KASASpace
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Posts posted by KASASpace
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If you want to get to a reasonable fraction of the speed of light, like 70%, then you need a mass fraction that is just GINORMOUS, even with antimatter.
So, probably not getting to .7c anytime soon, but if fusion is on its way like people say, we might get .1 or .2c. Orion could get to Alpha Centuari in ~130 years, if we build the interstellar version that's fast. Basically, it's possible, but the biggest obstacle is not mass fractions or speed, but POLITICS. Who's going to fund a .1c probe?
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OTRAG was liquid fuel. Model rockets are pretty much always solid fuel. You can't just stick a bigger tank on.
I said OTRAG's staging, not OTRAG itself.
If a model rocket is a low power motor and a small-ish size, you can!
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A very interesting thread. I will only reply to some of the later posts because it would be too long otherwise.
If I want hydrogen I would go for a gas giant. There I would get an almost infinite supply of very high concentrations of hydrogen in the upper atmoshere that I could also use for areocaputre. I think the real charm for a spacefaring race would be our oxygen and any complex organic compound a.k.a ressources you only get from an active biosphere. Everything else they will probbably find easier elsewhere.
Actually gas-giants may not have hydrogen, but a lot of them do. However, that close to Jupiter the radiation is probably too extreme for almost any civilization's technology to survive.
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They have a flight time of a few centuries. A little prograde/retrograde will put Jupiter wherever in it's orbit they want. A little more, and they can plan multiple planet alignments.
It's not like they wont know about gas giants in their destination system before they leave- we know as much already for plenty of exoplanet systems, and we cant even see them yet, just extrapolated their existance.
We actually know very little about the outer planets of those systems, because they might be taking too long to pass in front of the star for direct observation, or the "wobble" is so small due to distance that it's not observable.
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Kerosene might be a better choice than LPG for fuel; easier handling (liquid at STP), lots of developed rocket engines for it, similar Isp.
How were you visualizing it taking off and getting to ramjet altitude/speed?
I chose propane because it's more efficient, almost 30 to 50 increased Isp over kerosene, and it's a lot easier to acquire propane.
I don't know, perhaps some sort of magnetic acceleration? A hydraulic system akin to the systems onboard carriers?
Where they're basically talking about using a rocket or other first stage to get up to speed for the ramjets. That wouldn't be SSTO.
I never said it was final. There are other methods.
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Too much weight. You have 3 engines on that thing (4 if you include the system that brings your RAM online) wreaking havoc on your fuel fraction. I don't think you appreciate just how much dV it takes to get into earth orbit.
Too much weight? Do you understand how a ramjet works? It's practically a tube with an injector, although that's a gross exaggeration. A ramjet's biggest difference from a scramjet is geometry, so not much increase of weight there. The heaviest engine will most likely be the rocket engine itself, although it could be pressure-fed, but that's not that efficient.
"taking off" at altitude violates the concept of SSTO
I never said that, I said:
"takes off" and flies to an altitude
A turbo-compressor is complicated, and that's why I didn't mention having one onboard.
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We need to start small. Maybe a 2U in LEO to start with and figure things out. People would be more likely to back future projects if we have some experience. The U.S. is probably the best place to construct as that's where the most users are and probably has the cheapest shipping because that's where the parts are already.
Actually, 10x10x5 cm kits are available, and if we do a PR mission first I would say that is the size to go with.
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Perhaps, if we only get LEO, we could launch a 1U that can separate. It then flies away a bit, rendezvous with the detatched piece and dock. We could use this to test out in-space refueling, with multiple consumables transferred (electric charge, fuel for propulsion, etc.)
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Problem with having a bunch of engines is that they are dead weight when you can't use them.
Yes they are, but you will gain large amounts of cross-range capability with engines. Plus, ramjets are extremely simple, with virtually no moving parts.
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What about landing on Europa? Perhaps with airbags? It hasn't really been done has it? Maybe Enceladus? I say this because it's bold and very KSP. Problem with this is mainly radiation, but I don't know about Delta-v requirements to Europa.
I would go with a 2U because it seems like a better plan than a 1U, 2Us have up to four times the volume, unless it's just two 1Us attached at one side.
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A custom built model rocket could all right. Most model rockets with store-bought engines have fuel only in the engine, giving really small Delta-v. Now, using extended fuel tanks you could do it with a simple guidance system and "infinite" staging, which means staging immediately around a core (OTRAG did that).
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Let's say an asteroid similar to the one that killed the dinosaurs strikes again. A few thousand people manage to live for a thousand years in an underground bunker system under conditions similar to the Real World of the Matrix trilogy. After emerging from the bunker, they find a devastated environment on the surface, composed of small shrub-like forests, undergrowth consisting of mostly ferns, the main components of land fauna are rodents and birds. Signs of civilization, eg. cities, structures, machines are nowhere to be seen.
The bunker is similar to a self-sustaining underground Martian base, or a generational ship, but after all these years, the systems are starting to fail, and there are no heavy industrial factories or raw materials stored down there, just some simple machines that manufacture products needed for day-to-day living from recycled materials.
We wouldn't survive that impact. But maybe smaller. There's still the possibility of maintaining an underground forest and get charcoal from it.
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You forget, that it is not the metals that matter, but something much much different. Even if we were blasted into the Neolithic age, I know about a piece of technology that could take us to the Bronze Age, it's called the Bellows. It's a compressible container that "blows" air into a fire, making it hotter. This allows for that fire to melt metals. Then we can use those metals to make tools.
Plus, that would only happen if everyone with knowledge about industrial technology died in that disaster.
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Hmm... you generally talk about gravity slingshots as something to get you out into interstellar space, but what if the alien probe timed it's arrival to slingshot jupiter to "capture" into Sol system, like you might use Laythe to capture into Jool orbit?
Since an interstellar slowboat probe has nothing but time, it then procedes to get on the Interplanetary Transport network and slingshots everywhere, beaming close up images and radio data back to the home system.
That's a good point. Although it would depend on a lot of factors, like where Jupiter is in the solar system (if you can get an encounter where the gravity of Jupiter can pull you towards the sun's retro grade vector, then it's possible.)
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So, I have been thinking about this topic for a while, and I came up with this:
Some sort of method of getting the craft to high enough velocities so where a ramjet provides decent thrust, perhaps a JATO like device, I don't know.
Then, the vehicle "takes off" and flies to an altitude, and a velocity, where it starts to lose thrust. Now, the ramjet is actually a bypass around the actual main engine, which is a scramjet. Since ramjets are fairly effective up to ~Mach 5 to 6, the ramjet will throttle down and the scramjet will throttle up so that the thrust remains the same. Eventually the ramjet fully shuts down and the scramjet is the only unit burning. Using the scramjet to get to fairly high velocities and altitudes, you could potentially cut a large amount of delta-v required, thanks to lift. After reaching a decent velocity and altitude, a rocket engine fires. At this point the scramjet throttles down and then cuts off thrust. The rocket engine (perhaps using liquid propane, which is in the upper 300s for Isp) will finish the trip to orbit.
So, any thoughts/improvements?
The technology for a "bypass" "ramjet" has existed since the 1960s in the SR-71, which is what this ram/scram-jet is based on.
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or perhaps we already have...
Then we would have something pretty good.
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Fission fragment propulsion has the possibility of millions of specific impulse. We could use that. Antimatter, *shivers* is tough to deal with, so probably no. How efficient is nuclear energy again? Much more than chemical, but still low. If we could get some sort of interim between antimatter, with its efficiency, and nuclear energy, with its relative ease of use, we could probably do it.
Either that or get lucky with wormholes.
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Well, the most likely scenario is that a large probe will enter the solar system, perhaps fairly close to the sun, perhaps far. What will most likely be the case is an unmanned vehicle that will enter the solar system and then move towards the planets of the system and deploy smaller probes for long-term operations. Maybe a few probes for the Gas-planets to explore the moons, an Earth probe, Venus probe, Mars, etc.
Now, the design will probably be similar to the Daedalus concept, an interstellar staged spacecraft. Although that was designed for flybys, but with a solar sail coming close to the solar system you could possibly brake........
They will most likely come to gather science, like our probes but interstellar. Perhaps we could rendezvous with one of the probes and reverse engineer the propulsion system.
Earth is valuable for a few reasons, large amounts of Carbon, large amounts of Hydrogen in one place, so if you have fusion engines......
We're here, we have creative mind that can think up almost anything. We have an amazing adaptability trait that some other species may not possess in the universe.
Asteroids are useful for metals, however, metals may not be useful for an interstellar civilization, especially since metals can have reactions with radiation that spawns more radiation.
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You put some kind of thruster on the portion of the structure at GEO, that lets you do corrections and avoid obstacles, some have even suggested having the surface end of the tether connected to a ship at sea to give some maneuverability.
Foolish to use rockets for the ascent, electric power is the way to go. Payload per car doesn't matter that much as you can have a train of cars moving up and down the tether simultaneously. The transit times will be long, though, likely days to GEO. The point is to avoid delta v and the tyranny of the rocket equation.
Maybe carbon nanotubes can do it, maybe some other material we haven't discovered yet. Space elevators are much more feasible on the Moon or Mars, but it's hard to imagine enough demand to justify them anytime soon.
Actually, electric power lifting that many tons? Not yet mind you. It would take enormous amounts of energy you just can't get with reactors on ships. Plus, you would need to find the ship.
What if the portion at GEO is not moving the appropriate speed? GEO is a type of orbit, not an altitude. If there were any counterweight it would most likely pass the speed on to the counterweight. Which means no portion actually AT GEO.
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A logical application is what happened in Contact by Carl Sagan, they were there, but only their minds, not their physical bodies. So, find enough alien stuff to build a special part that takes you, and your spaceship, to another star system, in the Kerbal's minds.......
That or more timewarp, or possibly alien warp-gate? A lonely question mark in the inky blackness of space, at least in the tracking station. Maybe the tracking station could have an Artifacts tab so you can look at easter eggs you already found.
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What if it's a probe? A self-replicating probe (capable of building more of itself with in-situ utilization. So, a monolith. With knowledge? We can only hope it brings about good things.
Or some kind of "Rama" flying around.......
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Actually, according to our current knowledge, they're made out of nothing. It's the best we can do now.
Nothing doesn't exist. What does exist is the lack of something, which is still a thing. So, therefore they are made of something, the lack of it.
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No no, this isn't a problem. You don't just send them there. It's kind of like climbing tall mountains. You acclimatize. So, perhaps using an orbital centrifuge you could slowly get the humans to get used to the new gravity levels. And then do this on the way to Earth if they ever visit. You would be surprised how well the human body can adapt to new environments. And the air problem for the moon is more than gravity, but the amount required with that low gravity to get the proper pressure at sea level. Good luck with that.
If only Jupiter hadn't stolen some of Mars' mass before Mars even came to be.........
The Moon isn't a likely target for terraforming, but Mars is. Venus is, just, no.
Now, here's something.
Increase the mass. Perhaps breaking up asteroids and raining them slowly over Mars could eventually increase it's mass to have the Gravity required to hold in an atmosphere at, let's say at least half the pressure at sea level on Earth. The percentages of Oxygen to Nitrogen can vary. You now have other problems. So, stop with the Gravity thing and accept that we aren't masters of the universe. Leave some things alone.
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Is it though? It was worth billions new, but I imagine the depreciation on a space station is pretty eye-watering. Especially when there's a very limited number of people who would buy one off you.
Things aren't worth what the original buyer paid for them, they're worth what somebody would give you for them today.
Actually, the idea is that one bird in the hand is worth two in the bush. One resource in space is worth many more that aren't in space, simply because it's there. If there were no gas stations along major interstates, than you are kind of screwed. In space that can be fixed by just launching everything you need. But remember, the station was supposed to be a staging point for lunar trips, so, a gas-station and other supplies.
Basically, logistics. In. SPACE!
So, just because it is literally THERE, it has at least millions of dollars of potential, not necessarily value, but potential.
Could a Gas-planet the size of Jool exist?
in Science & Spaceflight
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Everything in KSP is scaled down, but when I looked at Jool's radius, I noticed it was around 6,000 kilometers. That's ten times Kerbin, which if I recall is supposed to be one-tenth the size of Earth. So, Jool is small.
Now, on to my question, could a gas-planet the size of Jool even form in a young solar system?