Rakaydos
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Posts posted by Rakaydos
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Just now, GoSlash27 said:
"The response of Arctic sea ice to a warming climate includes decreases in extent, lower ice concentration, and reduced ice thickness."
Extent and thickness are currently nominal for this time of year, and concentration is not tracked because it isn't possible to quantify on a large scale.
That's the problem with all of this; even when these people have failed to ever make a correct prediction and even when they have been busted committing outright fraud, people still accept them at their word because they are the "experts"... not even pausing to look at the data themselves.
Best,
-Slashy
Yes, all the early predictions of ice melting assumed it would melt from the sunward side. That was wrong. But they're melting from the inside out, which has the same net effect.
3 minutes ago, James M said:I see no cited sources from anyone.
How about this: https://climate.nasa.gov/vital-signs/ice-sheets/
Note that it's measuring total mass, not approximation like extent or thickness.
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10 minutes ago, GoSlash27 said:
So I take that as a 'no' then.
Carry on.
Best,
-Slashy
Rakaydos,
Researchers have claimed that they are melting bit by bit, but the data shows that the northern ice sheet is nominal and the antarctic is actually thicker than average.
"Fears" and "possibilities" are certainly not invalid, but they are also not the same thing as established fact.
Best,
-Slashy
If your measurement is in "thickness" you need to look up the definition of "rotting" again. It's true that the ice sheets are not getting thinner. But they are getting hollower, having less water per volume.
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1 hour ago, GoSlash27 said:
And you "know"-know this, or "you've been told"- know this? Because here's the problem: I've been told this as well, but nobody seems to actually have the data to back it up. So far it's all been either a) the same experts who have been making incorrect predictions my entire life and then retiring and buying beachfront property or b) people who are just repeating what they've been told by these same 'experts'. So I go and look at the actual data and I'll be darned if I can see any trend whatsoever outside of the statistical noise floor, let alone one so dire that it will cause any discernable difference 18 years from now.
Are you privy to some corroborating data I haven't already seen?
Thanks,
-Slashy
Sea level rise is dependant not in any old melting ice, but melting of ice that isnt already floating in water. The largest of these masses of land bound ice are in greenland and antarctica. If both melt completely, sea levels will have risen 10m, compared to when we first started measuring these ice sheets 50 years ago.
Going back to these ice sheets in the last few years, researchers have found them in the process of melting bit by bit, "rotting" is the term I've seen. it's looking like sea level rise is a more gradual process than initially feared, but there's still the possibility of a sudden surge if a section breaks off one of the sheets and slides into the sea.
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6 minutes ago, RealKerbal3x said:
The chomper is the Starship payload bay.
Of course, this render is almost 2 years old, so the payload bay design may have changed by now.
But chomper refers specifically to the aligator style reusable fairing, as shown above. Put shuttle doors or a cargo hatch on it, that's not a "real" chomper.
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23 minutes ago, tater said:
The black structure looks like a jig. Is this the first chomper?
Chomper prototype. SpaceX never expects to get things right on the first try. (though sometimes they do anyway, and have to scrap the spares)
unless that's just a spar of the building with a nosecone-shaped curve.
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15 minutes ago, Deddly said:
I thought that was the plan
Elon had a hard lesson with the Tesla factory about relying on overautomation. Some people in the loop make things much more reliable.
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1 hour ago, Blaarkies said:
After finally picking up the Green monolith on Kerbin, I learned that they unlock tech regardless of the R&D building's level!
This means that a caveman can unlock most caveman tech nodes with Kerbin system science, then pickup the 3 Grenoliths in the Kerbin SOI and possibly obtain the Mobile Processing Lab to just farm everything else
Obviously they can chicken out of
270 by letting it unlock 3x 90 tech nodes, which was my plan all along...but now this curve ball really complicates that.
All tier 5 nodes have to be unlocked to complete the challenge im guessing, but what about the usage of T6 parts?This has come up whenever someone discovers a green monolith. T6 parts are all good, and the T6 with the improved relay antenna is considered to be prime real estate that's basically required for monolith hunting outside Kerbin SOI.
On 1/11/2021 at 12:15 AM, JAFO said:Challenge Rules:
...
Use of Green Monoliths to unlock tech nodes is allowed
for the record
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1 hour ago, GoSlash27 said:
I find this difficult to accept at face value. Has someone actually done this simulation, and if so could you please provide a link?
I'd be willing to bet that a TSTO will beat the pants off an SSTO, even with these handicaps.
Thanks,
-Slashy
I consider it more of an inditment of pre-spaceX launchers.
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1 hour ago, wumpus said:
While it takes more delta-V, you only need to accelerate a tiny fraction of the mass to your cycler. So it becomes wildly cheaper for every trip after the first (including the trip home from Mars). The best argument for not doing it during an early trip to Mars is the maintenance requirements of the ISS are so extreme that there is little hope for the thing to be operable after another trip to Earth orbit and back (granted, it wouldn't have much protection orbiting Mars either).
As far as "expendable", the only important point is that it won't ever land (even on Mars). So refuel it if you want (although assembly in LEO seems to be the only current option). Once assembled, I'd recommend nuclear or Hall thrusters to get to L2/MTO and Starship (or similar) to take your passengers to the habitat. The only big difference between a cycler and an expendable transfer unit (i.e. at best one round trip) would be that you'd rendezvous at L2 and burn the ~1000m/s to MTI while the passengers are on board.
Indeed, cyclers are great... when they're servicing planets that can provide the same enviro plant and hab volume not landed by the cycler. I'd put that about 10 years into colonization, about 20 years from now. I would say that early missions would be more focused on building up surface infrastructure, (which gets no benifit from cyclers) than on optimizing crew size. (no 100-person colony ships until there's a cycler for them to stretch their legs during the trip, and apartments waiting for them on mars)
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14 minutes ago, wumpus said:
I'd assume that for long-haul spacecraft, the volume targets should be based on submarines.
And to "help Musk", I'd suggest building habitat modules similar to ISS, firing them up on a Super Heavy Booster (plus some expendable 2nd stage) and connecting them up in orbit (right now the only technical option is alongside the ISS. That would be politically tricky.
Note that such a habitat can be reused, see the Aldrin cycler. Of course this means you also have to pay all the delta-v to get to it, so presumably you can take your "100 passengers" and with enough refuelling pay the ~13,000 m/s delta-v needed to go from sea level to Mars intercept and dock with the cycler/habitat (hope it is big enough for 100 passengers). How to return the Starship is up to you, and docking it and using it as a "Mars shuttle" makes the most sense (and don't be surprised if you need a lot of Starships to shuttle to the cycler to meet the window requirements).
Personally, I see cyclers as a late-colonization optimization. It actually takes more DV to reach the cycler orbit than to go to mars directly, and all it does is provide facilities that cannot be landed and used on mars. If you already HAVE space capacity on mars, that's fine, but in the early synods they can use all the pressurized volume they can land.
I flat disagree with the choice to use expendable upper stages to launch cycler components, though. At the very least, you want them to be refuellable "starkickers" to get the assembled cycler into it's solar orbit once completed.
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On 7/12/2021 at 4:19 AM, Dientus said:
Not saying its impossible mind you, just thinking about the useage of rocket fuel vs escape velocity given the known gravity on Kerbin, physics and speed of flying in atmosphere, and the clock on the screen that follows conventional time format of minutes and seconds as well. Given the evidence that the game gives us, it appears to be consistent with our time frames and what we see on screen happens as it would in life as if we were there.
To elaborate... Time may flow it different rates throughout the universe, hence why I won't dismiss it out of hand, but the rate that all time flows is relative and is influenced by speed and gravity. The game gives us those numbers (speed and gravity) in our standard formats so when we watch Jeb walk across the tarmac it's happening the same as if you or I walked across the tarmac in a space suit.
If we are assuming a plantlike dialation of perceved (not actual) time, then the actual gravity of kerbin is significantly lower than what we have been led to believe, as we erronously assume 1 kerbal-perceved "second" is equal to a human, x million vibrations of a cesium atom second, and so assume that 9.8 kerbal meters per k-seconds per k-second is the same as our familiar earth gravity.
But is a k-second is actually, say, an earth minute, the gravity of Kerbin would be 9.8m per minute per minute, or about 1/360th of an earth gravity.
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19 minutes ago, K^2 said:
And if the robots break? More robots? We can't build robots that don't require human maintenance down here on Earth. What makes you think we can do it on Mars? I mean, sure, if it's a multi-generational project, maybe we'll come up with something substantially better. But again, we can build sustainable - not self-sustaining, but truly sustainable long term - colony on Venus with tech we have right now. We do need a larger lifting rocket, but if SpaceX gets Starship to fly, that basically solves that problem. So we're back to the simple fact that sustainable colony on Venus by the end of next decade is something we can pull off if we re-task existing budgets, and it would be something we can grow incrementally. Sustainable long-term colony on Mars might not be possible this century, and we have to build most of the infrastructure before we send in people.
We don't make humans that don't require maintenance, either. Zero maintenance is a trap that needs to be avoided. Instead, you design for automated maintenance- parts being replaced of off the shelf plug in parts, which can be installed by another (or even the same) robot.
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18 minutes ago, GoSlash27 said:
Ya know... This is not a thread to point out flaws simply to bash on SpaceX, but rather offer concerns and potentially helpful criticism. You are totally correct in pointing that out.
I wonder if you realize that the only thing less useful to SpaceX's effort than that is posting things like 'they already have it figured in, guaranteed'. Maybe they *don't* already have it figured in, and maybe it's in *their* best interest to check and make sure.
Tell ya what: How about we just limit the conversation to potential pitfalls, concerns, and potential solutions and agree to not try to convince people who don't work at SpaceX about our opinions?
Fair?
-Slashy
This is how your complaint comes off.
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3 minutes ago, mikegarrison said:
I am well-reconciled that I will never be going to Mars, but I would want something that would dwarf Starship. Of course, we're talking a whole different level of investment. Like a global international priority.
How expensive would it be to build in orbit at 200 dollars per ton?
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Just now, mikegarrison said:
I wouldn't want to fly Air Force One to Mars.
How about two air force ones flown near each other, with weekly inter-ship videogame tournaments?
The important part is that starship has the volume for a wide variety of services and a dozen people at the same time. And heavy equipment that doesnt get used until you're on mars, gets sent on a cargo flight in the same convoy.
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1 hour ago, mikegarrison said:
Starship is known to be the TARDIS. It can fit an infinite amount of stuff and also 100 people into a volume that is smaller than what 6-ish people live in at the ISS.
Not all at once, but it does have the habitable volume of Air Force One.
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11 minutes ago, king of nowhere said:
Some people here are way more expert than I am, but I am sure that at spaceX they are not total morons. They built spaceship to land on Mars, using the belly flop manuever, they will surely have made all the calculations ahead of time to figure out flap size and descent times and everything.
there's still a lot of things that can go wrong with the fine details, and since this is rocket science it just takes a tiny detail to destroy the rocket. But I just refuse to believe that a multibillion space industry that made dozens of successful launches would just make a blunder as stupid as not calculating the flap size with precision. One may as well suggest that they forgot to put in a command pod.
the problem with the lack of ground is that a colony, to qualify as such, needs to be self-sustaining. which means it must get resources from the environment, because as much aas we can try to send a closed-cycle ecosystem, there will be losses.
What can you get from Venus atmosphere? Some CO2. Some sulfur. Maybe there's enough sulfuric acid in the air for efficient extraction, in which case you can also get hydrogen. But what about everything else? No nitrogen, no phosphorous, sodium, chlorine; all stuff you'd need to grow plants. No iron, silicon, or anything else you can use to make buildings. Those things don't float in the air, so you need to go down on the ground to get them. So you need to make machinery that can survive the 400+ degrees and 90 atmospheres.
Granted, if we had those machinery, and we could conceivably reach the surface of venus in a sort of submarine, and extract from there the resources we need, I'd be all for it. But until we have that, Venus is not feasible. Even when we will have that kind of technology, the amount of material we'd need to send to venus to sustain a colony that could extract resources on its own is staggering. On mars, you can get water, iron, silicon, just by digging.
The best way to "mine" venus might actually be by asteroid impactor. you're already set up to process ambient particulates, so drop a dinosaur killer and mine the dirt out of the air.
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5 minutes ago, GoSlash27 said:
Yes they do.... And if they are relying on the engines to soak up the DV instead of the atmosphere, they certainly have that option. It just means a lower payload capacity than they're currently expecting.
The other option would be to put much larger fins on it. Either way, it's a potential problem with the current design that they're either unaware of or have decided isn't a problem. Pointing these potential problems out is what this thread is supposed to be about... or at least so I thought.
Best,
-Slashy
These things are trivial to calculate. They already have it figured in, guarenteed.
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19 minutes ago, GoSlash27 said:
The SpaceX plan expects that terminal free-fall portion to take 3 minutes on Mars, and it was demonstrated to be less than 2 minutes on Earth. That's a problem that SpaceX needs to look into.
Best,
-Slashy
What problem? The engines work just fine for 3 minutes, there's no problem for them to look into.
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1 hour ago, GoSlash27 said:
Rakaydos,
The most problematic parts of the "minimize imports ASAP" approach are the increased stakes (a whole lot of humans), the massively increased dependence on a single platform not having a catastrophic failure, and increased pressure of "sunk cost" that comes with going with the full intent to stay rather then visiting to learn *how* to stay. Dude's not going to build an entire city, run into an insurmountable problem, and then just shrug and say "oh, well in that case nevermind".
JMO,
-Slashy
What do you mean by "massively increased dependence on a single platform not having a catastrophic failure"?
Each Starship and each superheavy will have it's own flight history, meaning most flaws can be identified as being vessel specific. The chances for a class-wide failure requiring remedy to affect a synod launch, without getting a waiver for at least resupply, (sunk cost FTW!) is slim, but is also the reason the mars base keeps supplies on hand for a missed synod. The chances of two sequential synods both being obstructed by critical, class wide failures... AFTER successfully getting a significan population to mars, is ridiculusly small. But Falcon Heavy can still throw the most essential supplies to mars if that happens.
"going with the full intent to stay rather then visiting to learn *how* to stay"
I dont understand the difference. Nothing is going to be perfect on the first go. every problem that arises is a learning experience, one more thing that needs to be mastered for an independant mars city state. Going to stay IS learning how to stay.
You also seem to be positing that there will be some diffictlty that is completely insurmountable, no matter how much mass they can sling to mars. I do not buy your arguments here. Even something as fundamental as gravity can be compensated for with spinning carousels. And building said carousels out of martian iron, makes it that much easier. (carousels are not in the current plan, because they probably wont be needed. But they are an option if they are.)
But hey, if you have a functional fuel plant, which the first crew will set up, you can always bring everyone home packed in like sardines. If you cant get a fuel plant, it's the same problem whether the intent is a city or a research outpost.
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26 minutes ago, GoSlash27 said:
Well, you can see it in the free-fall from 10 km up, which is equivalent to Martian atmospheric density at the surface. IIRC, the Angry Astronaut had a video on the subject a few months ago. I'll see if I can dig it up for you.
Best,
-Slashy
mars pressure is more like 35+ KM up, IIRC. But they did do mars pressure retroburns in the early days of F9 reuse, and that data is still valid. SN20, if it survives entry, will also test upper atmo descent. They already know they can do landing thanks to SN15.
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@GoSlash27 why would a slow expansion be less problematic than a "minimize imports ASAP" approach, if the risk is sunk cost and supplying these people forever?
A research outpost would be just as vulnerable to spaceX going under, and would require more imports per person than even a partially sustainable mars city.
One advantage to the mars rush approach is the same advantage SpaceX has when it's willing to test to destruction when oldspace believes failure is not an option. When something goes wrong, you know exactly what actually went wrong. They key aspect is to allow for failures of this sort without risking lives by having backup supplies ready to go, as they did in Biosphere 2 (though the biosphere 2 management hid it, and the various resupply mission from the press- another flaw of "failure is not an option" thinking) This kind of high-pressure feedback on research and development is exactly what's needed to make advances quickly.
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The biggest problem with a venus colony is coming home. Earth equivilant gravity and pressure means you're going to need a superheavy to get starship back to orbit, and the logistics of superheavy launch and landing from an airborn, floating platform boggles the mind. Not to mention SSTOing a superheavy into space to get it to venus in the first place.
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37 minutes ago, GoSlash27 said:
Rakaydos,
I think his point is that there is no machine that can make a cat. I agree that cats aren't essential for human survival, but there are lots of things in our biosphere that are essential and just as impossible to produce with machines.
You asked me what the most difficult thing to produce with machines would be, and I really don't know which would be the most impossible. Just glossing over the food chain (one of myriad essential chains), should I start with all the basic elements that we need that aren't there and can't be replicated? Or the more complex organic elements/ compounds composed of them? The nitrates and organic matter that fertilize the soil, the colonies of diverse bacteria that fix the nitrates and break down the biomass to provide nutrients? The plants that feed the animals that feed us... The necessary vitamins, minerals...
Or should I start at the top and say that there's no machine that can make fried chicken, buttered corn on the cob, and mashed potatoes/ gravy out of the Martian materials?
Somewhere in the middle, like there's no cow replication machine?
I mean... we can't make a machine that makes any of it, it's all complex, and all necessary... and that's just food with none of the fine details even considered.
Earth's biodiversity cannot be replaced with a machine, and we absolutely need that. An entire ecosystem must be transported to Mars, and must be of a scale that dwarfs the human contingent, and we're still learning about the essential niche roles that life fulfills here on Earth; we can't even set an upper bound on what's essential.
Best,
-Slashy
I said replace, not create. Feel free to give the list of basic elements you believe are not present on mars- dont bother with transuranics, since they want to focus on solar power.
We do have a machine that makes nitrates- most fertilizer is artificial, and a significant portion of it uses methane as a feedstock, which the rocket fuel plant will have plenty of.
Soil bacteria may be impossible to easilly replace- it's literally natural organic nanotech- but is self replicating, meaning that you only have to import some and keep tabs on it's growth through native growth media.
Plants, animals.... look up Aquaponics, it's an interesting field. Vitamins and minerals, a part of this healthy breakfast....
Fried chicken is not a requirement for self sufficency. Meat substitutes are a developing field, rendering livestock obsolete.
The trick is to break down the big problem into manageable sub problems. Gruel and water will keep the body together, even if earth imports make life worth living.
270 by letting it unlock 3x
The Analysis of Sea Levels.
in Science & Spaceflight
Posted
Tides already account for more than +/- 1m from average sea level. Those islands already have to deal with tides, but it's probably gotten worse as (checks source) 425 billion metric tons per year melts and joins the oceans.