p1t1o

Today? In terms of launch-for-launch? No not really, especially since they are so difficult to build/exist on the edge of technological feasibility. But fast forward to an arbitrarily far future. Is this a future where you see commuting to a job in space as a norm? Or at least people vacationing there for the same price as a skiing trip? If you do, then this world will need vastly increased capacity for launching vehicles. An SSTO might not be better than multistage today, but what if you want to launch 10,000 flights per day, globally? Then I think the savings and turnaround time, might add up. Maybe.

Tip of the Hat to "The Moon is a Harsh Mistress" as well. TANSTAAFL

Theres another contact email and a telehpone number on the "sponsors" page. https://copenhagensuborbitals.com/sponsor-page/ You're not interested in sponsoring or donating (although you will be donating your time I guess? And potentially some limited form of publicity? If you had to argue it that way.) per-se, but it might get your foot in the door. It lists the name of everyone who has even just donated a little cash, so they seem to be open to talking to individuals.

Pegasus is not operated by the military. Turns out for small satellites (<500kg) it can be a fair bit cheaper, especially for launches into odd orbits. Its not that 900kmh is particularly fast, but launching above most of the atmosphere gets you some significant benefit.

What a great reason to send a child to space. I guess in the Sudan they have to fight in wars and stuff too so I dunno what Im worried about really.

@Pawelk198604 Did...did you just compare the risks of going to space to skateboarding? Sentimental claptrap. You know who cannot afford to be sentimental, and have to be by the exact-letter-of-the-book-at-all-times or many people die horribly? Astronauts.

I did leave a visible clue in the post guys! I was more concerned about it seeming disrespectful (which of course was not my intention.)

People here generally happy to answer questions, or they dont bother commenting, you won't hear "RTFM nuube!!" very much here Pretty much all the questions have been asked at some point, by someone, so dont feel bad. If you ask me, wikipedia is a good start for most things, and most pages will have plenty of links to further info. https://en.wikipedia.org/wiki/Gravity_turn There are two links you need though, if you are playing KSP. They are a bit more advanced, but if you get into KSP for more than a couple of weeks you will want the info contained within. (and they are by far THE most referenced links on this entire forum - ok I cant prove that, but you get it...) http://www.projectrho.com/public_html/rocket/ - This website, intended for people writing science fiction stories, contains a huge amount of material describing real-life and near-future technology in terms of space travel. Also has extensive sections on hypothetical combat in space. The propulsion tech section is also highly relevant. https://library.sciencemadness.org/library/books/ignition.pdf - This is a book. Its a legit link, dont worry about downloading it. It is a history of research into rocket fuels, written by a scientist who worked on the forefront of it. It is actually quite a fun read and is written in a very easy to digest manner (its not full of maths or theory you need a degree to understand). It brings a lot of rocketry into real perspective. Welcome to KSP!

A gravity turn is an efficient ascent - a gentle curve all the way up with almost constant acceleration, not a vertical section followed by a turn and a more horizontal section. A gravity turn begins almost as soon as you clear the tower, but you will have cleared the "lower atmosphere" before gaining too much of an angle. Its drag though, that you are avoiding, heat should not be a concern since the lowest part of your trajectory is also the slowest. In KSP the heat/flame visuals display at quite low velocities though, but IIRC do not necessarily represent a damaging heat flux. Having said that, with a proper gravity-turn ascent and acceleration profile, you shouldnt even get the heat/flame visuals as the acceleration should be fairly gentle (~2-3-4 Gees). There is no point in blasting away at many Gees, then you WILL lose a lot of dV to drag.

Did they? How'd that work out? RIP Challenger + crew

You know, experimenting on children is generally frowned upon. Whilst the first crewed missions had a generous helping of propaganda value, its a YUUUUUUUGE stretch to make a comparison between that and this. *** Instead of sending a single child to space, how about we send ten thousand to space camp for the same price? In terms of "inspiring a generation" it would be vastly more effective / ethical / safe. *** Apologies to all of those kids reading that would love the chance, I want you to go to space, just

Im going to go out on a limb and say this is a pretty stupid idea. Pure marketing. Its not that there wouldnt be any benefits, like I got a benefit when my dad took me to see the captain on a flight to canada when I was 4, but the factors against are significant and numerous. And for what? Give a single child a unique experience? Generate publicity? Sentimental tosh.

I supposed you could call the B-52 mothership of the Pegasus launch vehicle a "jet powered stage". Amongst various other similar arangements.

Ok so Bonny Tyler will be performing "Total Eclipse of the Heart" during the event onboard one of those eclipse cruise ships. Sometimes all is well in the world.

Like it. Why is it called "Mandela"?

Sometimes when I turn my computer on, the desktop will start to my main monitor, with my secondary monitor active. Sometimes when I turn my computer on, my main monitor will remain inactive and the desktop will start to my secondary monitor at 800x600 resolution. There does not seem to be a pattern, or anything I can do to affect which outcome will occur. I just have to turn it off and on until I get the right one. Computers. Does anybody really know how they work?

Not exactly. IR works well in space, especially at long ranges, but approaching a planet you'd be vulnerable to detection by radar, it'll take more than a coat of radar absorbent material to disguise a large ship.

Batteries are not a power source, they are power storage/buffer. To illustrate: an Li-Ion battery stores maybe 460kJ per kilogram of battery. Potato chips contains approx 20-30MJ per kilogram. Gasoline, ~45 MJ/kg Plutonium (from decay) ~ 2.2TJ/kg (2,200,000 MJ/kg) Something like a solar panel - hypothetically infinite joules/kg So as a power source, batteries are woefully inadequate.

Nah they already tried that with milkyway bars and nobody eats those anymore

Then Im gonna make a huge profit on this bushel of apples.

@MatterBeam I did say this would boil down to the usual arguments for/against stealth-in-space! Dont get me wrong, its probably the most effective concept for stealth-in-space that I have ever heard, but it has too many holes, and stealth-in-space butts up against too many physical laws for me to think of it as anything other than another increment in detection difficulty. That stealth can be incrementally improved was already a given. The physics and maths of the cooling you describe, I’ll gladly agree that is a significant increase to stealth, though in reality perhaps not as great as one might wish. The core tenet still stands – there is no [absolute] stealth in space! I mean, when you look at it typed out like that, what does “absolute stealth” mean? It means total invisibility, which everybody already knows is impossible - at least in terms of macroscopic amounts of normal matter. What the core tenet is supposed to mean is something more fundamental – that due to physical law, stealth will always be imperfect and thus open to detection. Even if todays IR detectors approach maximum possible sensitivity, your target will always be radiating and thus in principle at least, open to detection. And Im still really skeptical about the invisibility of that gas cloud… Anyhoo, as someone else pointed out, we are way off-topic. OP is asking about a stealthy atmospheric re-entry.

Yeah, apologies, got the sources mixed up a bit. It still only contains MatterBeams own analysis.

I've answered this kind of thing multiple times with lists of stuff I had on my mind at the time. Today I'll keep it simple - anything by Alastair Reynolds. I love all his stuff, especially the Revelation Space series.

It sounds like you need to peruse project rho (http://www.projectrho.com/public_html/rocket/), it has a great section on the theory of space war in terms of known science and current/reasonably extrapolated technology. Also pay close attention to the sections on propulsion to learn more about the difficulties of delta-V, reaction mass, acceleration and manouverability etc. As you may have gleaned from other responses, your design is more fantasy than reality. The harsh lesson is, your design is full of holes. Its FTL drive is purely hypothetical. Its non-FTL acceleration will be measured in micro-Gees. And it sounds like the full internal volume of the ship will be weapons. The idea of putting in an engine intended for atmospheric use is ridiculously ill-advised. Your armour is made of exotic materials but is still only 8 inches thick, which whilst offering some protection, against a kinetic projectile of any significance (read: starting from a late-20th century tank cannon) its about as good as paper. See this concept for more detail - https://en.wikipedia.org/wiki/Impact_depth - its a simple expression, but it holds as an approximation for anything from bullets to atmospheric reentry. Your thermonuclear shaped charges are actually quite a good choice and are backed up by real science (though personally I've never liked them). But your choice of things like number of "torpedo tubes", ammunition load, point defence etc. feels totally arbitrary. It feels like you are describing a WW2 battleship but with its systems replaced by sci-fi alternatives. Thats like designing a car by starting with a submarine, sticking wheels on it and asking if it seems like a good design for a car. (Sorry, I really like annoying analogies ) If you read through the various sections of project rho, you will start to form a new picture of what a "space battleship" (or indeed of what space war itself) might look like, and it will be radically different from your initial assumptions. Also check out "Children of a Dead Earth", a space battleship simulator that tries very hard to be as realistic as possible, with lots of real maths and science. Its not perfect but it is pretty danged detailed.

This is the rub. "Undetected". You mean "Less detectable". The degree to which an object can be made "less detectable" is what is in question, and may not be significant, dependant on sensor technology. I get how it is supposed to work, but a lot of your hypotheses depend on 100% efficiency here and there, you cant just shunt energy around wherever you want like that. Nobody is saying you cant make a spaceship harder to detect, only that there are hard limits to what you can achieve. No amount of hydrogen cooling will render the skin of your craft literally undetectable. For example, you have cooled your reactor with LH2. Now you have very high pressure (because you cant allow it to expand yet) lines running through your ship at 3000K. Those are an internal source of heat now too. You havnt sequestered the heat, just moved it. How do you insulate that plumbing from leaking heat into your ship? More cooling right? Your maths all adds up but it illustrates a very simplified approximation. You are using active (energy-consuming) techniques to cool the surface of your ship, collect heat from other parts of your ship and dump it overboard. No part of that is going to be 100% efficient (and worse, there will be feedback loops - you didnt take into account the heat produced by your heavy duty refrigeration equipment.) meaning that the skin of your ship is going to be a lot warmer than merely equalising both sides of an enthalpy equation suggests. I dont doubt that an LH2 heatsink can make the skin of your ship nice and cold, but its not going to be as cold as you make out, ergo, not as undetectable as you make out. And the enormous gas cloud is still the elephant in the room if you ask me. As far as stealth in space goes though, its probably one of the more convincing regimes I've heard of, you should send it in to the guy at project rho, see if he has anything to say about it.