monophonic

You think many injectors on single chamber is silly? At one point von Braun's team planned to use six chambers on one nozzle for the A10! Presumably each chamber with a silly number of injectors.

I'll also throw in the AMaRV or Advanced Maneuverable Re-entry Vehicle. It was a nuclear warhead the USAF developed in the seventies and flight tested at the turn of the eighties but never fielded. It used flaps not entirely unlike KSP airbrakes to pull hairpin turns at hypersonic speeds.

1. In hydrogen bombs the heat and pressure necessary to start fusion is reached with a small fission device. So no. There is also the intermediate level of boosted fission device, where a small amount of fusionable material injected into the fission core provides a significant boost to the energy output. 2. Depends on the exact technology level, namely how difficult it is to reconfigure the guidance system, but not very much. You may lose some range or be limited to longer flight times as the airframe may not be strong enough to fly the optimal trajectory. Specifically for the M-V rocket, though, it has been suspected to be easily weaponized. 3. @DDE gave a much better answer above than I ever could.

On the other hand if the rover broke down before you dropped the carousel you would lose all the samples. Just goes to show how unrealistic the entire "sample now, collect later" strategy is, I guess.

The civilian GPS signal used to be artificially noisy to limit the accuracy. This was called "selective availability." They have turned it off now because augmentation methods and other GNSS systems have made it ineffective plus a lot of civil and merchant activities have become dependent on accurate location. To my knowledge the capability still exist even in the newest satellites. But for example my cell phone's navigation chip picks up (at least) GPS, GLONASS, Galileo and Beidou satellites. The app I check this with lists a couple more systems and has a category for unknown satellites too. So fiddling with just your own system's output may turn out to be ineffective as a drone protection. For the curious this also is (one way) how the russian GPS spoofing that's been in the news every once in a while works. They drown out the satellites' transmission with their own that causes the calculated position to drift off the real position. Careful calculation should allow them to control how much and where the drift is at least in a limited target area. Less predictable effects will happen outside the target area, of course. Countermeasures include encrypted transmissions that the malicious party cannot create (GPS at least has these), directional antennas that reject the spoofing signal coming from low elevation and listening to a lot of satellites and rejecting the outliers whose transmission suggest a position far from the others.

Try thrust vectoring when your nozzle is affixed to the skin of the space craft. Well, vanes or propellant injection would still work, but there must be a good reason why most TVC capable motors go for the moving nozzle system.

Perhaps it could if done by selective breeding only as that process dates back to prehistoric times. Direct genetic manipulation certainly wouldn't be primitive at least by today's standards. What would be considered primitive at the time there are colonies on other planets that would consider themselves to be primitive is up to anyone's imagination.

Is it really necessary for the biological part to travel to space? I say use something like coral animals or maybe insects that have been bred and/or genetically manipulated to grow into specific shapes and make their exoskeletons out of something suitable for the purpose. So take one shed starshipbeetle shell and install a few raptorcoral husks at the bottom. Okay, for the control computer you might need something living. Dogs are known to learn many tricks so pick a breed for a starting point. Make sure there is a well protected place in the ship for the - quite literally - ship's brain to sit in. Then just go play fetch with asteroids or something!

Maintenance costs mostly, I should think, especially with podded propulsors. The complex angle gearings required for mechanical ones can be quite hard to get to for servicing. I have also seen lesser space requirements mentioned, as there is no need for big shafts running from the engines to the gearboxes and propellers. Oh, and electric transmission completely decouples number of screws from the number of engines. Power splitting and combining gearboxes are very specialized things and can be hard to maintain or even get right in the first place. (See Freedom-class combining gearbox issues.) The technology has advanced by several magnitudes since the eighties, don't even mention the sixties experimental SSNs let alone the battleship era systems. As mentioned complete electronic propulsion systems from engine to propeller/wheel are now commercially available off the self and with both wide and long service history. Very high power semiconductors appear to have been the key to efficient and reliable electric propulsion. In the submarine context there is also another consideration. Without mechanical links between the turbine and the propulsor the designers gain extra freedom in designing the frequency characteristics of each end. Not to mention reduced vibrating mass means less radiated noise overall, and the space gains leave room for additional quieting measures. Very very very important for an SSBN.

The wonderful people of Project Rho have put a frighteningly large amount of though into exactly this. In short, mortgages, part payments and group buys would not be only possible, but downright required for private people to buy even the cheapest of starships. The other side of the coin is that you can use those to drive your story/plot to specific directions i.e. a trader failing to generate enough profit to pay off the debt may turn into piracy. Anyway, here's the link to the relevant page: http://www.projectrho.com/public_html/rocket/starshipowner.php Have fun!

Newer US submarines have their reactor cores built to last for the entire lifetime of the submarine. That will be 30 to 50 years at current estimates with just the original fuel load. Unless the NTR is the only power source on your spaceship it can be run for a considerably lesser fraction of the ship's operational life than a submarine's, which (abnormal situations aside) is only shut down while pierside and on shore power. Therefore I would expect that other systems on the space ship would start to expire long before the reactor core dies. Of course such a long life reactor cores require fuel refined to a very high purity. While I have no knowledge I suspect it could be considered "bomb-grade" even. This constrasts with the French who are determined to use the same civilian grade fuel their nuclear power plants burn. Thus they have to refuel their submarines (and the only non-US nuclear powered aircraft carrier in the world) every ten years or less. So if politics restrict the purity of fuel used, refueling the NTR may become an issue to be solved.

I don't think that would be a big problem, not technically at least. After all, Soyuz does exactly that and it has worked more than once in a real emergency. But it would probably require a completely new fairing and payload adapter, I imagine. Doubtful if the existing ones could be easily adapted to withstand such stresses as they would experience in an abort situation. There's a hole right there to sink money into. Any extra mass would come out of the cargo too, but that one is true of any LES system.

I'd bet that if anything, the fuselages would have to be more rigid if they were connected at the tail. As is they are each free to flail about as they like without worrying about the other one. If they were connected any differential forces on them would concentrate as all sorts of stresses in silly crucial points in the structure. I think that may also be a major driver behind the separation of the hulls, to minimize any turbulence caused by one interacting with the other. I think what NG wants in Stratolaunch is the plane. As the last TriStar in operation Orbital's StarGazer is no less bespoke and closing in on it's 50th birthday must be getting expensive to keep flying. Whether building it was financially reasonable can be argued, but as somebody else has already paid for it NG can just as well reap the benefits from having a plane specifically designed for the job. So I expect Stratolaunch to merge into their Space Systems sector in not so distant future.

It's not just stealth - it is also a decoy free of charge! But wait, there's more! Drop the outlet inside the enemy ship and now it is a weapon! Can you believe it? Call in the next 15 minutes and receive two for the price of one! Sorry... I'll show myself out.

Some legal issues might be side stepped if you mix your explosive components in the chamber itself just before the detonation. Now tell me how much stoichiometric methalox can you pump into a chamber before it spontaneously ignites? Presumably the methane and oxygen should come from separate inlets but we would also want them to evenly mix before setting them off so probably not at the opposite sides of the chamber.

Thanks @kerbiloid and @K^2 for putting that thing to rest. We have the claim that the plate was identifiably intact in that high speed film frame. If true that would point towards the relatively flat end of your scale. Curiously enough I seem to have a memory of seeing that film frame somewhere online once. Yet I cannot find it or any mention of other people seeing it anywhere. I must have dreamed it up or else it must have been an "artists impression" (i.e. a fake).

This leads in nicely to a though I have not seen discussed anywhere. Note I do not possess the math cells to arrive at a conclusion myself, so I am merely throwing this out here for anyone with the skill and interest to do so. So the though goes, despite the concrete collimator between the device and the steel cap, the first thing from the explosion that reached the cap would have been the x-rays? So how strong would those x-rays have been? Could they have evaporated significant thickness of the plate in place? And how much force would that ablated steel cloud, expanding down the shaft, put on the steel cap as per Newton's third? How fast could it have pushed the now lighter remainder of the cap? Could that and the vaporized collimator cloud have combined for even more force? Now I feel like a 5 year old kid asking questions far too fast for his parents to answer any of them...

Except you can't. Not one that is useful anyway. You see, the thing about a space elevator is that you want the upper station to be at the geostationary orbit. That way your space ships can come and go docking to and from your elevator as they please. At any other altitude your ships need to furiously burn rockets right to the moment the docking clamps connect just to match the motion of your elevator station. Strong rocket blast is something you definitely do not want happening right next to your precious space elevator. Problem with the Moon is that it is tidally locked with the Earth. As it rotates so slowly, once around every 28 days and a bit, the theoretical selenosynchronous orbit is actually way outside the Moon's Hill radius. In other words, you won't be orbiting the Moon at that distance, you will be orbiting the Earth or the Sun. Now you might think it could help you get started on reaching actual orbit. But you won't get any useful amount of velocity from the increased radius due to the very slow rotation, the difference in gravity compared to the surface is minimal, and there isn't any atmosphere to get above of. You could build a much bigger linear accelerator right on the surface and use less resources on it than building a massive tower to put your launch system higher. Well there is the Lagrange point between the Earth and the Moon. That would be a nice spot to drop off cargo, right? Just a little push and the gravity from Earth should bring the pod down essentially for free? True, but that spot is over 60000 kilometers from the Moon. Even at 1/6th the gravity I don't think our current materials can handle that, even when not considering the tidal forces on a structure that long. So there isn't really any point in building a space elevator on the Moon. It wouldn't bring you any advantage over just putting your launch pad on the highest spot of the Moon at the Selenean summit. Now Mars, on the other hand... maybe somebody else can check the numbers for that one?

Although in reality many a SPAAG/SPAD do carry some sort of radar on them. You don't have to turn your flashlight on just because you have it, but when the bad guys shoot out the streetlights (surveillance radars) you are blind without one (to keep with the analogy; LLTV and IR imagers do exist and are used on SPADs too for night operations). Many SPADs (e.g. ZSU-23-4, Gepard, Roland, Tunguska) specifically were also meant to protect armored forces on attack, so they had to move at high speeds over rough terrain (to keep up with the attacking MBTs and IFVs) while being capable of engaging rapidly appearing targets at a moments notice. So they could not count on communications to and coverage of higher eschelon surveillance radars to be there for them. They fell out of fashion in the west after the Cold War ended but Russia has kept building on the Soviet legacy systems after the 90s slump. Even they seem to have put more emphasis on lighter systems like the truck mounted Pantsir over tracked and armoured types like Tunguska, but those do still have radars. The export and news coverage of Pantsirs in Syria and elsewhere may have made that shift seem stronger than it really is though. Their effectiveness against the much improved missiles of today can be legitimately challenged, and that is part of what is driving current developments towards lasers and other direct energy weapons in air defence. (Drone swarms being the other big driver but that is another discussion.) All in all the balance of weapon versus counter-weapon keeps swinging from side to side, and the only constant is that they all keep getting more and more expensive.

Well, I followed the references from the wikipedia page. That value is measured on rats.

Indeed, I was just laughing at all the stupid jokes we missed because they did not announce launching Starliner on April Fools' But that's just my sense of humour that I picked from the trash can in the QA office.

How much for they only needed to delay for 7 days, looked at the new date and decided to wait one extra day?

I guess without any instruments on the sky-crane it would be rather moot, and any instruments (and comms you need to get the data from them to Earth!) you might add would be extra mass you would have to give up on the rover instead. You don't need to reserve as much fuel for a ballistic hop away from the rover than you would need for a smooth landing either. So I think any such consideration probably quickly converges on "better value to put every ounce we can on the rover."

Awesome! And genuinely scary. But in a good way, 1990 scary, not 2020 scary. Thank you!

Hey, the goal is to break off a piece and collect it for processing. There is a still better technology for doing exactly that, one that doesn't involve imparting any impulse on the mining vessel nor shooting the broken off pieces in unpredictable directions at inconvenient velocities. Circular saws. Just cut off the piece you want, you can even have it attached to whatever means you use to move it into the refinery systems ahead of time. No need to waste dV chasing after runaway bits. Except if your asteroid is a loose pile of rubble like Bennu, shovels.