wumpus

Sanitize telephones. Produce marketing goals. Hand inspect circuit boards when ML imaging can already to it better. This predates AI: https://www.goodreads.com/book/show/34466958-repurposed bovine waste-jobs

I'd assume that the logic for hitting the thing would be to break it into smaller pieces which would be more likely to burn up in rentry (although the engine is likely to impact in any event, this way it could bring less mass with it). I'm guessing time is running out to hit it in perigee (so all the pieces will be in an equally unstable orbit) as the more atmosphere it goes through the more erratic the movement. Perhaps they could hit it as it gets sufficiently deep into the atmosphere that all the parts will come down quickly.

When I was a boy scout we'd do things like visit military bases in January because we were to wimpy to go camping. One of the bases was Dover Air Force base (it was the during the cold war, so any bodies brought back were likely training accidents and low profile to keep the guys enlisting). At the time, a C-5 pilot flying between Dover (an hour from the beach) to Dusseldorf, Germany had to have the cushiest job in the military. And then leaves the service with all sorts of hours in wide body jets set for civilian life. Which is probably why they were more than happy to put scouts up for the weekend in Dover AFB.

The x-43 based orbital launch platform exists only on Powerpoint slides, or perhaps just as a "proposal for further funding", but the X-43b/c test drones did exist (and possibly still exist at the bottom of the Pacific). It isn't clear if you would want to make such a beast two stage (like Spacex does) and recover both. For the TSTO, I'd suspect you'd have to make your air breathing engine accept LOX oxidizer to get it out of the atmosphere to stage. For SSTO, you'd be carrying an awfully complex engine/set of engines to handle the delta-v from subsonic to > 1000m/s. The x-43 proved that it can maintain > mach 10, although that was even more a proof of concept than the mach 6 flight, but that might be enough to pave the way to SSTO (although I still think that Spacex's reusable TSTO is obsoleting most of the need for SSTO on Earth). Unfortunately the x-43 program has moved from NASA to USAF, and is now classified. No idea if we'll ever see it again.

I think that became obvious about a decade ago when spacex dropped the falcon5. To those who know little of space, it sounds like a great idea (especially if all they know is how much fuel a rocket burns to get to 10km). Once you understand that your entire benefit is in orbital inclination and nozzle optimization (I suspect "vacuum" nozzles work fine at 10km) it gets a little iffy. Then when you look at the issues of topping off cryogenic propellants* and hard limits to expand your rocket it gets worse. Once you start working out the cost/benefits, you start to realize why the US space program started in Cape Canaveral at sea level and not Leadville, CO (two miles up) or Mauna Kea, Hi (better inclination, probably further from the Earth's core). It isn't much of an advantage. * the Pegasus family of rockets are all solid.

The point is that Congress will still have the last word. If they want to hand it to BO, they could always include a maximum height requirement in the funding or something else Spacex can't achieve. I doubt they like to do this on a regular basis considering just how many contracts are out there (I think the Pentagon decided who would build each generation of fighter jets (a far more massive contract), and Congress didn't override them. But almost all the criteria were political). I think Congressional overrides are more typical in changing how much they will buy/pay for. And often they insist on paying more than the original customer wants (typically big defense contracts, but the SLS is a great example. I can't imagine NASA like seeing all their budget go to that). But they'll still need an act of Congress even with a winning lawsuit.

Presumably the only way to convince NASA would be to cut the price down to what Congress authorized. Doing an end-run around NASA and convincing Congress might work better.

First, what you want is light elements. Hydrogen is ideal, water is ok. Note that using water means your Isp won't be any better than hydrolox. Lunar regolith is inferior to water, but I can't tell how much (and perhaps you can at least process it down with your reactor before launch, so at least you have just oxygen). If you can get enough carbon dioxide from Mars, maybe you can simply feed graphite into your reactor. One thing I can't stress enough is that this makes SSTO off Earth-sized planets next to impossible (unless you are cracking water or hydrocarbons for the hydrogen). Getting high thrust out of nuclear thermal rockets would require tremendous cooling, and you'd have to try to stop the reaction immediately after liftoff (and hope that by the time you stop needing propellant, your reactors are cool enough for closed loop cooling). Trying to do this while lifting a nuclear reactor and having an Isp less than hydrolox (efficient hydrolox is fuel-rich) just isn't going to happen when you need a delta-v of over 9000 (m/s).

I'm not sure that either lithium ion nor nickle metal hydride are cheaper than lead acid on a kWhr basis. But as far as vehicles go, they seem to only work on fishing boats and golf carts, not cars for highways. And the golf cart use might only be holding on as they make excellent ballast (for all the crazy hills golfers will drive/park them on). Even in ICE cars, a lithium ion starter battery is a pretty exotic item (although LiFePO4 is what you want if you absolutely refuse to even have a hybrid ICE engine, or want to "add lightness" to a legacy car). Lithium ion in "power walls" is largely a means of recycling batteries no longer fit for cars (like lead acid). Presumably once there are enough lithium ion batteries in easily harvestable containers (not cell phones) then lead acid batteries won't be economically viable at all.

Hard to beat the classic: https://en.wikipedia.org/wiki/The_Cold_Equations_(The_Twilight_Zone) But probably beat the one I first thought of: https://en.wikipedia.org/wiki/Stowaway_to_the_Moon

I don't think Star Trek has tried since the early movies, and clearly gave up early in Next Generation when it worked better as a soap opera than as science fiction. They are just stuck with a lot of "pretending to be realistic" inertia and only make a nod to realism in getting close to the right words in the technobabble.

As far as I know, you could build* 30hp electric motors (granted, they were AC ones, I'm assuming you could do the same with DC) most of this time. This is roughly the power in the electric motor of a Prius. The infallible wiki lists a model-T at 20hp (early VW beetles produced a little more), a Chevy Bell Air (pre-1955 I-6) at 95hp, and later (i.e. the classic "'57 chevy" and similar models) V8 small block at 162hp (base). The Prius has a "combined hp" of 121, presumably meaning roughly 90hp in the ICE. My guess is that a (modern style) hybrid would make sense for post-war production (depression-era production of high power wouldn't make sense, nor would building a hybrid out of a 20hp engine. The tech was there, the market was not). One big problem is that you would have to slowly charge the lead acid batteries or lose half your efficiency, and simply using them hard (the whole point of a hybrid) would also lose half your battery efficiency. They would probably work well (in the US) for light cars made in the 1970s and 1980s, with <100hp engines (like the prius). This should keep the ICE in the "BSHP island**" and still have enough total hp to move the car. The combination could presumably work for the early Bell Air, but trying to convince 1950s America to stick with it in when "they could have had a V-8" would be difficult. My understanding was that in equal dollars, 1950s gasoline was at least as expensive as in the typical OPEC era, so it might have been possible to sell a car with great mileage, but even then it would be a challenge. Of course, the first car Ferdinand Porsche made was a serial hybrid: you have an ICE to run a generator, and an electric motor to move the wheels. Solves the problem of having a transmission, but once remotely good transmissions were available this system was scraped (at least for cars). A hybrid with large batteries might have made sense in a depression-era car (running the ICE exclusively in the "BSHP island", but would require a huge battery to avoid the losses associated with fast charges or discharges. Also the whole system just sounds to complex for that era, especially in cost. * obviously you "could build" a more powerful motor. But you'd need a smaller (geared lower) motor to start it. The electric car motor might even need a lower first gear than the ICE to get started, but then could presumably switch to a higher second gear sooner. ** "BSHP island": an ICE is most efficient at about half throttle*** at peak torque, so at roughly between 1/3 to 1/2 total power. Outside of that range, things fall rapidly. And regardless of how much horsepower a car needs to "get out of its own way", producing more than 30hp for even relatively short periods can lead to excessive speeds. This is why the Prius (which can typically drive in that island) gets such good gas mileage, and why lightweight, low power cars (last seen in the US in the 1980s) could achieve similar numbers. *** the 'half throttle' may well be a function of engine compression and the need for modern engines to go fuel rich at higher power levels to avoid knock. I suspect that the carbureted engines of the time had max efficiency with wide open throttle . I'm not that familiar with the specifics of engine design and even less familiar with this class of retro tech.

Except that the most effective cars of that era (at least the winners of retro hill climbs) weren't electric, but steam. The Stanley Steamer was extremely effective for its time, although it might have had a long "warm up" time (see modern "plaid" electric requirements). I suspect that ideal hybrid cars should be using a turbine, although a gas instead of steam tubine. [note, I still don't know why 30hp turbines are inefficient. I'm an electrical type, and only dealt with thermo in "physics for engineers", not a separate class] Don't forget that the "petrol heresy" was largely using a waste product (that dratted infrastructure again) as a fuel compared to expensive electricity. Also I'm not sure just how many places were fully electrified 1900-1925: electricity might be assumed to come to homes (and parking lots) *now*, but not necessarily back then. I'll have to revisit Verne. I haven't read anything of his since ~1980 (when I was fairly young) and I understand that better translations are available. I suspect that not only were the translations I read pre-1965, but the books themselves (from a library) were as well...

I'm not sure of the point. While lead-acid batteries were invented in the mid-19th century and presumably available in the early 20th (and needed for car starters toward the end of the period examined), I fail to see how they would be better for cars 1900-1925 (and especially past 1925). It isn't so much a missed opportunity as tech simply not being there. On the one hand, you have the king of the 20th century, the ICE. It suffers from terrible emissions, tends to only be efficient at full power and uses a throttle to strangle the air (O2 and gasoline) supply of the engine to reduce power. This makes sure the thing is badly inefficient, and the efficiency gets worse as the car gets more powerful (typically meaning >100hp in modern US [bloated] cars). On the other hand in electric cars you have lead acid batteries running directly to brushed DC motors. I'd be shocked silly if they were using vacuum tubes to create a switching power supply mechanism. Regulation would presumably involve a rheostat, and be unlikely to beat the efficiency of the throttled ICE. I'm pretty sure effective chargers existed, but I doubt they would be so concerned with efficiency (you need a constant voltage, then just use a trickle charge). It doesn't look at all like a modern electric car, and such things weren't really possible until at least roughly the time of the EV-1 (1990s). I remember seeing a 1970s electric car (probably some sort of "green" exhibit). I think it resembled a trabant in shape, size and power. But probably worse in all respects. And for most of the twentieth century, there would be little point of advocating "green power", with the exception of the horror of southern Californian air (which was still scary when I was there in 1995). More likely, your best arguments for electric power would center around countries with plenty of resources to make electricity (*) but issues dealing with countries that had plenty of gasoline producing crude oil. You need a lot of technologies that weren't available in 1925 to build an electric car, and Lithium-ion batteries are just the start. The next critical item is some sort of current switcher needed to produce electric motors with enough torque to move themselves (let alone the car) and also function at high rpm (for something resembling high speed driving). Not to mention you'll need similar switchers simply to quickly/efficiently charge the battery. I'm guessing you could build an electric motor that would match a 1925 ICE with just those, but getting much more might require rare-earth magnets. I don't think they were a thing (i.e. mass produced) until at least the 1990s. (*) I'm convinced that "too cheap to meter" was the reason that nuclear power plants are so expensive to make. All the regulation and standard practices were set in stone when electricity was a regulated public utility and thus effectively "cost plus". The power companies would happily agree to any regulation that [slowly, or better yet in the future] increased the cost of power generation as they could simply jack up the prices and thus increase the profits (the "plus" in cost plus). To summarize, when it is steam time, you get steam engines. You don't get electric cars in 1925. The infrastructure just won't support it. You might as well ask "where is my hydrogen car"? The infrastructure simply won't support it.

I'm curious. Can you come up with *any* cases of stockholders rejecting a CEO's attempt to either line his pockets or even spend lots of company money for his own ego's sake? For a company that was otherwise making money and not as an excuse to fire an underperforming CEO? A high profile CEO simply isn't questioned on Wall Street (while making money). Elon might get a lot of flack for much of his questionable publicity, but he never gets any from Tesla shareholders (Spacex is private, he doesn't really have to answer to anyone).

The Turtle Moves. And also provides gravity. The Turtle's physiology is barely touched on. And how the elephants that stand on him survive while motionlessly supporting the disc is never discussed. Don't forget that the speed of light across the Disc is particularly strange (slow). But since it is going through an atmosphere it is at least non-impossible. Don't ask how any living creature breathes such an atmosphere. It's worse than that. As far as the Elves are concerned, the world is still flat. Legolas can look for hundreds (maybe less, but far too many) leagues across a featureless flat plain of Rohan and see features that would dip below the horizon for mortals. No idea if Chistopher Tolkien and Guy Gavriel Kay retconned that in some way to match "the straight road" mentioned in your link. J. R. R. Tolkien was a medievalist at heart and unlikely to be terribly concerned with scientific accuracy, even for things such as the Earth being round. When your idea of 'that silly modern literature that all went wrong' [not meant to be a specific JRRT quote, just compared to people griping about modern tastes] starts with *Chaucer*, you're quite the medievalist. [edit] I had to mention in a youtube comment (you are all free to read it back at me, a la xkcd) about JRRT using the modern archery target colors to describe the accuracy of a statement. But medieval archery targets looked nothing like the sort. [/edit] Wasn't that the plot of an entire year of TOS trek? Kirk: "don't Vulcans have the ability to [magically fix the problem] while floating upside down? Spock: "yes, but it requires great concentration" afterwards Spock: "maybe it wasn't that hard after all." Somehow TOS is as close to literary sci-fi as pop culture gets. Which isn't that close.

Wouldn't you want to change Artemis II to *anything* but a dumb flyby mission? Simply to avoid the embarrasment of burning multiple billions of dollars on SLS to do a mission that Falcon Heavy can do without modification (other than whatever human rating FH would take).

You could adjust the spring profile to get a smoother acceleration profile, but expect it to always want to revert to closer to a sawtooth. Don't forget that on an Orion, some of the efficiency (energy to momentum conversion) scales up as the pusher plate mass increases. Orion can have a reasonably constant acceleration, but I'm sure you'd notice the difference. Might wind up being similar to being at sea (and get more and more stable as larger and larger Orions are built).

"Uncertainty over propulsion component suppliers". Is this implying that they may have to use some sort of hydrolox (almost certainly RL10, especially if LM completes their purchase of Aeodyne) instead of pressure-fed hypergolics, as typical for landers? I can't imagine that buying pressure fed hypergolics would be an issue, although internal politics with the Lockheed conglomerate may matter more than physics. "Lack of awareness of schedule risk". Yes, Elon time has officially infected the rest of "new space".

I'm wondering why kerosene was preferred over methane at the start of the space race. I'd guess that the pressure vessels were too heavy, and that cooling two tanks wasn't worth it (presumably to lower the pressure). You have to refine kerosene into RP-1, and the volume is so low that I'm sure it is a relatively expensive thing to do. After that, existing designs made RP-1 the preferred fuel until spacex decided that even RP-1 had too much coking, and that hydrolox wasn't an option. Back to the original question, propellant costs will presumably vary locally depending on how hard it is to maintain supply. And expect to buy it by the kg, as the volume can vary over temperature (spacex makes a big deal out of this). A fairly busy gas station can require multiple trucks filling it up daily (this makes hydrogen cars sound even more like a pipe dream than without said tidbit), and you'd have to ask yourself how are the propellents brought to the depot. Ion or other electric thrusters (using either argon or hydrogen) should be the cheapest means to high delta-v depots, while other places might have "moon rock" based propellents (I've heard you can make stuff with a relatively bad Isp, but the location might make it worth it), Mars made propellants (metholox), and elsewhere. The classic "skim a gas giant" trope is likely way too far in a gravity well to be useful, but some of these others might work. So the real question comes down to competition and price fixing. Assuming one "celestial body" = "one government" (a classic SF trope), expect that the price of Earth-based fuels (moved by ions or similar), Mars based fuels, and Lunar based fuels are all roughly based on what a another planet (or moon) could supply to said location. The local product either slightly undercuts this, or perhaps happily goes over it assuming a price war would be too costly to maintain .

NASA was somewhat supportive (I'm sure they preferred micromanaging all the details), Congress was responsible for the funding issues.

Still works with Tesla, and Elon time doesn't match calendar time. But there's no point in criticizing Spacex for Elon time when it is vastly more accurate than Boeing, NASA or Roscosmos time. Does Rocket Lab meet its published schedules? I'm not sure Elon makes any predictions about self-driving cars anymore. He might be slightly more careful about PR now.

If Spacex can get Starship to the Moon, what in the world is SLS going to be doing? Of course it has two more years of pork, but I suspect a side effect of Congress choosing Starship (by only paying enough for the Starship option) is that any post-Shelby plans won't require the SLS at all.

I was under the impression that using fuel to cool the nozzles was relatively common. The shuttle certainly used it, and any expander cycle (RL10 and later developments) engines have to use it. So they have been in use for quite some time. RL10 dates from 1962. Spacex obviously prefers it as they simply refuse to use ablative systems as it prevents reuse. Presumably anyone else interested in reuse will try to to avoid ablative systems as well. No idea how common ablative systems are, but I suspect that all early rockets used a combination of air-cooling and ablative systems. I strongly doubt that radiating away heat will work for anything with significant thrust. My guess is that anything that looks this way is being held to a stable temperature by the exhaust gasses, and can survive that temperature (typically in model rocketry and other amature levels). Leave radiant cooling for ions and other electric thrusters.

Only mean if you make them in RO. Between KSP's low delta-v requirements (i.e. air breathing SSTOs will work) and general extremely heavy fuel tanks (to make up for the challenge), they might even make sense. I hope he didn't get any of these ideas from KSP (presumably a short stint. I'd expect more rocket science from a long term player). Other things I noticed: "Copyright 2018-2030 IO Aircraft | Drew Blair". So while it might not be "20-30 years into the future", expect at least 10. And one guy has been using CAD for 2 years (presumably got a ton done during the pandemic) without learning the rocket science of a KSP player. I'm particularly amused by the use of an aerospike in the air-breathing SSTO design. So you want an engine that is wildly less efficient than your air-breathers in the atmosphere (and doesn't explain why you are using it) and also invariably less efficient than a bog-standard vacuum nozzle in vacuum. But since these designs are all about being buzzword-compliant, I'm not surprised.