wumpus

dBells are logarithmic. Expect every chart you see about radio frequency to be done in log format. On the other hand, the signals should decay quadratically (the inverse square and all that), so I'd expect the chart to work better if you scale by the square of distance. (Oddly enough, when somebody nearly explicitly asked for a log chart and I explained how neatly it fit, I was corrected that the *standard* use was quadratic: https://forum.kerbalspaceprogram.com/index.php?/topic/165778-useful-metric-for-high-relativistic-velocities/&tab=comments#comment-3178867 )

If you check the specs, it hardly has any advantages over using 5 J-2s like used on Saturn V. Work on the M1 was canceled in 1966, same year as the J-2 flew and Gemini ended (and pretty much was the end of the "direct flight" option). While there was some ideas about making it a first stage, the shear size of the hydrogen tanks must have been an issue (would such a thing even fit in the VAB?) and getting a reasonable sea level thrust and Isp would have been difficult. Even then, first stage Isp really isn't all that important: if you take off at TWR of 1:1.2 your gravity losses are going to outweigh all other losses so much to make the whole point moot (not to mention some 500,000 tons of upper stages adding to your "dry weight"). I suspect you would want this for a "direct flight" to the Moon. No idea if it was ever designed to be restartable (J-2 was), but you would likely need that for a trip to Mars (you might get away with it on a heavy flight to lunar orbit). Clear mission goals (specifications in most projects) and real deadlines do wonders for engineering projects. They may have produced and abundance of magic, but when it came down to choosing which parts to use for the final design they stuck with things that were known to work (or at least most likely to work for the "insert magic here" parts). Compare this to SLS which is the type of program much more likely to pursue large engines for sake of thrust but is unlikely to produce anything besides pretty museum pieces. - obligatory "Favorite Rocket Engine": Nobody has said a word about Orion [Freeman Dyson's baby, not the current disaster]? Count me in as an unrepentant Orion fanboy. "Orion Shall Rise".

As far as I know, there really aren't many good explanations on how life really formed. Only that if it formed on Earth it did so as fast as possible (and has appeared to do so even as our ability to find fossils increased. I don't think there has been a gap between "earliest possible time to find fossils" and "earliest fossils found" with any statistical significance in decades). This seems rather strong evidence that Earth was seeded from elsewhere, but the lack of [fossil] life on Mars (and anywhere else tested, but we've barely glanced at anywhere but Mars) makes it look less strong.

The most common way of getting rich is via inheritance. So that really isn't a problem (although it obviously reduces who can go even more). Musk does point out that increasing the number of people given the choice to go to Mars is key to large Mars expeditions.

There is also the issue that you can expect any planets to be tidally locked to its sun. The only way to get a magnetosphere is if said tidal lock is somewhat faster than 1:1 (like Mercury's 3:2 resonance).

In the headquarters, there is a strategy option (or was somewhere between 1.1 and 1.2, I can't check it now) to increase rewards from "milestones" and decrease rewards from contracts. It has some extremely stiff reputation requirements (and it isn't all that clear how to check your absolute reputation) as well as the inevitable funds cost. As it cuts contract rewards at least in half, I'd think twice before trying it (or at least be ready to lower game "difficulty" (it really only changes "grindiness')). Unfortunately, the wiki hasn't been listed as updated since 0.90 and this is not listed among the strategies. https://wiki.kerbalspaceprogram.com/wiki/Campaigns This is what the kerbal community used/developed when sandbox was the only option. I rather liked it and felt it was 'the right amount of limitation', except there was no real way to specify "how limited" you should make your tech (I launched way too many missions to Mun and Minmus in attempts to reduce the numbers and types of boosters). - notes for campaigns: I'd jump straight from orbiting Kerbal to landing on Minmus. Docking is one of the hardest parts of KSP (if you have your career game going, rescuing kerbals is great training). Also working the maneuver nodes to hit other planets is also tricky, you might want to be more familiar with them before flying to Duna. Landing on Minmus really only requires you to know how to adjust your inclination (don't expect it in the notes, I don't think it was inclined when they were written and Minmus itself might be a later addition). - also don't worry too much about "hit a specific continent with a rocket". I suspect this was written before maneuver nodes were included and such tricks really only matter when farming Minmus/Mun for every last biome. Avoiding the "science grind" is pretty hard outside of sandbox. I'd recommend looking through the mods for things that at least no longer require the "science dance" (I've had one that automatically performs and resets experiments if a scientist is on board. Highly recommended [note I haven't tried it with 1.3.2]. Whether you want to make 9-10 landings (each) on Minmus and Mun for all the biomes (expect to need to refuel, but it is pretty easy on Minmus) and how you want to treat the science lab (it can be overpowered) is up to you.

Doesn't this greatly depend on the magnetosphere of the planet? A spacecraft that can use this to be captured by Earth might not be captured by Mars at all. I hope Voyager (didn't only two visit Neptune?) measured the magnetosphere.

I suspect that most air passengers in the 1920s were on short barnstorming flights. That seems to be how they paid for barnstorming exhibitions and kept the planes moving. Richard Bach (of Jonathan Livingston Seagull fame) did this in the 1970s or so and wrote quite a bit about it (note that much of this was certainly fiction).

This is why I was surprised that air-augmentation isn't/wasn't bothered with. But since subs are going to be nearly neutrally buoyant but space constrained, I can see why it didn't happen.

TWR after launch isn't really important unless you are using the fuel to support the mass of the rocket (in which case you might need to reduce thrust). Since F=ma, you are going to have the same stress on the rocket for the same amount of thrust regardless of the mass of the rocket. Of course if you are still in the atmosphere, you might have a nasty maxQ. The shuttle SRBs were designed to specific thrust profile, presumably due to maxQ. Otherwise I'd just expect something like a sawtooth inner ring (for maximum thrust from 0 to outside the transonic regime) and then a constant thrust.

I suspect that will be the reason it never takes off (unless they are side boosters). This screams of something you want more in larger boosters where reduction of total mass (and related structural issues) is a big thing. On the other hand, you would think microsat launchers would be desperate for any more efficiency through the atmosphere.

Wiki claims a TWR of 2.25 (although the wiki isn't clear which configuration has a 73 ton total mass). Sounds like Orbital is tired of gravity losses.

Expendable vehicles make wildly more sense to prototype. I suspect the difference between first article and prototype is largely marketing (the real issue is committing to tooling). If they expect to land the first article a number of times, that changes things dramatically (although I'm pretty sure that only Columbia (first article, enterprise was effectively a prototype) had those problematic tiles).

I'm fairly surprised this was never developed for sub-launch. Presumably the Navy was confident in subs to hide sufficiently close to their targets and that the range was "good enough". As for air-launch, just this Halloween Orbital showed that it is cheaper to use surplus ICBMs to launch your "air launch" vehicles than to redesign them with air augmentation and air launch (Minotaur C is essentially a Pegasus on top of a Peacekeeper booster). It really looks to me like "nearly all the benefits of SABRE (~2km/s delta-v), but much less cost". As much as I'd love to see it on monsters like the BFR and New Glenn, I' fairly sure that "much less cost" isn't remotely "less" enough.

I'm pretty sure some full blown ramjets have been used for that. With at least one downed aircraft. A SABRE engine should get to mach 6 (if it ever gets beyond powerpoint). This gives you roughly the delta-v a reusable falcon 9 stage (they typically stage around mach 6 [although in space] if the booster is returning). A Skylon SSTO would then have to deliver the Skylon orbiter into orbit (along with all SABRE equipment,wings, engine, and fuel tanks). That's a lot of mass to have to accelerate ~7km/s. While it is technically possible, I suspect most investors are either backing space-x or are afraid to compete with both Musk and Bezos. Try installing Realism Overhaul and see some of the problems of spaceplanes (of course, you still miss most of the fun of maxQ and other issues). I'd strongly suspect that a SABRE-powered rocket would still use two stages and that developing low cost reattachment after use makes wildly more sense than SSTO.

Er, no. The stratolaunch plane exists, but hasn't even taxied down the runway under its own power much less flown. There *have* been 38 successful launches of the Pegasus rocket (dropped from either a B-52 or L1011 mothership). There are plenty of reasons why this is suboptimal: the planes used by Pegasus aren't custom and thus can't "top off" cryogenic fuel, thus forcing use of solid boosters/motors, complete inability to scale up rockets without redesigning the entire plane, and general uselessness of the concept (fuel is cheap, planes are not). Generally speaking, this works better for "small launch" such as Pegasus than larger launches, as the square/cube law means drag isn't proportional to mass. The other important thing to remember is that Isp gains (thanks to lower air pressure) are likely to be more significant than avoiding drag losses. I suspect that a high TWR initial stage would also have significant advantages (presumably a SRB, although you might want to be topping off cryogenic upper stages. Using a solid first stage would make that a lot easier). Simply strapping jet engines on to a booster kerbal style would still have considerable issues. Jet (or high bypass turbofan) engines each have a limited range of speeds where they are most efficient and the whole point of a rocket is to pass through each as quickly (or at least efficiently) as possible. I'd further assume that obtaining (presumably possible for DoD/NASA) the engines from the SR-71 would at least allow efficient use from ~mach 1 to ~mach 3. While mach 3 might be significant delta-v (often half the fuel is burnt getting to mach 3), you still have to stage and recover those engines (these are far more valuable than reusable shuttle engines), and we have learned that parachutes don't appear to be a sufficient option (although helicopter capture might just work). A falcon 9 is said to cost $100k in fuel to launch. This is a wildly expensive way to save $50k per launch. Too many things to go wrong, and I really wonder if you could do a heli-capture for less than $50k per snatch, once all the costs are accounted for. I was a big believer in air breathers before KSP. I still am, but I suspect that the tech is much further out than you would suspect and that we could very well get a space elevator before the numbers worked for air breathers.

There's also the issue of SRBs vs. Hydrolox. While the shuttle SRB Isp was wildly better than what you might expect from playing KSP, it still wasn't anything like hydrolox. So even if they were throttling to reduce maxQ, they were also saving the high Isp fuels for after staging the SRBs. Falcon Heavy doesn't have this issue at all, and presumably is also avoiding maxQ issues by (largely) saving the center stage until staging the side boosters (I have no idea what order Delta-Heavy lights the boosters). Without the atmosphere, it would make no sense to save the center booster at all.

Except that current planes have to be fueled with fuel and loaded with cargo that has all of these issues plus COM issues (mostly for the cargo). While I strongly doubt that battery packs will be swapped (compare electric cars vs. fueled cars and planes vs. fueled cars/passenger vs. planes. I'd expect each passenger will require a Tesla-sized battery), most of these issues seem overdone. I'd also expect that inspection can be automatic, as any damage will show up as power/capacity loss during charge/discharge cycles. It really comes down to which the airlines hate more: fuel consumption or mass. Right now the mass can't justify fuel consumption (and remember those turbines are much more efficient than anything in a car, it will take a lot longer to cut airline fuel consumption than just switching to electric).

Presumably FH should be online next year. I'm deeply suspicious of BFR's funding. Don't be surprised if regular Elon time gets to be "Elon time being expended as we scrounge funding". F9 and FH have a real market, BFR's is still questionable. However expensive a Falcon booster is, the cost of a falcon flight is much higher than that. The only reason you won't see many expendable FH missions is the low quantity of missions which require that much mass into GTO/escape velocity. And if you can't find a market for that, you won't find a market for BFR.

I strongly suspect they will fly FH while expending the center booster and get some pretty extreme delta-v that way. That said, it is quite possible that the center booster can handle the severe aerobraking FH will require without too much of a backburn. This is far worse than anything F9 ever saw, but critical in returning the upper stage. Even if it is recoverable without significant backburn, losing that center stage could easily boost payload capacity by more than 25% while increasing costs by ~25% (expending the side boosters would likely be a last resort type of thing).

It is specifically based on the WW2 movie The Dam Busters (1955). They never bothered to come up with their own "air" combat. While Star Wars might not be appropriate for "Science and Spaceflight", it certainly follows from the OP's question. "Maximum Orbital Speed" (unboosted) will asymptotically approach escape velocity (for m/s, but the slowest orbital period) or skim the planet at minimum distance (for angular velocity, but minimum m/s). Since the quote is from Star Wars and the rest of the movie gets *everything* wrong related to space, it doesn't make a whole lot of sense to extract significant meaning from the quote. You can learn "maximum orbital speed" from KSP. Don't expect much from SF movie technobable, and even less from Star Wars. It is of course possible to reach a higher boosted speed (and since the Death Star could exceed the speed of light [presumably, more recently it appears that the stars were packed remarkably close "a long time ago in [that] galaxy far, far away"]).

The low cost of even the expendable falcon 9 makes it look like economics are huge in Musk's thinking (I'll never forget my then Chief Engineer's rant that "cost is a spec"). He might be rich, but the thing has to be self-perpetuating (Bezos might not care, Carmack didn't quite have the mad money to build a space company). But the economic considerations are to keep the thing heading to Mars, not a justification of themselves. On the other hand, I'm rather concerned that the Gigafactory (Tesla's battery building project) will do a lot to stop electric car progress (capacitors and LiFePO4 batteries may be key to Tesla level performance in hybrids. Likewise flow batteries could easy be critical for high range. Don't be surprised to see a "power/storage" hierarchy in power storage, much like the hierarchy used in data storage). Of course, this is one of the effects of making Telsa a public company (the other is making Musk wildly rich, even compared to his paypall fortune) Tesla is expected to primarily make money while Spacex has no such limitations.

And then only roughly 10 times (although more than 1 in 10 missions call for fully expendable launches, so this is unlikely to really be tested).

Only after I've tried a few ways to use the wing surfaces as heat sinks. That's a lot of surface area with a lot of air moving across it. I might even get lift if I just use the lower surfaces. No idea how often ground personnel touch the wings, but at least it is a controlled environment.

There are also claims that Harrison Ford ad libbed it because George Lucas's writing was so bad (most of the rest were better than the script, but whoever came up with this botched it). We are dealing with a universe that: Has fighter spacecraft using aerodynamics in space Lasers move slow enough to observe their propagation Sound travels in space light sabres exist (don't ask everything that is wrong with them) [and with the newest movie] Interstellar distances are next to nothing. While I'm sure I missed plenty of other howlers, there is no reason to believe that the "parsec" blunder wasn't just Star Wars being Star Wars. While "maximum orbital velocity" is effectively escape velocity (and initial capture velocity) I don't believe for a second it isn't just thrown in there to sound good. If you want to geek out about something, I'd recommend something that at least tried to be consistent ("this is your father's light sabre [he killed 30 children with it]").