SunlitZelkova's question is: Musk is insane because he's charging headlong towards a goal of dubious value without caring who gets chewed up and spat out in the process.

And now, I'll shut up in the interests of keeping this thread open.

 

I don’t like the Mars City plan either, but I wouldn’t call their work “rushing headlong” into it.

There are currently only three Starship variants- Cargo Starship, Starship HLS, and Tanker Starship. Little to no Mars development has begun. They don’t even know if the heat shield design will work in Earth EDL.

If they start putting out calls for Mars workers, or actually do their crazy 100 person ship design (which they probably can’t without having it be like a 1600s slave ship, I saw some calculations on this forum that based on the amount of space and supplies deemed necessary for one human by ESA, 17 crew is what they can do at best), I don’t see any cause for concern.

The Starship program currently has three goals- land humans on the Moon, launch satellites, and fly a billionaire and some artists around the Moon. Mars is basically just propaganda at this point. Musk might be dead in two years for all we know and Shotwell might curtail or even cancel the private Mars program for more lucrative satellite contracts. No government or corporate entity is immune to the desire for pork that comes along eventually.

[tater]

41 minutes ago, SunlitZelkova said:

The Starship program currently has three goals- land humans on the Moon, launch satellites, and fly a billionaire and some artists around the Moon. Mars is basically just propaganda at this point. Musk might be dead in two years for all we know and Shotwell might curtail or even cancel the private Mars program for more lucrative satellite contracts. No government or corporate entity is immune to the desire for pork that comes along eventually.

Mars is not propaganda. What other secret agenda is gained by pretending to go to Mars, then designing a vehicle not optimized for near term use as a result? To make cool t-shirts? He could do that without spending billions. Mars is a goal I literally think because it's cool, and it seems like a goal that many at SpaceX are fine with. I agree with all the other stuff about no way 100 people sit in that thing for months on the trip to Mars, then somehow live in it ON Mars until they build better quarters. That's just not a thing, IMO. I agree, maybe small teams and a bunch of robots, build some habs, then new people are limited by prebuilt infrastructure to handle them. In short, nothing like 1000 ships every 2.14 years is a thing, and even colonization for real not a thing with Starship—maybe Starship V 10.0 that's far, far larger?

There are no lucrative satellite contracts. The launch business will always be chump change. If the goal was money, he'd dump SpaceX and just work on tesla which will be a gajillion dollar company (and SpaceX won't).

Bottom line is that a failure to understand what SpaceX is for colors all other views people have about what they are doing. It's not about money, it will never make loads of money in any reasonable time frame (maybe someday if there is ever a real space economy, or human spaceflight becomes airline safe we can reevaluate).

[PakledHostage]

All the talk on here of Mars colonies begs pointing out that Venus is in a lot of ways more habitable than Mars... The 60 km altitude level in Venus' atmosphere has comparable pressure and temperature to Earth and an oxygen-nitrogen mix of gas would work as a lifting gas in a balloon there. It also has very Earth like gravity and much better protection from cosmic radiation than Mars.

Access to resources like metals would be a challenge, but every off-world colony faces serious challenges of one form or another. Maybe SpaceX's propulsive landing technology could be put to eventual use flying to/from cloud cities on Bespin Venus? Living in floating bubbles there would almost certainly be preferable to moisture farming on Tatooine Mars.

Edited November 18, 2023 by PakledHostage

[tater]

 

[tater]

 

[tater]

Liftoff!

 

MECO

sep

SES-1

Fairing

Landed

SECO

Nominal orbit insertion

[SunlitZelkova]

4 hours ago, tater said:

Mars is not propaganda. What other secret agenda is gained by pretending to go to Mars, then designing a vehicle not optimized for near term use as a result? To make cool t-shirts? He could do that without spending billions. Mars is a goal I literally think because it's cool, and it seems like a goal that many at SpaceX are fine with. I agree with all the other stuff about no way 100 people sit in that thing for months on the trip to Mars, then somehow live in it ON Mars until they build better quarters. That's just not a thing, IMO. I agree, maybe small teams and a bunch of robots, build some habs, then new people are limited by prebuilt infrastructure to handle them. In short, nothing like 1000 ships every 2.14 years is a thing, and even colonization for real not a thing with Starship—maybe Starship V 10.0 that's far, far larger?

What I mean when I say “propaganda” is that it is only words. There is no “Mars fund”, and no deep engineering work is going forwards right now.

Can Starship get to Mars? Yes. But it’s not it’s main purpose right now.

In a practical context, IFT-2 brings Starship no closer to Mars than Artemis I brings SLS closer to Mars.

The only difference between the two is Starship actually has the launch cadence to do a Mars mission. But the two are quite similar, with Orion CM-001 being a test vehicle in a similar manner to Ship 16 or whatever number this one is.

4 hours ago, tater said:

There are no lucrative satellite contracts. The launch business will always be chump change. If the goal was money, he'd dump SpaceX and just work on tesla which will be a gajillion dollar company (and SpaceX won't).

Bottom line is that a failure to understand what SpaceX is for colors all other views people have about what they are doing. It's not about money, it will never make loads of money in any reasonable time frame (maybe someday if there is ever a real space economy, or human spaceflight becomes airline safe we can reevaluate).

Lucrative may be the wrong word, but the way I see it is this: satellite launches make money, sending stuff to Mars doesn’t. Unless you have another company doing the Mars research and building, but none exist right now.

If there isn’t a space launch market taking advantage of Starship rapid reuse, I really have to wonder how Musk plans to fund his city.

The City is the only thing I question. With Starship ready, it would be much easier to get a NASA-run Mars “research” mission (normal expedition) funded by the government. The low cost created by something like a “Commercial Mars Crew” or “Commercial Mars Surface Services” program might make a program palatable to Congress, whereas a Mars program in the style of how SLS is being done would be too expensive.

To put it another way, I don’t doubt SpaceX will be capable of sending scientific payloads to Mars one day, and maybe crew on a government sponsored expedition, I just think Musk’s city plans are mainly talk at this point. It’s more of a “I’ll believe it when I see it” thing, compared to how I am more inclined to believe in uncrewed Martian surface delivery services.

4 hours ago, PakledHostage said:

All the talk on here of Mars colonies begs pointing out that Venus is in a lot of ways more habitable than Mars... The 60 km altitude level in Venus' atmosphere has comparable pressure and temperature to Earth and an oxygen-nitrogen mix of gas would work as a lifting gas in a balloon there. It also has very Earth like gravity and much better protection from cosmic radiation than Mars.

Access to resources like metals would be a challenge, but every off-world colony faces serious challenges of one form or another. Maybe SpaceX's propulsive landing technology could be put to eventual use flying to/from cloud cities on Bespin Venus? Living in floating bubbles there would almost certainly be preferable to moisture farming on Tatooine Mars.

I’m a big Venus colonization fan. I’m highly skeptical of the ability of humans to give birth in 1/3 G or lunar gravity, so if there are going to be colonies on a planet instead of in orbit, Venus is the place to be.

Edited November 18, 2023 by SunlitZelkova

[Ultimate Steve]

Now the question is, do I bother sleeping...

[RCgothic]

Musk's descent down the rabbit hole of public behaviour that would get any of us promptly banned from this site makes it a lot harder to enjoy SpaceX's successes and I certainly don't want him in charge of any off-world colonies.

I am looking forward to IFT2 today though, and hope it goes as planned. I'm going to take "high teens" as the number of flights required for Artemis III with a pinch of salt. It's so at odds with what we've been hearing about payload capacity, the amount of fuel lunar starship would be able to hold, and the amount of fuel calculated as necessary for the mission. 

[Jacke]

5 hours ago, PakledHostage said:

All the talk on here of Mars colonies begs pointing out that Venus is in a lot of ways more habitable than Mars...

As long as no one talks about "terraforming" Venus in any time less than 1000's of years (and then there's the problem of preventing it from going all runaway hot spot again).  If you could remove all radiation striking Venus and if Venus was a Black Body (ie. a perfect absorber and emitter of radiation), I believe it would take about ~800 years for Venus to cool to Earth's temperature.

Things would be massively tough establishing a colony on the surface of Mars.  The surface of Venus is a no-go except for uncrewed probes.

5 hours ago, PakledHostage said:

The 60 km altitude level in Venus' atmosphere has comparable pressure and temperature to Earth and an oxygen-nitrogen mix of gas would work as a lifting gas in a balloon there. It also has very Earth like gravity and much better protection from cosmic radiation than Mars.

Well, let's see if someone can establish an equivalent atmosphere floating base on Earth; I suspect they're a lot more complicated that it seems.  Especially as if it starts falling it's doomed and everyone has to fly off it pronto.  Then there's the whole problem of establishing them from orbit and taking and sending back rockets from orbit.  And as you mentioned, it would need to get near everything that isn't available in Venus's atmosphere hauled from Earth or elsewhere in the Solar System.

 

22 minutes ago, RCgothic said:

Musk's descent down the rabbit hole of public behaviour that would get any of us promptly banned from this site makes it a lot harder to enjoy SpaceX's successes and I certainly don't want him in charge of any off-world colonies.

I agree.  Even moreso, I don't think Musk should be in charge of anything.  The information is out there supporting my position.

Edited November 18, 2023 by Jacke

[Codraroll]

12 hours ago, sevenperforce said:

Or maybe boil off in space is much worse than previously thought. That's the unsettling possibility.

Two questions immediately spring to mind here.

The first is, how?  Granted, there's a vacuum in space and a lack of gravitational force and all that, but the pressure differential in a tank is "just" 1 atm more than it would be on the ground, where we've had pressurized hydrocarbon tanks for very, very long. I can't see gravity - or the lack thereof - affecting the process that much either. Sure, there's less pressure at the top of a tank in gravity, but also more at the bottom. 

And if you go down to the molecular scale, what could possibly be going on to cause excessive boil-off? Neither the tank material or the gas/liquid would be any more prone to diffusion than on the ground. Hydrocarbons are big molecules, and tank walls are made to be vapour tight. Does the tank material age faster in space than previously assumed? If so, the ISS would have been in big trouble long before now. Are valves and flanges somehow less vapour tight in space? Again, the ISS doesn't seem perturbed by it. And there have been multiple instances of small-scale spacecraft operating fine in space for years before using their engines - and hence, their fuel - without any unexpected issues.

The second is, assuming they have found out that boil-off is worse than previously thought, how did they find that out now? I mean, they haven't conducted an experimental test of large tanks filled with fuel in space yet (small tanks have been tested and found adequate for Mars trips already, as demonstrated by the multiple spacecraft that have landed there without succumbing to boil-off problems). Any calculations, simulations, or theoretical exercises they could have run to evaluate the feasibility of orbital fuel depots, surely NASA would have also run decades ago? The discovery on hitherto unknown boil-off problems would have required SpaceX to run an unprecedented research project on the subject. In that case, I presume we would have known about it earlier.

I mean, it could be that they have discovered something new, but from existing knowledge, I don't understand what or how that could be.