wumpus

While the vacuum Isp of propane and N2O isn't that bad, I'm less convinced of the sea level performance. It might need some boosters. I wouldn't underestimate what a photodiode can do. A quick check of digikey showed plenty of photodiodes that wouldn't be a limiting factor, and a cheap and available had 7.5ns response (it should be higher than you sampling rate needed to filter out the vibrations, actual change in position is trivial compared to that). I'd expect an array of much more than 4 would be needed (wait till the lens/canopy warps due to maxQ pushing it around). I strongly suspect that off the shelf options are out of reach, unless they are some sort of side-hobby of the manufacturer. The volume for this type of thing is just too low. I imagine the huge issue would be getting something that would naturally filter/accumulate the vibrations that happened in each sample (further filtering isn't hard, but you really need good samples: you could combine analog filters with fairly high sampling and have great data from those photodiodes). I'd be more concerned with trying to do avionics at high vibration, perhaps you would have multiple engines and throttle the oxidizer in a specific direction. I suppose I've heard of a few launches exploded due to guidence failures, but even more engine failures. I'm curious why Copenhagen Suborbitals remain "suborbital", and I'm guessing mainly cost. On the other hand, their main goal is human flight, and launching a satellite really doesn't help much that way (they really don't intend to put a person in orbit any time soon, thus the name). It really looks like they are as close to getting to orbit as Korelev and von Braun were in 1955 or so. [Edit] Scott Manley just released a video: "10 dump space mistakes". Plenty of them were guidance errors, but I suspect a lot of that has to do with Scott being a software developer and knowing "how hard could that be" and also knowing that such software is typically the proverbial straw that breaks the camel's back. Still, I'm more familiar with engine/staging failures than guidance errors causing rockets to fail/explode/be exploded for range safety.

It can carry ~400,000lbs loads with little envelope issues. You will have significant carrying/hardpoint/harness issues, along with a need to build a fairing (which might get used plenty of times if you are boeing/airbus). I'm guessing that anyone using this would have extreme envelope issues. NASA considered building something like stratolaunch to carry the shuttle, presumably before a 747 was qualified.

I suspect the difference between the two is not the complexity (we've seen enough wheels on a plane that you could probably "simply" put a tread around them) but the failure modes. Lose a tire/wheel and you barely notice it (well, not the Concorde, but I'm sure they put that many wheels on sturdier aircraft). Lose a tread and the plane crashes. It certainly would be more complex to have a tread. But I'd be a lot more concerned with the difference in failure modes. I'd expect that doubling the number of wheels would spread said complexity around the aircraft in terms of increased mass (I'd expect the bracing needed to support the extra mass is "complexity" as well as the more powerful engines), but that is worth it to trust your landing gear.

While there is nothing to make air launch liquid fuels unfeasible (X-15 did it), Orbital ditched that idea and moved to a three-stage all solid rocket on PegasusII until it was canceled. Hydrolox is particularly bad for air-launch use due to the need to keep topping up your hydrogen from the mothership (you would do the same with oxygen, just that you would need to supply so much more hydrogen). The four engine "Falcon Air" was presumably sized for the Stratolaunch, simply scaling up the size isn't likely to fit. Don't forget that this was based off the Falcon 9 1.0 and essentially impossible to recover (they were planning on parachutes). With ground launch, Spacex has steadily scaled up the Falcon 9 to include both recovery and doubling the payload while increasing the total mass by 60%. I would assume that anything launched by stratolaunch would have no ability to scale up the mass/size. The obvious issue the stratolaunch backs itself into is that it strictly limits the size of the satellite it can launch, while still requiring basically the same number of flights to design the rocket as the big boys. The Delta-II was able to scale itself by adding various numbers of SRB boosters ("more boosters") and the Delta-Heavy and Falcon-Heavy "simply" combine boosters to build a vastly larger rocket. These are then more efficient and can lob large numbers of "stratolaunch sized" satellites into orbit even more efficiently than a small stratolaunch rocket even with it's 50% efficiency. Note that how this thing gets to Mars is only one of Elon Musk's concerns. Recovery is a particular bugaboo of his, and it isn't clear that spacex could use current recovery methods to recover Falcon Air. But the real reason Spacex still exists at all is the CRS program. CRS requires 2-3 tons of cargo and is delivered by a 2 ton dragon capsule. If Spacex was tied to Falcon air and couldn't cut the dragon down to fit the falcon air payload requirements, spacex would go bankrupt. Just from memory, CRS is one of the lightest LEO payloads falcon 9 carries (excluding multiple launches), and I don't see how they could afford to justify falcon air without CRS. Remember: all this is to simply justify the *rocket*. Justifying the Roc is pretty hopeless, and pretty much is all about wondering if anyone will bother to pick it up after bankruptcy. I wouldn't be surprised if Airbus or Boeing picks it up as a "guppy replacement" cargo plane and drive the price out of consideration for a company like Orbital (assuming the Pegasus II could be justified at all).

Since as Steel mentioned, the stuff simply doesn't interact with the electromagnetic force it is next to impossible to get it to show up in the LHC. It might be interesting to take the assumptions of "how much dark matter is in the universe" and try to take an inventory of what the LHC produced. Is there enough "missing mass" to match the expected amount of dark matter? I'd assume that the LHC has *zero* missing mass as that would be the discovery of the century (either as a conservation violation or the observing the creation of dark matter: take your pick). This leads to the question of why this thing doesn't make dark matter when it appears to make everything else. As mentioned in this thread, gravity is unbelievably weak. If the LHC creates dark matter, we aren't going to detect the gravity it produces. Try to remember what it took to detect gravity waves: colliding black holes. We need to detect subatomic particles in LHC (probably with relativistic mass, but still impossibly weak forces). Maybe somebody can detect it via nuclear strong or weak forces, but they don't interact with the electromagnetic and gravity is just too weak (and nobody has any idea if dark matter interacts with the nuclear strong or weak anyway). It is hard to tell, but I think "dark energy" is a bigger finagle factor to existing equations than "dark matter". Comparing them directly would be apples and oranges, but it seems the "dark energy" is the greater mystery, but doesn't get nearly the ink that "dark matter" gets. Count me as one who thinks the whole dark matter/dark energy looks more like the "luminiferous ether" than "Pluto", but I'm only qualified to talk about the history of said science, not the actual nitty gritty of the equations (and not much at that. But considering how well my history of science professor botched chemistry...)

Depends how high. This was even done (go out and loop around the moon to position a GSO satellite) in real life (around 2000 or so). Obviously this is only a serious option if the "revert to launch/assembly" is grayed out and you have plenty of delta-v left on board.

I hope you realize that the campaigns are a bit of an alternative to career mode in the game. I really doubt they have been updated while drastic changes have happened in the game. Some general principles: Be ready to skip anything that doesn't appeal to you. This is one of the main advantages to the campaign over career mode. Don't take early rocketry too seriously. Since you can't set a maneuver node on a pad, hitting a specific place with a missile is harder than it should be (especially for starting out) Rendezvous and docking are harder than landing on the Mun (and Minmus). Since they are unneeded for these feats, they are included in the campaign due to historical events. If you aren't playing with realism overhaul (and thus need Apollo-style missions to the moon), I'd skip them until after landing. I'm glad the campaigns haven't been entirely forgotten, they gave me a great place to start before even "science career mode" and are better in many ways to the current career mode. Just don't expect everything to play well with 1.3.0 (and no, you couldn't include maneuver nodes from the pad then. I wouldn't be surprised if "kerbal rocketry", including hitting separate islands/continents, was written before maneuver nodes existed at all and has merely been copied ever since).

I wonder what type of odds I can get for a teapot...

Depends how you look at general relativity. Einstein''s point wasn't so much that they were equal experimentally, but there was no possible experiment to show that they could be different (i.e. "are you in an accelerating elevator or a gravitational field?"). If you want to claim they are different, you still have to overthrow/replace a lot of general relativity. The whole basis of the thing is that not only that special relativity was true, but that inertial mass is gravitational mass (or gravitation fields act as accelerating fields of reference and all physical laws still hold). Einstein assumed they were the same ( " ") and worked out how that would affect physics. He called those effects "general relativity". If they aren't the same, somebody is going to have the enormous task of creating a substitute with nearly similar results that could replace general relativity.

My initial reaction was that moon rock made a better rocket fuel (in the sense of at least easier to get to) than inside Earth's gravity well, but a little googling said it wasn't remotely that easy. I'd expect that at least some asteroids will provide the right chemical structure to be converted to rocket fuel, but expect to big orbital processing plants with nuclear power. Your path to GTO crosses through the Van Allan belts many times, and this can be an issue for the solar panels (especially if you are using VASIMIR to recover your orbit after a dip into the atmosphere). A ferry that can move fuel from LEO to LTO/L2/similar for low fuel cost (high Isp) regardless of speed can "break" the rocket equation even for low Isp/high thrust crewed missions merely by moving chemical fuel on the cheap. Get that part working and you can build up to scooping oxidizer later. Don't forget that while hydrogen is an ideal fuel from Earth to elsewhere, it is a lot harder to store for the trip from elsewhere to Earth (hydrogen leaks through *everything*, although presumably the system the James Weber telescope can store liquid hydrogen almost as well as it can store the liquid helium it will carry on its mission). Don't obsess to much with the fact that Earth has an abundant source of oxidizer that isn't even locked in a molecule. It still is awfully deep in that gravity well.

The unity of gravitational and inertial mass is the main point of general relativity, and it has been proven remarkably well. I doubt any update of general relativity would be able to separate the two forces.

I'm sure a screenshot would help, I suspect that there are bugs in this training session (I suspect that coding certain checks has a lot of problems). I've been unable to complete the session, but may have not followed the exact proper sequence in putting on solar arrays and batteries. - note the "expected" rocket can be seen in the "to orbit" training session. That might give you a better idea of what they want.

My understanding that during the last days of Mir, fire was a constant threat (and cosmonauts spent a great deal of time fighting the fires). No idea if this was a large part of the problem.

That only works if the failure modes are completely independent. Testing the LES at maxQ mostly confirms that this should be true, but there are always possible failures that could destroy the LES.

Either you didn't read the hints or something is really messed up in your installation (likely, I know I couldn't do this with one of mine around 1.0.0). If you know how to set the tracking computer to the target, all that you could have gotten wrong was not going full thrust when told. But I couldn't complete the "advanced construction" training. I must have put something on wrong and it never believed I had properly rotated solar panels and batteries. I didn't even look at the docking training. They don't even break up rendezvous and docking? [Career rescue missions are a great introduction to rendezvous]. I also can see someone new not reading all those texts. You need to know everything in there eventually. But it might be easier just to watch Scott Manley. You can speed up time by using the ">" key (and undo it with the "<" key), but these are disabled in training missions. Considering how long it can take to wait for a capsule to fall back from space, it is often better to practice these types of things in sandbox. One thing that helps in the training mission is the little target indicator in the orbital mission: while it shouldn't be needed to for suborbital hops (straight up should work), it is an important path to learn to get into orbit in KSP (and I don't know if mechjeb will give you as good an indicator or not. You can't get one in stock KSP outside of training).

Legend has it they rung bells at thunderstorms. Laws had to be passed and bell ringers forced to avoid ringing bells to avoid death. No idea how accurate that one is.

One option is skipping the career mode and going straight to the sandbox. One problem the sandbox has is that it makes all the parts immediately available. You could avoid this by playing the demo, which has the added bonus of being able to hand the demo out at the library. This thread points to the current location of the demo (it is under maintenance and will be replaced with a new 1.3.x demo shortly). I don't have KSP on this system, so can't check the state of the training (I'm not at all familiar with it, it didn't exist when I was learning the game).

This only matters if it creates a [new] maxQ or your engines and cargo (especially astronauts) have issues with acceleration. The structural supports will bear a weight equal to the thrust of the rockets, and the actual mass & acceleration simply fit the needed ratio. Of course if your balloon fuel tanks supply more support when full, this could be a problem. But it doesn't add support issues by losing mass. The above post was where I derived an equation for efficiency TWR vs. velocity of the rocket. As far as I can tell, there's no reason throttle unless you are approaching terminal velocity. This was a big thing in pre-release KSP and the "souposphere" but now only likely considered for places like Eve, Venus, and any gas giants you get too close to. Furthermore, you are almost certainly not reaching these speeds in a liquid fueled rocket, so you would be "preshaping" the solid rocket boosters to reduce thrust to avoid such high speeds at insufficient altitude. That leaves reducing maxQ and reducing max acceleration (especially for manned flights and delicate scientific flights). And probably things like "rely more on rockets you will stage first and less on fuels you will stage later" and other efficiency issues directly related to the rocket equation.

There is an interesting option to massively boost any "milestone" bonus at the expense of drastically cutting any bonus from contracts. It does require significant prestige and other requirements to even have the option (google it before seriously trying to gather the costs). The time I tried it I wound up botching the game a bit after that, so I really don't know if it is worth it (playing with such limited contract rewards gets scary). But I like aiming at milestones so much more than contracts that I thought I'd try it.

"Having to pay your workers" has a lot to do with how much you have to refurbish your reusable rockets. After all the Shuttles were made, NASA longer had to pay those contractors to build shuttles. They did have to pay the refurbishing crew to keep repairing them each time they went up (and don't ask about SLS existing to keep them on the job). In spacex's case, presumably the workers who used to build falcon 9 boosters will be building the next generation rocket, and the assembly costs will be lower. As long as you don't have refurbishment costs, reusability doesn't matter no matter what your launch cadence is. If they are shuttle level, you are in trouble. While I'm skeptical of spacex recovering the second stage, I'm vastly more skeptical of it ever being a "gas and go" recovery. Expect them to need a lot of workers regardless to either build or refurbish second stages. To a large degree I think we are talking past each other. Certainly they should be able to reduce costs by launching more often with the same army of workers. I've been wondering if they have such a large army of workers because "that's how NASA has always done it" and that as Elon Musk burns them out, they shouldn't be so quick to replace them, but to find ways to reduce that army in ways NASA has never needed to care (not that NASA's budget is so big, just that the other costs overshadowed the launching costs). Blue Origin appears to have hired most of the people who have looked into this.

Falcon 9 was designed for parachute landing. Falcon 9 1.1 was redesigned for powered landing. Falcon 9 FT finally landed (or at least a landing happened after launching the first FT). So it was designed when they didn't really know how it was going to land (and this really hits the delta-v split between upper and lower). So until spacex (or blue origins) finishes a design on another orbit capable rocket, we really won't know what something reusable will look like that lands as it was designed to land (at least other than the Space Shuttle). Spacex offered about 60% of the price off for the first reusable rocket I doubt the rest will get such a great deal. NASA spent a ton of money (government accounting says $450,000,000 a launch (2011 money)), but the spent a lot more than if divide the whole program by the number of launches. I'm certain there are a lot of costs to find and replace with cheaper methods without the huge price of the rocket overshadowing everything, but they have only started on that. Finally, I'm not sure about "transition" between expendable and reusable. It manages to reuse ~90% of the rocket, I'm sure that the "shuttle" (orbiter, fuel tank, SRBs) was less than 90% orbiter (the reusable bit). Getting that last bit down appears *hard*, and not necessarily the largest remaining cost in launching a rocket.

This seems to be outdated advice from the days of the "souposphere". Outside of somewhere like Eve, it shouldn't be possible to hit terminal velocity. It does, however, give you a great way to measure aero losses: terminal velocity = 1g of aero losses. 2*terminal velocity = 4 g losses (drag increases by the square of velocity). The catch is that a rocket shape has the least drag possible for a given mass, and terminal velocity will get high pretty fast, and keep increasing as the atmosphere gets thinner (so you don't lose a lot of terminal velocity if you stage in the atmosphere). So if you somehow managed to accelerate to terminal velocity, TWR=2 should keep you there (but you will only accelerate as fast as your terminal velocity drops. It would take an extreme atmosphere for this to be an issue (Eve, Venus, or "souposhere Kerbin". Certainly an outer planet if you got low enough). A naive attack on the Goddard problem: acceleration=a (in "gees"), v=velocity (speed really, I'm ignoring direction) VT=terminal velocity TWR=thrust to weight ratio. e=efficiency, theta = angle of your prograde velocity (cos(theta)=1 until you start your "gravity turn"). a=TWR-cos(theta)-(V/VT)2 e = (TWR-cos(theta)-(V/VT )2)/TWR I suspect that this will have to be solved numerically, but at least it will likely tell you that you can keep TWR arbitrarily high below terminal velocity. In reality, maxQ (and max acceleration your crew and structure* can withstand) will limit TWR, as well as cost (especially if you are using liquid engines). * note that the total weight of the rocket on the structure shouldn't increase beyond max thrust at full fuel no matter what the acceleration of the rocket. Thrust = ma and the total weight = ma, so weight = thrust.

I doubt you would find the differences between most editions interesting, but here is what is out there: 1.0.0->1.3 pretty current (although I'm sure the language pack is huge for those who want it). I'd expect that much of the newer editions mainly fix real problems. beta (presumably on steam, I don't remember seeing the option): pretty much the height of the "old KSP". Anything you could do before this is likely possible in this edition. It has the "old aero model" which means that pancake shaped rockets typically work better than rocket shaped rockets. Optimal TWR=2 for most of the souposphere (go straight up for 10km, turn 45 degrees East, burn till ap>70km. Circularize at/before ap. original demo (and before, these should be available in the above links): extremely primitive, expect to learn a lot about asparagus staging and using cans 'o boom. Same souposphere. Note that trying to match a mod to an ancient version might not be worth the time and you will likely be stuck with stock (and possibly digging through a "must have" mod or two).

Don't expect much in the way of names, although descriptive names are good if you need to find an old one (I need to learn this better). Some typical names: rescue rocket (obvious) love boat (for tourists). Older kerbanauts (or perhaps those subjected to 1970s US TV reruns) will get this munsmoon (for "place a satellite in mun's orbit) cheap launcher (for "place a satellite in Kerbal Orbit") munshot - for crewed mun missions Skylab (initial space station) Note that you can rename vessels, but I typically give the rocket the name I want the result to end up with (for things like satellites and space stations). It makes it easier to find the right launcher in your save file.

If you plot the percentage of Space X flights, according to a continued graph they would presumably be responsible for all of them by 5 years. The real catch is that I suspect that for various political reasons, at least 50% of the existing rocket market simply won't use space-x (or blue origins should they provide reusable launch services). Should gnet (or whatever the joint google-spacex satellite internet service calls itself) really require (and pay for) hundreds of launches, single stage reuse (or 1.5 stage, but I suspect they won't use falcon heavy) will be "most". But to maintain their expansion rate, spacex is going to have to find new people that want to launch satellites (and have tens to hundreds of millions of dollars to do it). Expendable and full stages are possible. Engine only is only on the drawing board, untested, and doesn't have paying customers. I'd expect spacex to test upper stage recovery, but more as basic research and testing methods for later rockets, not for actually recovering falcon 9/heavy upper stages. But considering that the falcon 9 probably recovers more rocket by mass than the space shuttle, I really shouldn't count spacex out (but I will. And I certainly don't expect many non-spacex rockets to be recovered. Finally, don't over emphasise recovery: the space shuttle introduce recovery to the space industry and still cost $450,000,000 per launch (or more. The whole program cost more than a billion per shuttle flight). You could easily get the same cargo into orbit cheaper using disposable rockets.