wumpus

Also remember that the formula for ISP is pretty much based only on exhaust velocity and acceleration in "1g". So increasing the ISP means increasing amount of heat in your exhaust, which is pretty much already pushing the limit of what materials science can survive (although switching to closed loop effectively "increases" ISP by avoiding losses). For more extreme ideas: Nuclear engines have similar heat issues, so expect *less* efficiency from a water-fed nuclear rocket than a hydrox chemical rocket (which is why they traditionally only use hydrogen). Even if the "em-drive" doesn't work, you can get the same effect (at lower efficiency) by shining a light in a single direction. You could also crank the Isp of an ion drive arbitrarily high by means similar to a cyclotron. Such a thing would be pointless for interplanetary voyages (the Isp isn't the limiting factor) and probably equally silly for interstellar voyages (I would suspect that any such design would get *more* thrust from the black body radiation (with materials chosen to emit preferentially in one direction) used to cool the nuclear reactors...).

How big a gap are you willing to live with? My guess is not as big as the 3d printer will need. 3d printers aren't the magical boxes some people think they are. For this type of thing "some assembly will be required". Also expect that for parts that have to move against one another, CNC devices will routinely produce superior products over 3d printers. - insert rant about how "3d printing" exists pretty much for low volume applications. Try to use 3d printing on a larger scale and a competitor that uses vacuum molding will crush you on costs and manufacturing tolerances every time.

You want Delta-v numbers from Kerbal Engineer or mechjeb. All the ISP numbers are is exhaust velocity divided by the acceleration of (a unit) gravity. They are useful for being the same for metric and imperial units, little more. Of course, exhaust velocity has its own nasty equation with various variables and constants hanging all over it, so expect to look up that (or ISP) in a table. ISP has nothing to do with "bypassing calculus" (or the rocket equation).

If you are already using a computer to compute these things, you can bypass the calculus bits by including the rates of change in your calculation: if a=F/m, then compute the acceleration for each second, while reducing the mass according to how much the rocket engine burns per second. The delta-v you calculate will be the sum of all the accelerations (until the fuel runs out). Expect errors in this method, but you can improve the accuracy by reducing the time intervals you calculate a=F/m over (and of course, divide acceleration by the time interval and any other issues ignore due to unit measures). While purists may scoff at such tricks, this is exactly how KSP calculates such things in game (at least in the "physics bubble"). In practice, just use the logarithm (or Kerbal Engineer). But it certainly helps to learn where they came from (especially if you have to deal with complicated issues such as solid boosters burning out while liquid rockets keep firing).

Most probably the same way modern silicon works. You simply have excess logic/memory and only use the "good" ones. With data this is wildly more effective, since there exist algorithms that can store the "backup" (call parity in the literature, but vastly more effective than the simple parity bits users used to encounter). The chip then reads the data+parity and computes the corrected data (you need at least two bits of parity for every error in data+parity). Last I heard, if you weren't pushing the limits of these systems, you didn't have enough density to be effective. Logic is a bit more basic. Often multiple cores are produced, and only the working ones shipped set to work. The chips in the PS3 were made with 8 cell processors, with one locked out (had there been a defective one, it would be locked out). Note that for space applications, volume is so low that FPGAs are ideal. FPGAs are basically "programmable logic" that include massive amounts of transistors to emulate more massed produced chips (although typically at a cost in speed, money, and power consumption). However in space applications, should one array be fried thanks to a cosmic ray or other space environment nastiness, ground control could ship up a new logic "program" that doesn't use that particular array. Note that "self healing" this way (without re-computing and downloading from somebody with the source and expensive compiling software) would include some rather nasty delays (above and beyond the in-circuit delays already part of FPGA design).

Compare the cost of a small sat to equal coverage by persistent small drone (solar glider or quad copter). Spy sats got big for more than just high resolution. Also while the NSA/NRO/HSA did start a tethered blimp program, I imagine that disappeared after one broke free and crashed in Maryland. Seriously. Check the limits of apatures and lens/reflector size. You can't get around them by building more devices. Generally, the very few groups capable of putting up spy sats prefer big birds, and can presumably limit access for the small ones as well.

I was thinking about tricks already used on Earth (at least my understanding is that there are optically linked telescopes on Earth). The microthrusters mentioned in a previous thread might come in hand (I suspect you would still have to adjust mirrors to accuracy>>wavelengths of light, but it might be possible to simply move the mirror relative to the spacecraft). Hopefully nothing once things are aligned, there isn't any real movement (presumably a solved issue on Hubble). There are also radio telescope arrays as well, but I suspect that uses more straightforward DSP tricks.

This tends to be assumed (although plenty assume paleolithic), but it is rather hard to verify. We can verify that some humans have genes that evolved (or at least spread) during the neolithic era (I carry genes which allow me to be lactose tolerant, that wouldn't exist in the paleolithic era). To be honest, I'm not sure that evolutionary pressures in a medieval village were all that different from a neolithic one. There was a shocking amount of change (at least in the west) from 1800-1900. While technology since then has been spectacular, most modern people could probably get by (the technology if not the culture/politics) in 1900, but would be lost in 1800.

Mirror (or lens) size is still crucial to telescopes. Miniaturization will likely only happen in thinness (although a sparse array of telescopes will have certain advantages) and allow for in-space inflation. I suspect that the electronics/optics necessary to link up a sparse array of telescopes isn't within the means of microsats yet.

My understanding was that KSP development was pretty vague (it was originally planned as 2d), but eventually there was a list of things needed for 1.0. The writing was on the wall for a long time, and I knew I would miss the mad science days of steampunk style wedding cakes comprised of huge layers of RT-10s (going to the Mun with stock parts was a goal of mine, even if I had the official copy and needed KE). And there certainly were a bunch of ragequits. They might have accepted it as a cost of releasing for 1.0 but they were there.

The Badlands are roughly on the opposite side of Kerbin from KSC. How do you think they got that way? Why did they locate KSC (and the old KSC as well) there?

This is all true, but I can't help but think there was plenty of support for the souposphere in the community and Squad. While there might have been other ragequit posts over the years, the ones I remember were from the changes in stability from .9 ->1.0, which was not something to be taken lightly. So while a good part of the issue was just how hard it was to write (and presumably Farram not willing to give FAR away) [although wasn't there something called "NEAR"? Were they that hard to write if there were competing aero fixes?], another part was the inevitable unwillingness to break legacy systems. And so the souposphere lumbered on.

You mean like a souposphere? If you happen to have KSP .9 or so lying around you could try that. Just be warned that the souposphere has weird alchemical properties such that aerodynamics depends on individual parts and not the whole. Just kidding, the souposphere was one of the least realistic bit of early KSP (although likely an important hack that made it at all possible and lasted way longer than it should have. Not to mention had its own brand of mad science fun). Don't go there if you want realism (although you could probably play with the density constants and make Kerbin more like Eve). If you want realism, you pretty much need Realism Overhaul in its entirety, KSP had to make a lot of changes to get Kerbin to work, it takes an equal amount to make Earth work.

That's pretty scary (especially since LEO-HEO would be where a tug would spend most of its time). I'll have to look into that (and wonder if the Earth would fry without those belts... although I think it is simply the residue of "stuff that would fry the Earth" trapped by the magnetosphere).

Patents predate that by quite a bit. But often they were a quick and dirty means of giving a court favorite an easy source of income by giving him a patent on (for example) distilled alcohol [actually I'd expect something easier to enforce, but it was vastly more likely granted for 'having the King in (gambling) debt' than for invention]. I suspect that the "founding fathers" of the US gave patents that name out of distaste for them (ok, that is probably a reach, but Ben Franklin wasn't willing to limit his inventions for profit's sake). I'll agree that is what you will find at the patent and trademark office, but I have grave doubts about the practical effects. Last I heard (mostly when outraged in the 90s, so I could well be wrong). #1: "practiced in the art" often means a new BSeng degree, or "unhireably unskilled during a downturn". Also expect a patent lawyer to make the obvious sound obscure #2: This is the real kicker. And it typically means "nothing published describing the invention*." (I'd assume that user- or repair-manuals could be used in court cases). It should be obvious that the patent examiner needs physical proof that it wasn't novel (although I imagine that the level of "proof" varies between examiner) #3: If this were true the West Texas patent court would have to close down. On the other hand, I'd have to assume that patent lawyers very rarely have to stretch to prove this, and few patent examiners worry much about it either. Getting a patent is too expensive (let alone defending one in court) to bother with useless things. #4: This changes rapidly. Public key partners appeared to have patented the "idea of all public key cryptography", something far beyond anything patentable even a decade earlier. Even their very specific equation seemed to stretch what was patentable (I doubt many equations were patented before that). The US Supreme Court recently had to call the patent office on taking common business practices and adding "on a computer/on the internet" and patenting that. * It shouldn't take long to realize that pretty much any legal system of patenting inventions will come down to documentation. So if Welsh's patents a peanut butter and jelly sandwich without the crust** and the patent examiner can't find a published example on such, Welsh's gets the patent. ** The actual product is pretty remarkable and has a shelf life similar to other snacks. https://www.google.com/patents/US6004596 (and apparently they won an initial court case and lost the appeal). http://www.nbcnews.com/id/7432980 Can't remember if the defendant was a restaurant (I must have heard about it between Welsh's early win and the appeal) or an actual competitor. Is changing the title an option? I'm not sure how many allowable things are available for what constitutes a "GMO study" and what you expect to find. Also note that Starman438's statement on "what is a gene" was likely critical in understanding GMO and a great proof that not locking thread earlier was a good move.

True. If it was a one way mission, most of the nukes [technical] problems are already solved, just stage the thing and forget it (possibly injecting the melting core with U238 to make it useless for nuclear proliferation). Reusable nuclear rockets are likely going to be trickier than reusable chemical rockets. Even once you throttle nuclear reactors they are still producing a lot of heat, for quite some time. And all you have are consumables (that kill your ISP efficiency) and [black body] radiators. But if you get a nuclear thermal rocket, the bigger question is do you build (and launch into LEO) a second, or do you keep the first around Earth's "SOI" and not bother with the second. I had been assuming a Nuclear Mars Transport and a chemical means to supply it. But assuming you were only willing to have one nuclear rocket, you would much more likely have a chemical Mars Transport, and use nukes to supply it (the nuclear tug would then pay for itself by moving satellites from LEO to GTO with >800 ISP). If your tug stays in "Earth's SOI" you can probably get away easily with only using hydrogen as its fuel. The big question would be if it would be worth using a second nuclear rocket. Presumably the political issues would have been solved, so while the justification is wildly harder (it won't have nearly the benefit of the first one), it wouldn't be nearly as hard as sell. It would come down to the cost, except it would only 'need' roughly 2000 m/s delta-v instead of 5000m/s (assume the tug is far less massive, has roughly the same ISP (or better, since it only uses hydrogen) and carrying the fuel). You probably would also go out with hydrogen out no matter what brought your fuel*, and water back. Or maybe helium. I wonder how much a balloon capable of containing massive amounts of helium would weigh (especially if you could pressurize it to some pretty low levels. Ultra-thin while the volume increases by the cube and the mass of the empty balloon increases by a square. I wonder if helium can escape from a thin film of mylar. If for some reason you made a nuclear transit vehicle and no tug, then you would have tough issues about bringing the transit vehicle all the way to LEO for refueling. My bringing up ions is never about moving astronauts (that would require solving harder nuclear issues *and* solving unknown ion ones), but replacing the "tug". Such a thing might not be as great for satellites (getting to GTO is slow, and time is money for billion dollar satellites), but I'd expect it to get the fuel in place with a 2 1/2 year schedule (thanks to Mars transfer windows). Of course, you would likely be even more limited on fuels (expect everything to need roughly twice the "shelf life" of the return fuel), but with four digit ISP that can be dealt with. * well not if you used ions. But an ion tug and a nuclear rocket would be require a depressingly long R&D cycle**. It would be like trying to get to Mars after ignoring the moon for 50 years... ** hope not. Since we already have two ion engine craft in space, I'd like to think that a craft capable of moving 2000m/s worth of fuel in 2.5 years is within reach. I'm not entirely certain of it. You might need a couple more to bring the Mars Transporter to ~3000m/s (where the astronauts board) and another one to get all the cargo to Mars (which gives you several years to construct the Mars Transporter while the cargo winds its way to Mars).

If you are doing "supply drops" why in the world would you need to go nuclear? You might need something sufficiently stable for ion transport (I'd like to think LOX is, but the amature rocket favorite rubber + nitrous oxide would be seriously stable), but putting them in place with ion engines lets you laugh at the rocket equation's attempt at tyranny. Nuclear issues go beyond the political aspects of things. You have an intense heat source that requires cooling inside a hard vacuum (and no handy source of expendable heatsink that doesn't kill your ISP): that is not an easy thing to deal with.

Try looking at all the "revolutionary" memory and storage technologies that have been researched over the years (typically involving "3d something"). Nearly all of them had great promise, and could ship power point slides showing just how huge an advantage they had over the current schemes. But Moore's law was brutal. If you had a "1000x" advantage over DRAM, you had better have your product in customer hands within 10 years or memory would have already passed you (and you really didn't expect the *shipping* product to have that 1000x advantage, did you?). And hard drives were actually moving faster than that. And while flash might be replacing hard drives, it is certainly due to superior speeds as they are at least ten times as expensive per byte and unlikely to ever catch up there. I had great hopes that the Intel/Micron "3dxpoint" could at least shove its way into a intermediary buffer between DRAM and flash, but it looks like it just doesn't have the [latency] speed. And that is a tech that made its way to the point of shipping samples.

If you can publish the text string of DNA, you can copyright it (I've linked to a paper describing such in another thread [I think it was behind a paywall, but the title was sufficient evidence for the concept], but it seems to have been a "joke paper"). There aren't any "copyright examiners" like there are "patent examiners", so you automatically get your copyright [and like a patent it is pretty much just a ticket to a legal case (at least for DNA)]. As far as I know, nobody has taken "copyrighted DNA" to court for any decision either way. But since copyright is cheap and eternal, I'd assume that every DNA patent (accepted or denied) already has a copyright. One other argument is that copyright protects somebody from mindlessly or deliberately copying the exact sequence of the genes. Patents prevent anyone from independently re-creating the mechanism as well (something copyrights don't protect, but proving influence can be tricky). Hasn't the original "roundup ready" patent expired? I think that generic stuff exists: as such we might see soon if genes can be copyrighted.

Any mentions of the downlink device (for this or Musk's system)? I can only imagine a direct to customer system (like Irridium) but other's (in spacex threads) have suggested that it would be to something like a wifi/wimax link (which would make it harder to justify customers in the developing world). I'd think that getting a receiver (especially fixed) would't be *too* hard, but I've never designed much in the way of RF.

The NSA's primary job is believed (especially by those who have looked into ELINT/cryptography) to be "stealing the codes". Everything else is likely cover for that. If you have the codes, you don't need the physical ground station. Jamming it (and only long enough to turn the antenna) would be enough (I'd assume anyone capable of stealing the codes has their own groundstations).

I think something easier to commercialize would be the electric catapults being used for carriers. Of course, real rockets are unlikely to be happy at anything other than their designed acceleration. Put more force on them than the rocket has and don't expect the sides to handle the stress. I always assumed that rail-gun/catapult->scramjet would be the "launch of the future", but KSP (and forum) has made me suspect that such might even harder than a space elevator.

I'm also assuming that you already slid your slider over to vacuum (not sure how much effect Duna's atmosphere has on the NERV). TWR of .36 on the surface of Kerbin would be *way* too much TWR in space. One old trick to use with low TWR (typically much lower than you are using) is to split the burn to Duna into multiple sections. You could split the Kerbin->Duna burn into two bits of delta-v ~2000m/s apiece. Just set up an encounter with Duna (so the manuever node tells you when to begin) and fire for a burn of 2000 m/s (the easiest and most effective way would be to have a 2000m/s fuel stage). Then set up another maneuver node all over again to tell you how long to burn (the node should be at your new Pe). I wouldn't do this with your rocket (interplanetary maneuver nodes are tricky, and you actually have quite a bit of TWR for interplanetary travel), but keep it in mind if you want to build a bigger rocket and need the efficiency. This trick is often called the Mangalyaan maneuver after the Indian spacecraft that first did it. For Duna, gains are limited after 8 burns (I think Mangalyaan did more) since that last burn is going to be at least 130m/s or so out of a total ~1080m/s. But until you get out to the Mun (which is pretty close to escape velocity anyway) your orbits will be pretty fast (similar to LKO) and shouldn't change your Duna trajectory all that much. Sometime on the forums it is called "periapsis kicking".

First, the elephant in the room is the implied claim that if there exists a GMO food that is dangerous, that somehow other GMO foods should be considered hazardous while ignoring "natural hybridization". They just aren't two independent sets. As far as conflicts of interest, I'd suspect that all the companies with the fancy lab equipment that needs to be paid doing GMO work are doing the research that disabuses the notion that the human body some reacts differently due to GMO insertion, natural mutation, and direct hybridization. The researchers without a conflict of interest are almost certainly going to have far less tools to actually study such problems and might be able to study such effects on the remaining "heritage" seed lines (which are some of the more obvious lines to get a publishable paper that might be less pro-GMO). PS: About the conflict of interest in doctor's offices, while bringing lunch will almost certainly get you in the door, sample drugs are what really influences a prescription. Nothing like being able to hand the patient a bottle of pills and say "take this and refill it if it works". Expect patients, doctors, and "big pharma" to *all* push back if congress interferes with that.

I've heard reports that Skylab astronauts hated exersize, but not the same from ISS. Some of this might be cultural change, but I suspect the newer exersizes make more effort to get the sweat from pooling on your body. There's a pretty good mockup* of Skylab in the Smithsonian (downtown): it doesn't look big enough to run in. * don't know how real the command module body is: I suspect one of the last two was part of Skylab and the other is in the intact Saturn V in Florida. Most things in that museum are the real deal or (for things that didn't come back to Earth) backup copies.