Terwin

Falcon 9 hits Max Q after roughly 70 seconds, this is also shortly after it passes Mock 1 Wikipedia says the fastest air-breathing aircraft is the SR-71 blackbird that hit 2,193.2mph/mock 2.81 in 1976 The falcon 9 first stage only burns for 162 seconds. For a first stage air-breathing engine to work, it would, at best, replace less than half of the first stage. This would cost the use of an extra set of engines, an extra recovery, and lots of extra development. I just cannot see a sufficient increase in efficiency during the first minute of flight to warrant splitting up a less than 3 minute burn across 2 stages.

Hydrogen leaks. Through anything. While doing so, Hydrogen also make the things it leaks through more brittle. Leaking that hydrogen into a LOX tank seems like a good way to get a big explosion.

I figured that a chunk of the reason to do the 'hammer toss' would be to transfer additional energy from the booster to starship. After release, Super-heavy wants to turn around and slow down, while Starship wants to speed up more, so any sort of momentum transfer should save dV for both. Center of mass is probably still inside SH, due to all of the engines at the base, but Starship should have a majority of the remaining weight, so this little maneuver may transfer a significant amount of inertia from one to the other. Even a few dozen m/s transferred might save tons of fuel, and those would be tons of fuel at stage separation that did not need additional dry-mass.

I think you overestimate the rationality of the average activist or dictator. They may not actually be able to do anything(depending on the organization that uses the nuke), but they will still raise a ruckus.

Relationship dramas are very much a Pathos(emotional reasoning) thing. A lot of the most impressive parts of Rockets are dependent on Logos(logical reasoning), in part because the sizes and scales do not make a lot of emotional sense. (a teaspoon and a 5 gallon bucket are easily recognizable sizes, a 5-kiloton rocket is much more abstract, and for the observers, the explosion took up less of the visual field than your average professional firework mortar, so you need a logical understanding of the scales for it to be appropriately impressive)

As far as I am aware, no one has taken a Launch abort pod version of starship off of the table. My understanding is that Elon would prefer to have a starship so reliable that transferring passengers to and from a Dragon capsule for ferrying people to and from the earth would actually increase the total risk of the end-to-end voyage. Like so much else, this is aspirational until it has been demonstrated as possible. My expectation is that the first several 'manned' starships will launch without crew and get a transfer from a Dragon(or possibly SLS) capsule. (probably for a trip to the moon) I also expect Starship to have 100+ flights and probably 50+ consecutive 'norminal' flights before it ever launches with crew on-board, even a version with a LES pod. I consider both launching and landing a Starship design similar to the current one with crew(on earth) to be aspirational as opposed to expected. And just like other Musk aspirations, they will be great if they can be managed, but that is by no means certain. I will be pleasantly surprised if there is never a need for a starship 'shuttle' configuration with a smaller second stage and built-in LES(similar to Dragon) that is only used for transporting several dozen(or perhaps 1-2 hundred) people to and from orbit where it docks with longer-range starships that will actually transport them to the moon/mars/stations outside of LEO. (replacing the more expensive ticket of using a Dragon capsule for this purpose)

Compared to what? Interstellar space(1/10 particles per cc) is a vacuum compared to the solar wind, the solar wind(5 particles/cc) is a vacuum compared to the surface of the moon, the surface of the moon(10^4-10^5 particles/cc) is a vacuum compared to Mars, and Mars(0.02 kg/m^3) is a vacuum compared to earth, and earth(1.3kg/m^3) is a vacuum compared to Venus, and Venus(65kg/m^3) is a vacuum compared to Jupiter(25,000 mile deep ocean of liquid metallic hydrogen). Can it enter the solar system? Can it land on the moon? Can it land on Mars? Can it land on Earth? etc. If you are trying to write a story, spending all your time coming up with rules about the universe is a backwards way to do it. First you come up with the story, then you identify interesting complications that can be added to the story. Only then are you in a position to do general world-building, and it must be constrained by your story. (and every question you ask would need to include the relevant story-beat details so helpers know the constraints) And frankly, anything that involves startrek-style shuttles is science-fantasy at best.

Only if you want to SSTO from a large body. Demios has an escape velocity of only 20kph, letting you both land and launch with only about 12m/s/s of thrust. This would let a MMU land and liftoff twice before running out of fuel, and any 'real' rocket could probably do a lot more. But for earth? Any realistic rocket using less than 50% of it's wet-mass as propellant to get to orbit is pure fantasy. (the real number is probably above 80%, but I am willing to allow for new technologies like rotating detonation engines getting that number lower, just not *that* much lower)

The placement is random, but once you have surveyed a biome, you can edit the resources remaining in a specific biome in your save file.

To keep things cryogenic you would need larger radiators and a lot more power. Radiators are more efficient the hotter they are, and it takes more power to move heat from lower temps to higher temps. It is not just Styrofoam and a mini-fridge. It also means that any temporary power loss could let your fuel boil off. Also, long-term storage of hydrogen is not really a thing as far as I know, between embrittlement and and just seeping through solid materials, hydrogen just does not like to stay in place. It might be easier to take up water and just use electrolysis(adding a delay before any burns as the fuel is produced). Hypergolics are also much easier to ignite as they are hypergolic, greatly simplifying the engine, and reducing points of failure.

Going by Steam telemetry sure, but if you ever used mods in KSP1 you know that you do not play with mods in the steam directory, so anyone playing with mods or otherwise not using the steam launcher will not be in those statistics as an active user. (and at this point of the dev path, there is a lot of need for mods) I got errors launching through steam, so my 'play-time' is all of 2 minutes back on release day. I 'landed' on the Eve seas before the patch and did a mun-minmus tour after the patch. (my 'landing' was about as stable as the game-ball at a NBA game, but the vessel was still intact...)

If you only need 'gravity' for people, then just use steel plates on the floor and magnets in your boots. Simple, practical, and the energy requirements are low enough that it can be provided by the muscles of the person(mostly for lifting your foot away from the floor) You should even be able to tune the strength of the magnets to minimize or eliminate muscle atrophy in the legs(even if the muscles are likely to re-allocate a fair bit over time). This may even act as 'training wheels' for people not accustomed to microgravity for long duration flights on large vessels(like a starship to mars).

Looking at the roadmap, he might be putting a lot of it into the core KSP2 game. It might be more enlightening to ask if he intends to migrate his LS mod, as it sounds like that is less likely to be integrated into the core. That said, it may be a while before he has the free time to work on mods, as he is probably putting a lot of extra hours towards his day-job. I hear they just released a large product in early access and are working hard on supporting it.

"How many groups do you get if you take away zero at a time from your starting set?" Divide by zero is also something of a bug in math, as anything other than 0/0 is nonsensical. Computers operate on math, so when they try to perform an operation that should produce a nonsensical result, they have a problem because they cannot handle said nonsense. Computers are also not able to calculate infinity, and any attempt to do so will also result in problems due to limited computation/storage space. Division of floating point numbers is also the most difficult and time-consuming operation that computers perform, so optimizing those operations, especially pathological cases, can shorten the cycle time of the processor, allowing for an increase in clock speed. (that MHZ or GHZ number that they list for the CPU or GPU)

Steam says I have 2 minutes of play-time and I last played on Feb 24th. Why? Launching through steam does not work for me, so I run it with a short-cut to KSP2_x64.exe in my games folder. Remember all the advice about not playing from your steam directory because it will mess-up your mod installs? I expect that is also having quite a large impact on the steam statistics, even if there is not much in the way of mods just yet. Old habits die hard I can tell you that I have played KSP 2 a lot more than steam thinks I have, even if I am not playing as much as I will once there is some form of progression. I suspect that the launcher is having problems because of my multiple monitor set-up(3 monitors with two different sizes), but as the KSP 1 launcher did not work for me either, I just shrugged and created my own short-cut a few minutes after downloading the game. While I will likely leave a review once KSP 2 is more feature rich, I am not expecting any of my future play-time to be reflected on steam, especially considering how frequently I used mods in KSP 1. Edit: I got KSP1 from the squad store, so my only 'KSP' activity on steam shows me downloading KSP 2 and abandoning it in less than 5 minutes. Not sure how many hours I played KSP1, but my hours played would be at least 4 digits.

Perhaps the inevitable slips would go over better if they used a NET Date instead? Presumably everyone here would be familiar with the implications of that term as it is used for every future launch date, and those are frequently delayed with few or no recriminations...

Isn't that sort of the reason they set out the major features and the order in which they plan to implement them? 'These features are not yet present, but we plan to add them, if you deem one or more of them to be required before you want to buy the game, then just wait and buy it when those features have been added, and continue to enjoy KSP1 until then.' It just turns out that there are some less major mile-stones that are also needed for some players, but no one was aware of them in a time-frame to do anything about it.

Ah, that explains why I have not seen this issue, I was not able to launch using the launcher, I had to go to the KSP2 directory and run KSP2_x64.exe directly to get it to start.

I'm excited for stock interstellar colonies that can launch their own ships.

Every human in space comes equipped with a pair of bellows attached to an adjustable nozzle and a pair of paddles. So if needs be you could 'swim' or 'blow' your way towards a hand-hold. Not that it would be fast, but it would work.

The down-side of needing a combustion chamber that can handle properly mixing and expelling both combinations seems highly problematic. Even with a normal engine, you have space issues putting all the injectors you want where you want them, so having two sets would be very difficult(not to mention the space for piping), then you need the throat to be properly tuned to both sets of combustion, which seems unlikely to be an easy thing to manage, as well as putting substantial constraints on the relative fuel flow between the two reaction types(volume, temperature and pressure capabilities of the combustion chamber and throat will not change between fuels after all, and this may reduce isp to the point of making it worthless for many/most combinations)

Counting from the formation of the earth to when the sun expands to engulf the current earth orbit, we are less than half way along. To ensure that no life will evolve after a sterilizing event before the end of this epoch, would likely require the earth no longer be a planet in the goldilocks zone.(or any other 'zone' that turns out it can support the development of life) As such, hopefully we will have enough time to become multi-planetary before whatever comes and either turns the earth into an asteroid field or changes the orbit enough that it an never again sustain life.

If you hook the loose bit over the end, it should pull taught and thus extend the hook-part past the end of the tape, if you butt it up against an edge, it should push in so that the measured end is still accurate on the tape measure. Personally, I usually start measuring at the 6 or 12 inch point on the tape and subtract that from the end point when feasible, because the loose bit also bothers me...

As far as I can tell, the StarWars universe has anti-gravity tech that is pretty ubiquitous and used in everything from wheel-barrows to starships, with no real energy requirements. I do not believe that any StarWars vessels actually get up to orbital velocities, and just sit there on anti-grav instead. (this is why they can 'fall out of orbit' if they get too damaged, and also why a bomber can drop bombs on them from above) Hyperspace probably involves some sort of Albercurrie drive using the same tech. The 'engines' at the back are more akin to fairy-dust vents than actual engines, and may only be relevant for hyperspace.( perhaps venting something that helps prepare the area for hyperspace?) If you give me that magical anti-grav tech, I could get you a family-car sized vehicle that can SSTO to the moon and back, possibly using a compressed-gas thruster to ease the transition between the earth-dominated and moon-dominated gravitational domains.

If you have arbitrary amounts of power available, then this should be indistinguishable from an ion thruster(assuming that your magnetic thruster works at all). I do not think that an ion thruster requires a particularly large exhaust area per unit of thrust, just large amounts of power(a sizeable chunk of which is used for stripping electrons off of the reaction mass to turn it into ions which you can push with electromagnetism) As current ion engines have ISPs in the 2000-5000s range, that should be adequate for SSTO if you have arbitrary amounts of energy available without needing arbitrary amounts of weight to generate it. With 5K isp and >1g thrust, you should be able to get to earth orbit with only a ~20% fuel fraction(I think) So even if ~30% of your vessel is dry-weight(power/structure/engines), you could get 100t of cargo to orbit with a ~200t launch weight using a 5000s isp engine with sufficient thrust. The current problem with high-isp engines are the thrust-to-power ratio where you need at minimum of ~50kw per newton of thrust for a 100% efficient 10,000s isp engine, or ~25kw per newton of thrust for a 5000s isp engine. This means ~50w per gram at 10,000s or ~25w per gram at 5,000s to accelerate at 1m/s/s, so you would need at least 10 times that for launch. This means 500kw/s or 250 kw/s for each kg of launch weight. The SSTO above would require >50gw/s from a mass of less than 600kg(which also includes the engines and structure) for long enough to get to orbit(for more than 8 minutes), requiring an energy density of more than 40 giga-joules/kg. This is roughly 300 times the fuel density of hydrogen(not counting the weight of oxygen, I think) or only about 1/2000th the energy density of uranium. Clearly this would need a nuclear reaction to produce the power, but would require a 50gw nuclear plant at a mass of perhaps half a ton.(not something we can manage today, and would need massive heat-ejection capability)