p1t1o

The new hotness is "Jaff". Jammed-Chaff. Modern ECM suites use phased array anntennae which give excellent control over where the signal beam goes. You point a tight (as tight as these things go, you know, physics) beam in a favourable direction (ie: behind you, where your chaff is going) and eject chaff into it. Naturally, care is taken not to point this beam directly at a known enemy sensor (unless of course you want to jam it conventionally.) Now the ECM broadcast is not coming from your exact location, helping (nothing is absolute in this game of arms-races) to spoof Home-on-Jam-capable weapons and your chaff is shining like a star, increasing its conventional effectiveness. It also serves to somewhat offset the rapid deceleration of the chaff (since its reflected ECM can obscure its velocity/range to a sensor.) Much of this has been enabled quite recently (last couple of decades) due to advances in processing power, beam agility and shaping. A simplistic explanation but that is where the tactics are going. **** During last-ditch encounters, chaff and flares are often ejected together because you never really know what has been fired at you (there are some surprising long-ranged IR guided missiles today and medium-long-range radar guided missiles are handy even in a short range scrap as they have a TON of kinetic energy for manoeuvre and are FAST). Launches at longer ranges are more problematic as it is rarely possible to even detect the launch. There are such things as Missile Launch Warning Systems but they are not perfect, in fact quite limited and can be prone to false-positives. But you might, say, employ a "camoflage" scheme if flying within range of known sensors, ie: when in such and such an area, ejecting a chaff every 10 seconds or so, just to screw thigs up and make it harder to resolve you and elongate engagement times, as a precaution. There are exception to all this and the avionics can help by automating a lot, but really, if you are down to using chaff or flares to save your aircraft or having to actually *dodge*, you are in deep doo-doo already. Clean pair of pants at a minimum. Modern aircraft are geared towards avoiding being there in that situation first place, in BVR or a dogfight, by using energy management and large and small scale manouvre and tactics, as their primary defence, everything else is a thin film of prayer. I mean, we are talking about a type of combat which is *exceedingly rare* these days, and it has *never* occurred between any pair of cutting edge (say jets designed post-1990) modern jets outside of training. Much of this is theoretical.

There is no single barista in the UK apparently, that knows what a cappucino is. Yes I am absolutely an unashamed coffee-snob. Go on, go and order a latte and a cappucino from anywhere and see if you can tell which is which. If they have enough milk in the fridge. A cappucino is a shortish drink, with a little milk so as to be lighter than a neat esspresso as it is traditionally a breakfast drink (as the first coffee of the day its easier on the stomach, but still strong enough to give you a kick up the backside), with foam on to keep it warm as you relaxedly sip it (not down it). It has *equal parts* esspresso, hot milk and foam. 99 times out of 100 if you simply order a cappucino in any given cafe (even major ones) you get a gallon of warm milk with probably some coffee in but Im not sure, its always hard to tell. Just like when you order a latte (which literally means "milk" - order a latte in italy and thats what you get. A glass of milk.) This has been exhaustively tested and my coffee order has been tailored and refined over more than 20 years of cafe-going. The kicker is that since "an esspresso with a little hot milk" is technically a two-part order and off-menu in most places, about 50% of the time they even get this wrong. But going from 99% to 50% failure rate is a pretty good result in most contexts, so theres that. (and no, a "cortado", "flat white" or "machiatto" are not what Im looking for either, even IF you could find any two cafes that make any of those coffees the same anyway) I just want a danged cappucino....

Well....you asked for an unpopular opinion.... We'd be better off cancelling all space programs beyond earth orbit for a couple of centuries. And limiting near earth orbit operations to those which facilitate earth-surface operations such as comms, navigation and operations against Earth impactors. Its not that we couldnt derive benefit, just that we need more of that down here, especially until we have the materials to make more ambitious space programs a reality. Billions of dollars for very limited (compared to say, what we could achieve on earth with the same resources) science data from another world just isnt worth it. The "spirit of adventure/exploration" just isnt worth it. Caveat - I rarely express this opinion....because rockets and spaceflight are just too danged cool, I can live with expensive data from outer space. But I really believe it. We shouldn't go back to the moon. We shouldn't go to Mars. We should cancel all rovers and probes and close the ISS. For quite some time. Maybe until we have abolished money. Yeah, a while.

Such as? Still cant accelerate hard enough to dodge an unmanned weapon, dont need high G at all for orbital manouvres or travel...? And to add, fluid support or not, spikes are a lot harder to endure than sustained, slower-onset forces, whether it be acceleration or pressure. Lithobraking at least, certainly seems too far of a reach to me. I cant think of how a 10,000G-induced pressure spike would harm you, but I bet it wouldnt be healthy. And the ship would have to be built like a tank to stop the cabin from rupturing and the crew being ejected with extreme force through the gaps in the hull. Even space marine drop pods have retro rockets

No I know all that, it was just for interest and to show that the fluid does actually work and has been tested on live animals. Pretty good proof of concept even if the specific fluid is not suitable for high-G applications. *** It does make me think though - when exactly would humans want to be subjected to high-G in space? Not for travel, as you can get anywhere realistic in quick-smart time using a fraction of a G. You can get to other stars in a fraction of a human lifespan with only 1G. Heck, with a torch drive, you can travel to the other side of the universe in less than 1 subjective century, with only 1G. For combat? Well you will be beaten by unmanned craft accelerating at 400G every single time (we had missiles on the books with this capability in the 1960's, it is fully plausible that more complex craft could replicate or improve on this), not least because they wont be carrying a cubic metre of extra fluid mass (mostly because there are limits to the Gforce a human can withstand even with fluid support). Space fighters (a-la XWings and Starfuries) are an obsolete idea. *** FunFactTM: According to the Star Trek: The Next Generation Technical Manual, impulse engines are fully fledged, open-core fusion rockets. I was always disappointed that when they "went to one quarter impulse" that it was just a warm glow and not an actinic spear of blinding light. Also, you can put the nozzle where you want because A) structural integrity field makes the entire ship infinitely rigid and B) the warp drive works by manipulating the mass of the ship, meaning that altering the centre of mass is trivial for them. (Meaning: we design it how we like, then make the magic work around it) Long story short - star trek is not science fiction. It is what is called a "space opera" since it is essentially normal stories just set in space, none of the plots actually require it to be set in the future flying around in spaceships. Ok probably a few do, but it has never pretended to be realistic, it doesnt need to be.

FunFactTM: In the movie "The Abyss" they feature liquid breathing for deep diving and they immerse a rat in the liquid and remove it again. They used actually real perfluorocarbon, which the rat really did breathe and really did survive. Thats just so that the pressure is equal over the whole contact area, it doesnt increase G-tolerance, only reduces bruising. Which i suppose does increase tolerance in a way. Especially if you have to endure repeated periods of high-G.

I think they use some kind of suspended bearing or "air bearing" where above a certain low RPM, the bearing is actually levitated by air pressure - somehow using the rotation of the shaft itself - in the centre of the bearing? Or something like that? **edit** beep-boop-beep google is your friend https://en.wikipedia.org/wiki/Foil_bearing

Just longer life spans wont cut it, it would take a fundamental change in what we term "society" or "civilisation" almost to the point of being unrecognisable. IMO.

Heres the deal with antimatter. Depending on the matter you use the percentage changes, but either way, you end up with a significant portion (like 10-50%) of the mass-energy being released as gamma rays, which are omnidirectional and cannot be deflected. So your ship ends up being in the way of 10-20% of these gamma rays and must absorb them, as heat. So your ship ends up having to reject heat on the order of 1-5% of the mass energy reacted. That is a butt-load of heat. Here is a very interesting treatment of an interstellar antimatter powered ship: https://web.archive.org/web/20060601234257/http://www.aiaa.org/Participate/Uploads/2003-4676.pdf Goes into a lot of detail about a very interesting hypothetical mission, but most interesting is the treatment of how sensitive the ship properties are to technological improvements (the treatment assumes theoretical maximum performance in all areas using todays materials - not todays science, the physical limits of todays materials) in various areas. Long story short - antimatter engines produce ENORMOUS amounts of heat and the difficulty of fast interstellar travel is extremely often, VASTLY underestimated. BUT.....it *is* technically possible Its just that the reality of interstellar travel, even with the very, very, tippy-toppy-best optimistic projections for technological advancement, sci-fi interstellar civilisations or societies like we have in almost all sci-fi, are not really possible. Space is large, bleak and harsh, and we are very small and fragile indeed and just dont live long enough.

Pffft, everyone knows that the North star is always up-well.

Wouldnt it be possible to take precise measurements of the tidal forces acting on the ship, to tell how deep into a gravity well you were? Combined with a direct observation of your orbital period, you ought to be able to tell the mass of the BH you are orbiting and how far away you are. That sound right?

What if we are not a part of the program, what if we are part of the substrate the program is running on? Then you couldnt be a bug

You dont think the current reality could use a little debugging?

Friends and relationships are hard, thats the bottom line. None of us are actually *expert* at it, we all are muddling through. Not one of us is certain we are doing everything right. But the thing that sticks out for me here, is the idea that you can be "stuck with" friends you dont like. Maybe examine that thought pathway and see how you ended up there. I dont know really, how to make more friends from scratch, out of nowhere - other than simply meet more people. All I can say is that the people that I like most, I stay in contact with, the people I like less, I fall out of touch with.

@DDE Oh yes, Im no stranger to the giant/gladiator, the coolest of the S300 series I didnt recognise the missile at the top - google says thats the famous "Gazelle" - that might be the first time I have seen an actual picture of one. If so, how does it guide in the coast phase? One presumes it has a similar profile to the Sprint - high impulse acceleration with coast. Is it an endo-atmospheric ABM?

Erosion of the rails is a big deal I think. https://www.researchgate.net/publication/3107709_Rail_and_insulator_erosion_in_rail_guns https://www.sciencedirect.com/science/article/abs/pii/S0921509311006009

What a weird problem with a standard part... Could it be that they are right on the Centre of Mass so are actuating but no control moment is commanded? Weird root part choice? other than that, standard suggestions - try a restart/reload, try without mods installed (if any) etc.

Yes, in a more rarified envelope, for sure. Sprint was optimised for low altitude. There is a slightly higher quality version of the image (amongst much more) in the document I linked in my first post.

:blushes: aw thanks man, I dont deserve that For reference, the 2nd stage did use aerodynamic surfaces and it did not have a problem with manoeuvring capacity - however it was exceedingly energy-rich and its mission did not require it to travel far, nor expected to manoeuvre excessively (this was well before manoeuvrable RVs) so drag wasnt really an issue. Thrust vectoring was preferred in the 1st stage - amongst other reasons - due to it needing to make extreme turns immediately upon ejection from the launch tube when it is at a comparatively low speed. Thrust vectoring may have been eschewed in the 2nd stage to save space and weight? Or maybe the conventional surfaces just worked well enough. Unsure. Fine tuning drag and Isp really was not on the agenda in building this missile! Maximising sheer power output was the name of the game, which they succeeded at to a degree perhaps never seen since. Which is one of the reasons I love it so much (and it comes up surprisingly often!) PS: somebody please fricken fix the spelling of "manoueoueouvre", its impossible!

Essentially, the change in energy of the orbit is proportional to the change in total energy of the rocket. Since the KE is proportional to the square of velocity, then the change in the total energy of the rocket is greater when the craft is moving faster. 101kg ship @ 100m/s -> KE = 0.5*101*1002 = 50500J Lets exhaust 1kg of fuel to add 100m/s 100kg ship @ 200m/s -> KE = 0.5*100*2002 = 2000000J Increase of 1949500J Now lets do this at a higher velocity 101kg ship @ 1000m/s -> KE = 0.5*101*10002 = 50500000J Lets exhaust 1kg of fuel to add 100m/s 100kg ship @ 1100m/s -> KE = 0.5*100*11002 = 60500000 Increase of 10000000J Thus, the change in energy of the rocket is much greater when thrusting at higher velocities, planet or no planet. It seems strange - "Where is the second rocket getting free energy from?" It isnt - consider that the second rocket has already been given a ton of KE to get to its higher speed in the first place, it already has more energy. (you can do further maths to confirm this by calculating the KE of the fuel before and after burning, but ugh, maths)

@SuperFastJellyfish One of the best lines ever written - more so because of the implication that it is based on empirical observation

Related information: Missiles are starting to appear on the market with more and more novel methods of increasing lethality. For example, the MBDA "Aster" series of SAMs, includes models with solid fuelled "divert" thrusters (referred to as "PIF-PAF"), which fire perpendicular to the missile body, acting at the centre of gravity, that can fire in the terminal phase to decrease miss distance and increase pK. https://www.mbda-systems.com/wp-content/uploads/2015/07/ASTER.pdf Further details are hard to come by, one presumes much is classified. Luckily much has been declassified about cold war projects (but not everything, mind) so there is a wealth of information here. And as it happens, your scenario describes a niche for everyonesfavorite terminal defence king: the Sprint missile. The sprint missile is essentially the reverse of a nuclear reenty vehicle and thus it manoeuvres essentially in the same envelope. Accelerating at 100G at liftoff, it reaches Mach 10 in about 2-3s. First stage manoeuvring is done by vectoring the main thrust using fluid injection (rather than using physical vanes, cold gas is injected into the exhaust which causes dynamic effects that deflect the main plume). Second stage manoeuvring is done with small aerodynamic fins, much with any other missile. At hypersonic speeds, and in the lower atmosphere, aerodynamic lift is extreme. Sprint could manoeuvre at 50-100G laterally and had to be "de-accuratised" because it kept physically hitting the target warheads (it was intended to detonate a neutron bomb - oh yeah, the Sprint missile is the reason neutron bombs were invented, none of that "preserve the infrastructure" junk - in close proximity, nuclear warheads are surprisingly hard to guarantee a kill). This will be a good read for you, I think: http://www.decadecounter.com/vta/pdf/ABM Research & Development at Bell Laboratories - Project History [1975-10].pdf Sprint missile: Note how it looks pretty similar to a nuclear RV Note how small the 2nd stage control fins are

It saves me a lot of time to just ignore videos and suchlike from social media, so I havent and wont watch the video. Not like a "I wONT" kind of way but in a "why would I bother" kind of way. But oh my no, that information is incredibly bogus, from what you describe. Perfect example. Rough guide - if one has a question on something that is making the rounds on social media, google it. Just google the question and pick the link that looks most like a scientific journal. Put "pubmed" or "ncbi"in the search terms. Ignore anything from any kind of site that people want "clicks" from or any other kind of potential income. When people are paid based on the popularity of their videos, accuracy is FAR from their top motivation. Save yourself some time. For the record - much is still unknown specifically about SARS-cov-2, there just hasnt been enough time for studies to complete yet, but similar coronaviruses (and SARS-cov-2 is not expected to diverge significantly) start to get deactivated at a high rate around 55-56degC. https://www.who.int/csr/sars/survival_2003_05_04/en/

Buffy-1 or Buffy-2? https://www.enzolifesciences.com/ALX-804-128/baff-human-monoclonal-antibody-buffy-1/ https://www.enzolifesciences.com/ALX-804-131/baff-monoclonal-antibody-buffy-2/ I love the internet

Yes, LH2 has its drawbacks, I shouldnt have gotten so hung up on hydrolox when I said What I should have said was "cheaper and simpler to use a larger quantity of more conventional fuels than F/Li/H" I meant to stress that I cant see any advantage with moving [from any given propellant] to F/Li/H when we have propellants which already work, for the sake of a few tens of Isps. Anyhoo, the OP question was "why not F/Li/H" and the given reasons ARE the actual reasons, for better or worse. It keeps blowing off bits of rocket scientist.