wumpus

I wasn't serious about this suggestion (and have to look up what I was thinking about hydrogen. Something needed a ton of hydrogen replaced in flight, but it certainly wasn't the X-15). The point was that resurrecting dead tech just isn't going to happen: if it wasn't up to the job then, starting from modern assumptions usually will work better: SR-17 - can't be upgraded. Actually I doubt any real parts of the SR-71 have been manufacturable since the 1960s, but bear with me. The Blackbird had issues separating any launched craft, and doing such in the atmosphere has been abandoned. Also while my rule of thumb is that each "3 machs" cut your fuel budget in half (I think it was based on space shuttle delta-v budgets), there certainly isn't room for the rest of the ~20k delta-v. F-14 is dead. So is the Sopwith Camel. I'm more surprised that the F-16 hasn't been put back in production (if all you want is a missile launcher...). The N-1 is a failure. You would need to test the N-1 on a stand. You would also have to have the motivation to go back to the N-1. The most likely to build an N-1 has the motivation to resurrect Engergia (although I suspect they haven't the money for that).

I think the X-15 would make more sense as a cut-price SSTO (or more likely two manned stages where the "launcher stage" would stage from the "final stage" beyond the atmosphere. Staging in the atmosphere doomed at least one SR-71 attempting to launch a rocket/drone). While not only is this "reinventing the Falcon 9", the final parts would be unlikely to reuse *any* parts, nor much engineering. Many early iterations of the shuttle looked like this, but the final specifications drove the eventual shuttle design. Two huge problems would that while the X-15 could handle extreme speed, it never had to deal with full-on orbital re-entry. There's little reason to believe it could survive that. The other issue is that it was insufficiently cryogenic and the B-52 had to pump at least a full fuel tank of hydrogen into its tank* over the course of the mission. Finally, a "scaled up to orbital" X-15 would be huge, probably needing the Stratolauncher to fly (assuming it didn't lift off a pad or take off on a runway). * not sure how much hydrogen was vented directly from the B-52, but the effect would be the same.

If the Russians wanted to go to the Moon, I'd assume they would build the lunar rocket in space like a space station (they certainly have the experience). The economies of scale might work better with a big rocket, but I'd suspect that simple assembly would go a long way and require much more limited R&D spending. This really wasn't an option in the 1960s and early 70s, but I suspect with modern skills it would make more sense than an N-1. Pretty much anything makes more sense than an N-1, although if you could find a way to testfire it, that would let you at least start to make a N-1 work [the thing had to be fully launched to do *any* testing].

Depends where it is. The main cloud you can see close to the Earth is likely to be gone (albeit replaced by new space junk) by the time you send anything up to deal with it. There is also the "graveyard orbit" near GSO that is used explicitly to store space junk (it is way too far to deorbit). In between lies the problem. I'd also expect little cooperation before its too late, and unexplained difficulties getting things to work thanks to three-letter agencies (although Russians may like four) that are hiding military satellites as space junk.

The decent stage was always planned to remain on the moon. Did they "just" use the descent stage during Apollo 13 (for all available burns) or did they use it up and move on to the ascent stage? I'm pretty sure the ascent stage didn't have the fine control the descent stage had.

How many stars [and planets] had to be destroyed to make way for interstellar bypasses? Note that the interplanetary highway is effectively a real thing and works at [more-or-less] human timescales. This thing is for an entirely different sort of entity. I don't think giant sequoias have a lifespan capable of dealing with this thing. If we launched a probe now, odds are humans won't exist by the time it gets going.

The effect is more important with smaller rockets. Pegasus gets a lot more cargo to orbit than you would expect for such a small rocket. If I could pick a place to launch from without political considerations, I'd probably pick some place in Equador: not only high elevations, but near the equator. Cotopaxi is ~19,000ft, and appears to have little settlement due West of it (less true for other mountains near Quito). I have no idea if that mountain has any roads going to/near the top (I'm pretty sure at least one other does, but don't count on either good roads or well maintained buses. And just because the locals can handle nearly 20,000 feet doesn't mean you can).

This clearly depends on the failure mode. The first Falcon 9 had an engine loss that was merely turned off. The N-1 had failures which would damage nearby engines. I'm not sure if Antares suffered a similar fate (watching the video leads me to believe that it lost all thrust after the initial explosion, but without a scale you can't really eyeball acceleration). You basically have to design a device that mixes liquid oxygen with a fuel and convince it not to explode on failure. This is easier said than done. The N-1 tried to avoid this by shutting down on the first sign of failure. In practice, this meant it typically shut down every engine shortly after lift-off, bringing down the whole thing.

I may have been guilty of much of the "can't land the center booster" speculation. It certainly will have to stage after providing a lot more delta-v to the upper stage, presumably going over mach 10 (well, if it were in the atmosphere) during separation for a 25 ton payload and faster with more mass. I'm curious to see how much they slow it down with the back burn (and thus how much fuel they hold in reserve to do so). I'd also expect a three engine landing if they are even considering doing that anymore (it may have damaged the booster they tried it with too much). Spacex publishes costs for full recovery [attempts] and masses for non-recovery launches. I wouldn't be surprised if the cheapest launch costs/ton for Spacex would be a disposable center stage with just the right amount of mass (a fairly unlikely case, but presumably there would be a considerable range below that which couldn't be recovered at all so would take the disposable route and possibly "spare payload"). I expect the "fully disposable falcon heavy" was just thrown out there for the maximum possible mass to orbit. Landing the side boosters won't lower the cargo rating enough that they will ever launch a rocket that they couldn't recover the side boosters.

I'd assume that after Apollo 11 there wasn't much confidence of being able to land in the area previously chosen for a precision landing. I'd still want to send a lander first for modern missions, if at all possible. This type of strategy works better if you are willing to use more existing rockets than build a custom "beyond LEO" rocket. NASA-Congress is stuck with SLS, so that is a no-go. Spacex might have the option of using some similar with falcon heavy, but seems committed to big rockets as well. Russia, China, and India might consider using available rockets (Russia especially after what happened to the N-1).

You do realize that NASA put a lunar lander in orbit around the moon during Apollo 10? And that if you wanted to maximize time on the moon, you could fill one with supplies (presumably not including the command module) on Apollo 12 and land (and use them) with Apollo 13 14? I'm guessing the time constraints were too much (and the computers weren't up to it), but it was hardly on the same realm as your suggestion. For modern missions, it would make sense to use non-man-rated craft to deliver supplies (especially fuel, probably in entire stages) along the route*. Having a lunar ascent module isn't changing things all that much. * "the route" typically is eccentric ellipses with one end in LEO and the other much higher (preferably avoiding the Van Allen belts). Those belts can be a problem with ion-based (read "slow solar-based" systems).

As mentioned earlier, having a rocket on standby on Earth is unpractical (especially for Mars), although it was used with last shuttle flights (which would only have to rendezvous in orbit). A better idea would be to have the lander/ascender already on the Moon. Such a lander could bring more supplies. Note that the lower stage could be filled with cargo that wouldn't necessarily require the same shock levels as the ascender, or possibly have them in separate landers (unlikely to be more practical). The whole idea is that such a "supply rocket" could allow much longer stays while only developing the same sized rocket. Judging by Neil Armstrong's manual takeover of the landing computer (of the most ideal spot for such a landing), 1960s tech just wasn't up to such a system.

My understanding was that LM upper stage failure was the most likely of all imagined Apollo disasters. Presumably caused by landing too hard. If at all possible, I'd try to arrange a lift off vehicle [self] tested and ready nearby the landing site (Moon, Mars, wherever).

A better chance is that the "artist impression" came more from KSP than from the data. Last I heard, these exoplanets are merely seen as blips of reduced light from the star in question: hardly any chance to determine color or composition (although it might be possible to guess size and mass, and thus determine gas giant or M-class).

Keeping even delta-v is typically a better starting point than mass, and probably is rather close to e with stages with the same Isp. I probably grab enough fuel tanks for roughly 2-1, but after that I'm looking at K.E. to optimize things.

Dragon is a fairly light payload for spacex. You may have noticed that the booster returned to land, something that never happens with a full load. Perhaps my "half a payload" was pretty inaccurate, but spacex certainly had more cargo room for that flight.

In this case it is more like "customer paid for the whole rocket, but only brought half the payload". I'd hardly call falcon 9 overpowered, although I'd assume that falcon 5 was originally intended for this role (had they developed falcon 5, landing would be like landing a falcon 9 on three engines without the ability to cut two at the last second). I'd also assume that developing Falcon 5 would have similar costs to Falcon Heavy, which certainly wasn't all that cheap (and have nearly zero savings compared to a reused falcon 9).

Utilization of either CPU or GPU is a red herring unless fps drops less than 60 (or the maximum your monitor can display and you can perceive). If your framerate drops into the "hey! I can see a framerate issue!" then it probably (for KSP) is a CPU (physics engine) issue (and your GPU can simply loaf along and attempt to conserve power while drawing all the frames it gets). Also, it would probably take at least 4 (and more likely some multiple of 4) separate equally large ships all within physics range to make sure all available CPUs (and threads) were processing data. In other words, KSP just isn't going to "efficiently" use all CPU time or GPU time. That type of thing is typical only in consoles (where everybody has the exact same CPU and GPU) and even there isn't likely to work with console-KSP since each space craft is custom designed by the user (and not a developer carefully balance CPU & GPU power). So don't worry about it. Now if you are trying to optimize your system to crank up the graphic options and resolution, or trying to keep KSP working while you make supersized rockets, that is another issue (that is unlikely to be solved by "balancing" or "hitting 100% utilization" CPU & GPU usage).

The other huge problem is that the T/W is unrealistically high, although this is to deal with KSP's time acceleration system rather than the Kerbol system. Your best bet for ion engines would more likely be RSS with percipia (real gravity overhaul mod) added (assuming it can handle time acceleration with an "accelerating" craft, which is pretty much what it has to do with n-body gravity). The big real life problem (that I'm reasonably sure won't be modeled in KSP) is that I've heard that solar panels have issues with the Van Allan belt (by heard, I mean somebody mentioned it in the forum). I've only tracked down an Apollo-era paper about it, but NASA seems to spend a ton of delta-v making sure ion engines (and their solar panels) don't have to deal with the Van Allen belts. Since the delta-v needed to get *anywhere* in the Solar System (especially at ion engine speeds) isn't much more than the delta-v needed to get past the Van Allen belts, this is pretty much the nail in coffin for using ion engines for anything other than sending probes to multiple places in the Solar System.

The point is that you are complaining that Scaled Composites made design decisions differently that your pet ideas, then use an example plane for high speeds that was an absolute disaster anywhere near the speeds you suggest. You are taking a proven design for high altitude flight (White Knight, also the U2 didn't have swept wings) and trying to force it to fit your pet ideas. And bringing up the P-38 as a good example for high speed flight just doesn't work at all. I'd also really like to know how you could possibly suggest that your entire original point wasn't that you thought that the stratolaunch should have swept wings to hit mach .86. From https://airandspace.si.edu/collection-objects/lockheed-p-38j-10-lo-lightning You'd be surprised how soon transonic problems happen. It doesn't matter if the airplane is traveling at transonic speeds or not, once *any* airflow gets there the problems start.

You're the one insisting that not having swept wings slows down the jet powered Stratolaunch too much. Wiki claims that the P-38's problems started at mach .68 (it was a propeller craft, remember). If you've given up high-speed flight, there is absolutely zero reason to sweep the wings. I also suspect that the tail-wings were simply inherited from the original proposal to use actual 747s as the twin fuselages and that the rest of the plane had already been designed for those tails. I'm fairly sure your reasoning is entirely backwards. The advantages of arbitrary launch (although not *quite* as impressive as they sound due to the funky "go well past GSO, adjust attitude, then circularize" that GSO use) is more important than not needing a nozzle that operates at sea level and "climb as far" is so amazingly trivial I laughed when I read it.

That's pretty much what art is (unless directly sold to a buyer). I'm also more than skeptical of the "illuminate on special occasions". It would either have low-lifetime onboard lighting or require laser illumination from Earth (or somebody standing on the Moon with a flashlight), so I expect that is just kickstarter propaganda.

I'd guess it has to do with trying to maintain rigidity or avoiding harmonic vibrations to travel around the loop. I'm not certain how much was understood about the P-38 when it was designed, I know it had issues related to transonic flight that were completely unknown until supersonic flight was more understood. I'd hardly assume that everything about that plane was "better". Of course, this is more a wild guess (I have almost no training (formal or otherwise) in structures and just ksp-level understanding of aerodynamics). I think the main point is that if you want more lift (and higher ceiling), increasing speed increases drag by the square of velocity, while increasing wingspan increases drag linearly. Not only that, but the paired fuselages work to help extend wingspan, as the White Knight and Voyager show. I'm guessing that White Knight simply didn't need that much tail (and extending it wouldn't make sense), and I wouldn't be too surprised if the entire length of the Stratolaunch plane is shorter than the distance between the fuselages.

I'm confused. I think I multiplied by g instead of dividing. I'm also confused by the need to dilute the exhaust gasses when the output appears "close" to the more efficient claims of more modern nuclear thermal rockets. If the dilution is relatively minor, then my SCRAMJET idea is pretty pointless.

That and how long they last while making the stuff.