Ember12
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Posts posted by Ember12
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Agreed, getting it from gas giants is a far better idea IMO.
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I agree that all this would be cool. I don't know if they'll add cities, but given the amazing terrain work we've seen of other celestial bodies, I would be shocked if Kerbin didn't get that level of detail.
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2 minutes ago, Strawberry said:
heating of the corona is "minimal".
I would dispute this, because conductive heating is not the only way that your ship can be heated. As I said before, the sun puts out around 64,000,000 watts per square meter. This does not depend on atmosphere. That energy is going to affect you even in a vacuum, because it will all be light and radiation.
6 minutes ago, Strawberry said:diamond has an observed compressive strength of 60 GPa (keep in mind the observed, diamond can probably go higher), meaning that it can withstand ~13,500,000,000 pounds of force per square meter with its current highest observed strength.
Would you mind walking me through the math you used to get that? Did you calculate a solid block or a hollow fuel tank?
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54 minutes ago, Strawberry said:
That's why you go fast enough to get out of there in less then 40 seconds.
Let's assume you take a perfectly straight line, and just graze the solar surface. Let's also assume that you encounter that amount of heating when within 135,000 miles from the solar surface (not nearly far enough to be outside the corona). By my calculation, you would need to travel 1003543 miles inside that radius, and to do that in 40 seconds, you would need to move at over 90 million miles an hour, or 13 percent of the speed of light. At the sun's surface, the 10-meter-diameter spherical fuel tank I mentioned earlier would experience over a billion pounds of drag force.
And this is an optimistic assessment. You would also be heated up during solar approach, and even at this speed, you're dragging along a mass of hydrogen comparable to the mass of your starship, and this isn't even taking into account the cooling of the hydrogen you're taking in.
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4 hours ago, Strawberry said:
That assumes an emissivity of 1, meaning it absorbs all light. Flat graphene has an emissivity of 0.025, getting us only 5,600,000,000 joules transferred. The maximum amount of joules a gram of hydrogen can take can be calculated as the specific heat (14) times the temperature gradient (4000-20 so 3980). Dividing the joules per second by this number gets us only 1407.035 kilograms a second required, a far more manageable amount.
I did indeed not consider emissivity, but the process is still not feasible. Assuming you multiplied my number by 0.025, that means that you would burn through 3 skyscrapers of hydrogen every 40 seconds. An amount of hydrogen comparable to the mass of your ship every 40 seconds.
And you can't escape by going higher or lower. That 64,000,000 watts per square meter is still going to affect you anywhere nearby, regardless of the gas density (the denser, cooler gas inside the Sun will impart the same thermal energy as the stuff nearer the surface).
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I did the math on cooling a starship at the solar surface, and it would not be feasible if I didn't make a mistake.
In this discussion, someone estimated that a starship's radiation shield was 100m in diameter. The shield was about 1/4 as wide as the conical starship was long (not counting the engine bell) so you'd need a conical fairing 50m in radius and 400m long. The area of such a cone would be about 70,000 square meters.
Only half of it is facing the sun, so we can divide that by 2 to get 35,000. Let's imagine we cover it in reflective paint so that only 10% of that gets through, bringing it down to 3,500 effective square meters.
The output of the sun is 64,000,000 watts per square meter at the surface, which is where you are. This, multiplied by the 3,500 effective square meters, gives a total of 224,000,000,000 watts.
One watt is one joule per second, so you need to remove 224,000,000,000 joules per second. Hydrogen, the proposed coolant, has a heat capacity of about 14 joules per gram Kelvin (j/gK). This can be rearranged into 14j=gK. Assuming the hydrogen starts at 20 Kelvin, and you're okay with your (graphene) starship reaching 4000 Kelvin, K (the change in temperature) is about 4000. So 14*224,000,000,000=g*4000. Divide by 4000 and you get 14*224,000,000,000/4000=g, or 784,000 kilograms of coolant hydrogen a second. This is about three times the weight of an average skyscraper.
There's just no way to carry that much coolant on a ship of that size. This would not work at all.
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1 hour ago, Strawberry said:
so its far more practical to just collect the regolith from the surface instead.
Earlier in the discussion, I got the impression that you were saying "This wouldn't be useful but it would be fun" about the harvesting of gases from stars. If this is the case, harvesting airborne regolith would fall into the same category.
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29 minutes ago, Pthigrivi said:
if you’re designing a system for procedural infrastructure over long distances wouldn’t pipelines be easier and better in most situations?
Unless you want to move solid material.
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You're right, I totally misread that statistic.
On the heat front, do you have any idea how to calculate the amount that would be needed to cool an entire ship?
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Okay, thanks, I get it now. I agree with your math on the fuel-obtained front.
But the fuel tank is not the whole ship. The whole thing has to be cooled, which for a big starship is going to be very hard. There will also be a LOT of drag on various parts of the ship.
I used this drag calculator, with the following values: A velocity of 430,000 mph (the speed of the Parker Solar Probe), an atmospheric density of 1.41 g/cm^3 (the density at the surface of the Sun), a drag coefficient of 0.1 (I'm calculating the drag on a spherical fuel tank, and I believe spheres have about that drag coefficient) an area of 100 square meters (a tank with a 10-meter diameter).
The output was over 50 trillion pounds, which is far more than any strut system could hold. It would also implode the tank.
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I don't quite understand the part where you said
16 minutes ago, Strawberry said:q1 = m1*14*3980= q2 = m2*12*1778
Could you explain how you got that please?
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No, I did not get that from a paper, so it could be wrong. But you're gathering hydrogen, it's at the temperature of whatever layer of the sun you're in, and now it's inside your ship. Assuming that its temperature is too hot for your ship to function, you'd have to expunge at least an equal amount of hydrogen to keep the temperature down, making fuel gathering useless. And your spaceship has already been heated up by radiation as it approaches the star.
As I said, this does not have scientific backing, so if you find anything that disproves this I will stand corrected. But I can't see any way that you could gather more gas than you use for cooling.
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1 hour ago, Strawberry said:
If you have graphene with a good thermal insulator underneath, you can easily get the heat to where you want it to go due to graphene transferring the heat where you want it to. Your best bet would be a special graphene coated chamber to where the gas enters, gets heated up here instead of the large tank,
The problem is, it would take a lot of gas. Your spaceship would be heated up as it approached the star, so the gas would be pretty hot to begin with, and it would be depleted quickly. If you're using hydrogen you've gathered from the star, it's already really hot so it won't give any benefit.
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There's not really a "tightrope". If there's enough gas to collect, there's enough to melt your spaceship, and there is not a good way to get rid of this much. As you suggested, you would have to concentrate the heat in some hydrogen and then spit it out. But this would require a ludicrously powerful heat pump, with a mass comparable to the rest of your ship, and even that might not be enough to keep the rocket's skin from melting off.
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6 minutes ago, t_v said:
Flying at 30,000m/s, if you just used a standard 1.25m intake, you would be taking in 36,000 cubic meters of the not very dense gas every second
The sun's corona is 10^13 (ten trillion) times less dense than Earth's atmosphere at sea level. To put that in perspective, a one-square-meter intake could get as much gas from traveling one meter on Earth as it would get from traveling the distance to Neptune and back through the sun's corona. That means circling the sun more than two thousand times.
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Right, but if you're flying through an extremely thin part of the sun's atmosphere, you can't get that much material from it.
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I don't understand the "why wouldn't it". You can't use any gas as a fuel. There are three main types of engine to consider:
Combustion, where you burn something like hydrogen with oxygen, or use more exotic fuel mixtures. Possible fuels: Oxygen, hydrogen, hydrocarbons, or more complex molecules.
Nuclear propulsion, where you heat up a light gas and fire it out the back. Possible fuels: Mostly just hydrogen and water
Fusion engines, where you fuse atoms to create energy and thrust. Possible fuels: isotopes of hydrogen and helium.
If a planet has one of these in its atmosphere, you're in luck, if you can collect enough to offset drag. But many planets in our own solar system don't have any of these. Mercury, Venus, Mars, nearly all the moons of Jupiter and Saturn don't have any of these in their air. Actually refueling a combustion/nuclear rocket would not be something you could rely on.
Refueling from a star? Just... no. You can't do it. The sun's corona clocks in at two million degrees Kelvin. There is literally no material known that can stand up to even a fraction of that.
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I don't think this is really feasible. If a planet had an atmosphere you could make fuel out of, it would probably have combusted already. You could synthesize H2 and O2 from water vapor, but atmospheres aren't that substantial. If you could somehow condense all of the water in a 1 meter square of Earth's atmosphere, going up to space, it would fill two 24-packs of water bottles. Of course some planets might have a much higher concentration, but it would still be hard to get enough, even just to counter the speed lost from aero drag.
For stars, as soon as you get anywhere near the atmosphere you'll get vaporized. KSP2, while having futuristic technologies, is mostly confined to stuff where we know how it might work. Nobody knows how to survive that close to a star.
There is, though, one place I can see this being useful. A very good fusion fuel is Helium-3, which is found in the atmospheres of many gas giants. So special spaceplanes that harvest it from Jool-like planets and ferry it to an orbiting starship would be a useful application of this idea. But flying starships directly through an atmosphere is never really going to work, because you have to add a huge amount of (very heavy) heat shielding and structural support, which would severely compromise their range.
Edit: I hadn't considered the possible collection of hydrogen for a nuclear engine. Given nuclear engine exhaust velocities of around 10 km/s, this could feasibly be used to produce enough thrust to counter the speed lost to drag with some left over.
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On 7/12/2022 at 7:18 AM, SkyFall2489 said:
And designing battleships in KSP1 using LunaMultiPlayer. And reading through the old Naval Battle Club threads.
Combat in KSP2: Why go to all the trouble of blowing up your own spaceships when you can get someone else to do it for you?
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10 hours ago, BowlerHatGuy2 said:
I think it would be cool if you could have different engines that pull your cars at different speeds. You could have a workhorse engine that’s relatively slow but cheap and reliable, and another high speed one that’s more expensive and difficult to design, but is much more effective in the long run.
Assuming that trains are being used as supply missions, the speed of the trains doesn't matter so much. If you send a train every 2 hours, they will arrive every 2 hours, whether they go 10 miles an hour or 100.
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29 minutes ago, Nazalassa said:
create and edit Monorail Paths (or Railways if you prefer)
I can't imagine there being monorails, because conventional railways have a much higher load capacity. Monorails are used mostly in urban areas where space is a big concern, but space is not a concern for routes across uncharted wilderness.
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50 minutes ago, BowlerHatGuy2 said:
You could just have drag-n-drop system and “draw” the rails like Jurassic World Evolution or Astroneer.
Having the rails line up with the incredibly detailed ground we've seen might be a bit tricky. Plus, do you really want to drag your finger over 57 kilometers of terrain to link up two bases? I think that's the main issue, the scale of the planets you're building on.
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While there are no official numbers on how many KSP players are on Mac/Linux, it's probably pretty high. By my count, in this thread so far about 13 people have stated that they want Mac or Linux support, compared to about 12 who were against the idea or neutral. Obviously this is not a very accurate way to determine platform preferences, but it does indicate that KSP2 would sell a lot more copies with Mac/Linux support.
This may be in part because Mac and Linux devices are often preferred among scientists and researchers, who probably make up a disproportionate number of KSP players.
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I think I'm missing something here. Are you talking about only the effects of being extremely close to a star? If so, I don't see what interstellar probes have to do with it. Both Voyagers are fine, and they're protected only by aluminum foil.
realistic country shapes
in Prelaunch KSP2 Suggestions & Development Discussion
Posted
I think they meant having Kerbin's continents have the same shape as Earth's. If that is what they meant, I don't like the idea. I feel that the Kerbal universe and ours are separate and distinct, and it should stay that way. Having Kerbin look like Earth, but be in the Kerbol system, that would be strange.