wumpus

I remember a description claiming that blasting a piece of PVC was a good way for cubesats to move around. I think the idea was to vaporize the PVC (not quite as advance as turning it into plasma) and use that as rocket exhaust. Presumably using an electric arc to vaporize a bit of PVC.

It is entirely possible that the Great War (WWI) solidified poor "best practice" in aircraft design. Aircraft went form wildly experimental to engine in front, one set of wings (as the biplanes slowly died) somewhat behind the engine and a tail at the end of the fuselage. A lot of great ideas where put aside to standardize on this form. I'd expect that the modern explosion of computing and communications (especially the internet) had a technological increase that put WWII to shame. Moore's law holding for nearly 50 years of exponential improvements is not something that even a prolonged war can match. While some may point to the Cold War as a great example of military spending pushing tech, it might help to look at exactly how (at least in the US) defense systems were constructed, especially compared to the commercial world (which was busy obeying Moore's Law). The defense world was controlled by MIL-SPEC, and had to use MIL-SPEC parts. These parts required a full bureaucratic system to allow anyone to use such a part, and couldn't be improved without a similar bureaucratic approval. Once a manufacturer was certified to manufacture such a part, there was little reason to drop the price. By the 1990s, the US had completely dropped this system for COTS, which was building defense equipment from off the shelf parts and then using whatever engineering needed to meed the MIL-STD requirements (basically hit the equipment hard enough to know if it survives a wartime attack). The timing of this shows that by the end of the cold war, that instead of the massive DoD budget improving the commercial world, the "tail was wagging the dog" with the DoD having to buy far more advanced commercial products if it wanted state of the art equipment (and them try to get them to pass MIL-STD). - PS: This was my first taste of design engineering, and I did this between 1997-2001, so have some idea how it went... The US Civil War seems to show little advancement on the battlefield, but I suspect that the logistics experience (especially in the North) provided plenty of ready-made executives for gilded (and pre-gilded) age corporations. While there *were* repeat-fire rifles used in the war, they were used pretty sparingly and only for the biggest attacks (you *really* didn't want to be issued one). It seems the Indian Wars had much quicker advancement in rifle design, quickly working toward a repeating (and rarely-jamming) Winchester Rifle. I'm guessing that the US Army bought rifles in smaller batches more often during the Indian Wars, and wasn't as picky about specific requirements (Civil War rifles were likely stuck with the Minie ball). -- Note: most of my Civil War knowledge comes from tramping around battlefields somewhat near Washington DC. I'm sure other members of this board have far more detailed knolledge).

As far as I know, the most widely used alleged "bug free" program out there is TeX. TeX is a relatively small program (at least compared to modern games) and written by a single computing giant (Donald Knuth) and basically not updated with feature after feature after finishing it. You might look into exactly what it took to make TeX bug free, and how impossible it would be to map that to KSP (although lack of further updates makes it theoretically possible, just that it would involve an infinite number of further bugfixing updates). There might also be small bug-free in the industrial controls world and similar places. That said, the code in Boeing 737-MAX is likely "correct" in that it meets the spec, it is the spec that is broken. So many "bug free" programs out there might well be "broken at spec" while faithfully executing the spec. Bug fixing is a great goal, just don't count on getting rid of a significant amount of them (you'd have to fix Unity as well).

Asteroid steel seems the most obvious, although if you have enough time and solar power, lunar aluminum would make sense. I'd assume that for a long time, off world hull construction would be for spaceships were shielding is far more important than mass, so hollowing out an asteroid would make a lot of sense. "Those with 2g or higher." Sorry, chemistry doesn't care a hoot about gravity. Forging might be easier under some considerations (although probably not others), but you really don't want to build you hull in Earth's gravity well, let alone something with a 2g acceleration. Space construction will be done in zero-g until energy (and lifting into orbit) is essentially free.

I'm pretty sure that the higher (and therefore more volume "consumed") the satellite is, the less likely it is to hit anything. I suspect requiring insurance to cover anything you hit (the FAA required Spacex to have plenty of insurance just for the "hopper" test) would have the actuaries get the real requirements much closer to reality. Of course, this is more how the USA works, not sure if other countries would be interested.

Not a siege tower. There's no reason to make a space elevator roll, and typically (anything not due East or West) will have poor consequences. More like a defensive tower than an offensive one.

One thing you seem to ignore is the shear size of an Orion. You could make an unmanned one small, but in general both the pusher plate and the rest of the vessel require a lot of inertial mass. Think roughly the size of a WWII battleship (or small modern carrier) and you might grasp the size of these things. Putting it on magnetic rails and zipping it off to space is clearly off the table. Who knows, maybe someone may try a fuel-air pusher plate done at a small-scale. According to the last thread that eventually became a pusher-plate thread, that may be possible (at least for the first stage, you'll need a more conventional vacuum stage after that).

As far as I know, SpaceX exists entirely as a service company. Blue Origin may sell rocket engines, but as far as I know, SpaceX only provides launch services. I only hope that doesn't bleed over to Telsa, he has enough communications issues there without using "ship" to mean anything other than delivery cars (and later trucks).

All I've heard is that it is smoke and mirrors plus a few protocol changes. The "new frequencies" simply don't have the range to be used as normal cell tower frequencies, they are more like wifi ranges (mostly thanks to also being absorbed by water molecules).

Sorry, they left out the actions of the magnetosphere when making those calculations. All the residue from all the nuclear explosions within roughly geosync orbit will come back to Earth (of course that means safer isotopes than when the bomb went off, but they are still coming back and wrecking havoc on Earth). You can mostly ignore that by polar launches (i.e. launching out of Antarctica), but launching out of the Mohave is a no-go. And you aren't landing an Orion, unless that "bomb ignited with a laser" works a lot better than the NIF can do. In general, the energy of nuclear weapons don't scale much with cost, so you might as well use the biggest bombs you have. And that means a big Orion. And that means landing is right out (nevermind that it means all residue fires straight to the Earth instead of the other way around).

Oddly enough, the turbo-compound engine were also in considerable use in WWII. The idea was that you used the exhaust from your piston engine to drive a turbine, which helps drive the propellers. This increased gas efficiency and ("brake specific horsepower") and thus range, at a cost of extreme complexity and maintenance costs. Simplifying the whole structure into a turboprop was a big driver in that direction. My understanding is that the real driver for buying a turboprop over a piston engine are the maintenance costs (A&R mechanics are expensive). Increased fuel efficiency is great, but you save more on longer time between overhauls. I would assume so, at least until Material A was heated to a uniform temperature. Until then, the rest of the bar on material A's side will act as a heatsink drawing heat away from the connection point. As material A's temperature increases this effect will get less and less (to the point the effect may switch, as material B's side will remain cold but is a lousy heat sink). Warning: I have no formal education in thermodynamics beyond learning enough in physics class to understand the Carnot cycle. On the other hand, One blue three brown (a great youtube channel devoted to explaining math) is doing a multipart series on the equation that governs the topic you are asking about

Nuclear thermal rockets were giving Isp (via heating up hydrogen) of 800s in the early 1970s. I've heard that Isp ~1200s should be viable now for NTRs. Metalic hydrogen would have the same issues, and could be cut with LOH to get the most thrust for your given metalic hydrogen (at the cost of Isp). I'd hope that's enough to get you a SSTO. I wouldn't ignore fuel-air explosions. It would be a quick and dirty means of getting an air-breather up. The real issue is that an air-breathing Orion SSTO isn't just going to LEO, it has to go to basically LTI (not really, but the difference in delta-v between where the magnetosphere ends and escape velocity is pretty small) before firing up the nukes (assuming you can convince people to let you put them on board). Does LOH even work as a fuel-air bomb? I'm pretty sure you could get kerosene to go boom, but I've never heard of LOH (probably because chemical Orions would be the only reason you would try it). You should also be able to spray the LOH in such a way to get a highly effective shaped charge toward the pusher plate. The two real contenders for "first SSTO" would have to be a space elevator and an Orion. Once space elevators are built, I can't imagine much R&D wasted on SSTOs (although you might get enough Isp that it would be a non-issue someday). Of course, space elevators easily require as much unobtanium as any other SSTO, but simply have more return on investment than any competitor. The Orion could be built by anyone who really wanted to explore space directly and had the political backing to do it. Metalic hydrogen might squeak in, but I'm guessing early reports were overly optimistic.

Belly lander? Any particular reason? Or just make a Starship-like rentry a wee bit easier (except you'll need much more powerful landing rockets for your Earth landing). Non-nuclear bombs? You get a lower Isp/less energy than current rocket fuels I'm afraid, the chemistry simply works that way*. The exception would be using fuel-air bombs behind a pusher-plate. They would have "less Isp/energy" than current air-breather fuels, but that can still be stupendously high (it better be, you'll still need tons of dry mass on any pusher plate). Nuclear power without a pusher plate? Not enough thrust to lift off. Except they both look wildly different than 20th century "AC" and "DC" engines. I suppose that old-fashioned electric motors would still make some sense (for AC motors less than 20hp and DC motors where you don't care about longevity or efficiency, and even less power maximums. As in you won't pay more than a few cents for a modern DC engine controller). Induction engines work far better if you create the AC on the fly (in a way that looks just like making a DC power supply, except you can also produce current going the other way) and "DC" motors typically have the "DC" provided in exactly the same way (except it goes directly to the magnets instead of creating the magnetic field via induction). Supposedly you should be able to create a pulsed jet with no moving parts (I'd assume it would only work in a narrow airspeed range), and that could be used in the modern world (and require some extreme supercomputing to develop). Otherwise I don't foresee pulsed jets being practical (even then it probably wouldn't be all that practical. Probably too noisy for general aviation, too inefficient for the big boys, and only useful to model aircraft makers who really want a jet engine (which is were I'd expect to see classical pulse jets anyway). * the difference is power vs. energy. Bombs deliver a great deal of power** all at once, while convention fuels take awhile to burn (until you add LOX to the mix, that's the reason rockets can explode). Also bombs have to contain their own oxidizer, which is typically lower in energy density than LOX). ** I doubt my physics teachers would approve of defining power in a way that ignores work, but assume a pusher plate if that makes you happy.

KSP 2.0 is said to still be using Unity, which implies less hardware requirements than your typical AAA game. No idea if they plan on replacing the physics engine (almost certainly not if remaining on Unity), but that would at least give them the options of using double precision and more threads. I'd assume that you want a few cores (although an i3 with 2 cores and HT might be enough) and a fairly high clockspeed. If they want to include the colonies as shown, there will have to be some drastic changes to the physics model. No computer designed could run that many kerbal objects through the unity physics engine without grinding to a complete halt (I'd assume that anything planted in the ground will be "physicsless" until something bumps into it: presumably any crashes would use a model similar to crashing into KSC).

Eh? I've often heard this argument (although it isn't quite as bad as movies "ruining" the book). The old game will still be there. Of course, as a Steam game I'm only hopeful it will still be for sale (and considering the $60 price, it may well not want the competition). The best we can hope for is a last stable version with a more or less full suite of mods (that last bit is critical, if the modders all jump on the hype train while Squad slowly updates KSP 1.x, we could have a highly fractured community all over the map (depending on which mods you won't upgrade without). This isn't an online game. You can still go to Duna even if everybody else is on KSP 2.0. You can still go to Eve (but you still can't lift back off) even if Squad/Steam turns the servers off (thanks Squad and Harvester for that traditional lack of DRM). The retro-gaming movement has shown that good games still have life in them no matter how far the industry has moved on. There are three basic possibilities for KSP 1.0 after release of KSP 2.0: 1. KSP 2.0 completely fails, community keeps KSP 1.0 alive (highly unlikely but it has happened. I think Asheron's Call 2 died a few months after starting. There must be other examples...) 2. KSP 2.0 is merely adequate, forking the community to various degrees. KSP is a great game: trying to capture lighting in a bottle twice (with completely different developers) is going to be tough. While KSP has many places that need serious improvement, I'd be shocked if KSP does the sandbox quite as well, and that is what makes and breaks KSP. 3. KSP 2.0 is clearly superior, and the community moves en masse to KSP 2.0. Actually I assume that all new players will start on KSP 2.0, so Steam statistics will probably show this to be the case regardless while any grognards clinging to KSP 1.0 will clearly claim that case #2 is "obviously" happening. In any event, KSP 2.0 will likely both need new mods, and have more obvious places that need expansion, so will probably get the modding community in any event.

That the US patent office advertises using "shield patents" for reason #3 tells you quite a bit about how broken the US patent (and any similar system) is. Also it's been like this at least through a couple Bush administrations and two Democratic administrations as well, so much of the political machinery holding it together is bipartisan (I'm guessing anyone who can afford effective lobbyists can afford enough patent lawyers to usually get an edge against the competition).

I'd assume a "real" definition includes lift>weight, but that might include the Apollo capsule (the drag *should* disqualify it, but I doubt that is formally defined). I'm pretty sure that it was designed to skip through the atmosphere to a higher orbit and then come down again (all to reduce maximum heating). I don't think that was ever done in a real mission (they angled it, but not enough to leave the atmosphere). Of course, Apollo had a much higher velocity than any other returning spacecraft, so had an amazing lift advantage just by moving the center of mass away from the center of drag.

2020 launch SLS test launch 2022 launch SLS crewed? SLS block 1b test? 2024 launch SLS block1b crewed + unknown support craft Delta IV heavy and Falcon 9 are presumably available for shipping whatever is needed to TLI, but would need a contract *right* *now* to build/integrate the parts for a 2024 launch. Of all the innovations that have come out of SpaceX, why did NASA/Boeing have to pick up "Elon time"?

I doubt they have bet the company on Starlink (doesn't Google have money in it as well), but they have more or less bet the company on Starship, and Starlink is its only current job (although presumably Starship could launch multiple birds into reasonably close orbits at Falcon9 prices).

Used to be the rocket-building interface. The struts still seem to be irrepairably broken, but between autostrut and rigid parts (which I think are stock, I haven't updated those mods in multiple revisions) struts no longer seem critical. Mostly now it is just the way career mode encourages grind. The rocket-building interface (especially if struts are required) has been really *bad* over the years. I felt betrayed when Havester "rewrote the UI" and it turned out to be the inflight UI and not the rocket building one. Not that the inflight improvement wasn't needed and helpful, but it wasn't the UI that I felt was really needed.

Wiki claims the US Navy's Ford Class Carrier program costs $37G to design and $13G per carrier, although it relies on a military industrial complex assuming that such carriers are as critical to homeland defense [snip]. I strongly suspect you could build an Orion with a budget like that, and an Orion would qualify as a "battlestar" by any 21st century definition (even if it is a mid-20th century design). I also think an Orion class "battlestar" could project force significantly better than any aircraft carrier or fleets of carriers (although it wouldn't be able to power stricken cities with electricity the way carriers can). Getting it up to orbit would obviously have political and diplomatic issues, to put it mildly.

On the other hand, the Dawn probe had 10km/s delta-v in its ion engine for use *after* reaching escape velocity. If you have the patience, ion thrusters are absolutely amazing (but I'd expect that you still want to use fancy gravity tricks: ions will simply get you in position for them faster). If your patience depends on the cargo, you can practically break the rocket equation by using ions to move propellant to a depot in the right orbit, and then simply move your chemical-powered crewed rocket from ion-fed depot to ion-fed depot: LEO to escape velocity is ~3000m/s, while going to Mars is another ~1000m/s (and presumably send any return propellant not ISU-generated on the surface via ions as well). Electric propulsion with Isp>1000s is a thing (generally speaking Isp isn't the limiting factor with ion propulsion, if you want more you can probably get it at a price). Remember Robert Heinlein's statement that "LEO is halfway to anywhere": with ions (and especially ion-fed depots), LEO is nearly all the way there (no known way to use electric propulsion to orbit, not to say Escape Dynamics didn't try).

Second hit via duckduckgo: https://atsushisakai.github.io/PythonRobotics/ A quick look at the descriptions of the sample code indicates that robotics is hard, and even python has a hard time making it easy. Of course, you probably don't want most of the hard issues of robotics (determining the local neighborhood visually and navigating around it, or where that car door is that you need to weld) and just have to deal with things that are mostly seen by mechjeb. Accessing the I/O functions are going to be specific to the hardware and "robotics" probably won't be a good search term. Just go through "python", [insert platforms of choice here], and maybe "gpio" (gpio your user controlled output pins). Also look into whatever PID routines you need (developing the parameters is probably much more complicated than writing the code, so don't worry too much about python modules here). As far as Python/C++/C/Java goes, don't be too surprised if you eventually need to drop all the way down to assembler (C *should* work, but you basically need to understand assembler and C to do it) to say this pin needs to be that voltage. I suspect that is what you are asking for, and it will be specific to each hardware platform (arduino, raspberry pi, gumstick, etc.). Good hunting.

looks like the tried and true method is os.system("a.out") while the new hotness is subprocess.run("a.out", "-parameters"). If you are having trouble with python, I'd think twice before trying to tackle C++. It seems that C++ started with C, then added every possible feature they could to the language. Expect to need to know a lot more about the language to do relatively simple things than you ever needed to know about python. I was trying to do exactly that: take an existing C++ library and get it to run in Python. Of course to do this I had to finagle the wrapper functions to deal with the data the way python expects, so it took just a little C++. One of the gotchas was that none of the "learn C++ books" I found at the local library mentioned that the method I was using to create objects (simply typed from "Learn C++ in FIXNUM days") was putting the object (but not the pointer) on the stack (where it would quickly be destroyed), but I needed to put it on the heap instead (I should have known this from simple C programming, but my C was pretty rusty by then). Even this little thing took about a week of debugging (since I really didn't understand the issue).

If "all" you want is an Earth-based SSTO, you don't need unobtanium nozzles, anything that worked with a NTR should get similar efficiency with laser propulsion. That said, Escape Dynamics (the company that tried for 5 years to do this and then went bankrupt) only managed about 500s. You'll need hydrogen reaction mass, but the Isp should get high enough for SSTO. Escape Dynamics' method of "laser propulsion" didn't involve "riding the laser", it instead heated the reaction mass, so propulsive landing (and hovering) should be possible (assuming your valve can withstand maximum temperature for hovering). The lasers are the tricky part, and can be expected to be hid behind a security wall as the US Navy develops them.