Posts by bombastic bob 10841 publicly visible posts • joined 1 May 2015
"It looks far more than 60%."
just wait until "powers that be" INSIST compliance be MANDATORY... so you should NEVER let THIS kind of thing "become popular" in ANY WAY - or kiss your privacy GOODBYE!
Because... it is the NATURE of gummints to GRAB POWER in the face of a crisis, and THEN... NEVER! LET! IT! GO! AGAIN!!! (encroach, encroach, encroach, as long as you LET *THEM* !!!)
there is NO NEED to VIOLATE YOUR PRIVACY with this.
Just END THE SHUTDOWNS, NOW!
The REAL numbers CURRENTLY show that it's about 50% worse than influenza. PERIOD. Hospitals are even LAYING PEOPLE OFF due to LACK OF DEMAND!
Why are we shutting down for something that's ONLY 50% WORSE THAN INFLUENZA? We are WAY PAST the peak where it MIGHT have overloaded the medical system.
So, WHY ARE PEOPLE SO WILLING TO GIVE UP THEIR PRIVACY AND BE TRACKED???
WE HAVE the EQUIPMENT, and WE HAVE the MEDICATIONS.
JUST *FEELING* *END* THE *FEELING* *SHUTDOWNS* *NOW* DAMMIT!!!
(and stop acting like a bunch of RODENTS "Hunkering in the Bunker")
why are NASA wasting so much on high-end GPU machines and 3D enhanced goggles
a) spend it all, or lose it in next year's budget
b) someone's brother in law or friend owns a company that...
c) looks good in ads, brochures, and presentations
d) cool toys for engineers to play with [so you don't have to pay them as much]
e) expensive stuff justifies begging for bigger budgets
and so on. It's hard to put a direct finger on it, but I'd say ANY gummint contract is likely to have an element of waste, fraud, and/or abuse in it.
a few years back, when 3D movies started to regain popularity, I wrote an application that lets you take simple 3D photos and produce an anaglyphic (in this case, red/cyan) image from two side by side photos. The idea is to be able to produce the combined image from an imperfect pair, and the image on one side can be moved around a bit to try and accomplish this - ad when you like it, you save the resulting anaglyphic image.
I put several demo photos on a web site, from shots at the hoover dam [the 3D shot of the generators is pretty impressive] which I literally did by moving the camera 1 foot to the right and taking a 2nd shot of the same basic view. no tripod, just had my arms braced against a rail.
Also I had written a slightly improved starfield screen saver, simlar to the one that came with windows, and I added anaglyphic 3D t that - stars whizzing past your head, kinda fun.
Anyway, a resurrection of simple [yet effective] anaglyphic 3D is kinda fun. Sometimes you find that the low tech bandade, spit, bailing wire, and duck-tape solutions are just as effective as spending zillions of dollars on overpriced over-technical "crap" that lines your friend's pockets and looks good in advertisements and presentations, but really doesn't make the difference between success and failure.
(Small startup businesses have to "make do" with hacker-type solutions a LOT, due to a lack of deep pocket investors, just sayin'...)
how to do it: produce red-only from RGB image for left eye, superimose green-blue for right eye into new RGB image. Allow creator to move around and rotate [and maybe even skew] one side so that they line up properly. Then you can slloppy take 2 photos, a foot or so apart horizontally, using the same 2D camera, and later tweek one of the photos a bit and combine them so they look good in 3D. Not hard!
WHAT makes ANYBODY think that THIS kind of TRACKING CRapp on YOUR PHONE is a GOOD THING???
And THIS sort of thing is why _I_ _STILL_ _USE_ _A_ _DUMB_ _PHONE_.
You mightr as wel DELIBERATELY GET INFECTED so you can "flash your WHO immunity card" after you RECOVER [which in 98% of cases, you will]. Oh, don't like THAT idea? Seriously the WORLD has gone WAY TO FAR with this... and GIVING AWAY YOUR PRIVACY AND FREEDOM is NOT ANY KIND OF SOLUTION!
" they harvested login credentials, particularly Windows login creds, from visitors."
Was THIS because of the use of the (strongarmed during setup) MICROSOFT LOGON???
You know, the one that is KINDA DIFFICULT to set up WITHOUT using it (requires 2 or 3 extra steps EVERY! TIME! YOU! DO! IT!), because "The Store" is _SO_ important to your computing (even with that 'updated' windows 8.1 version I did a VM install with yesterday... MSDN yeah, still need it to test things).
Meanwhile EVERYONE (including Intuit) seems to be on board to FORCE YOU INTO THIS SOMEHOW, by NOT SUPPORTING WIN 7 ANY MORE!!!
And I bet that THIS is a CLEAR EXAMPLE why a "Microsoft Logon" is EXTREMELY BAD!!!
yeah, light motion occurs at C and is more of an energy field only where the mass is implied [or imaginary, based on what math you like to use], whereas particle motion has REAL mass and is always less than C.
Momentum and kinetic energy still apply in both cases, of course, but when you travel at C you become light, and so the rules are a *tad* different.
Light has 'rest mass' and is affected by gravity. Einstein proposed it and it was later proved.
Particles without mass like neutrinos are not *entirely* massless, but their probabilities of interaction are so small that they might as well have no mass [for the most part]. But they still have energy, and therefore velocity, and therefore momentum, so go fig.
"not such an easy thing" to explain, eh?
as far as sub-atomics go, there may be actual massless ones, but without mass they can have no momentum, so how do we detect them [even theoretically] since there is no kinetic energy either...
[detecting a mismatch in momentum would detect 'undetectable' particles]
there are other balances, too, like particle vs anti-particle.
in reality electrons exist in a probability 'cloud' that (as I understand it) exhibits some "now you see it now you don't" behavior as well as other unpredictability. My opinion, it's waltzing about through different dimensions, including time, just to make quantum mechanics more difficult for us, heh.
nuclear reactions are all about probabilities, so it's not surprising.
assuming 'big bang' which is likely...
It started at a single point, and everything expanded from there. Using relative velocities it's possible to (more or less) guess where that was.
However...
you have to consider one important fact: When you have an explosion, the energy that is transferred to the things that fly away is not uniform. PLUS, you have momentum and kinetic energy to deal with. momentum (total momentum) is conserved. Kinetic energy is also conserved, and the mass of something is inversely proportional to the square of its resulting velocity [with kinetic energy as a constant in this case]. This is very important for inelastic collisions... which might emit gamma radiation to make up the difference.
Saying that more simply: heavy things won't be going as fast as lighter ones, and if one side has more or less heavy things than other sides, the lighter things on that side may also have different velocities (due to momentum conservation).
So none of this should be a surprise. In fact, 'explosion' kinda implies chaotic results, doesn't it?
It DOES suggest that big bang produced particles of varying mass, from my perspective anyway.
yeah "dishonest politician" - describes MOST of them, especially DEMO[C,N]RATS and ESTABLISHMENT REPUBLOCRATS.
I wonder if they'd EMPEACH THEMSELVES... yeah probably not.
Letting THESE people GRAB MORE POWER during a pandemic is *CRIMINAL* in and of itself. This is reason enough to END THE SHUTDOWNS. [we're ready for it anyway, at least here in the USA, with medications, extra hospital beds, and an emergency supply line for hospital supplies]
(the WAITING and the UNCERTAINTY is DRIVING ME INSANE, as if I could become MORE INSANE than I was, but it seems it's happening...)
looking for straightjacket icon, settling for this
what havent _I_ understood? what haven't YOU understood??!!!
a) the purpose of shutdowns was to prepare hospitals so they wouldn't be overwhelmed. This has been done, MORE than sufficiently [in some places they are LAYING OFF hospital workers, not enough demand]
b) it's a VIRUS, and there's only ONE way to stop a virus: HERD IMMUNITY
c) shutting down for MORE THAN 3 WEEKS ALREADY is MORE THAN JUST EXCESSIVE.
The article gets it right when it talks about people who LOVE THEIR POWER too much that they (essentially) MUST WIELD IT!
And that's the point. We are SUPPOSED to be living in FREE societies, and FREE PEOPLE TAKE RISKS because, after all, we have NOT sacrificed OUR freedom for an ILLUSION of "Safety and Security" - until NOW...
"Has anyone informed the President of this?"
I send him e-mails 3 or 4 times per week since just before that first 15 day period ended, saying "LET US WORK" and things of THAT nature (usually with bullet points as to why). At some point I may start printing letters and putting stamps on them, if that helps get the message across.
Governor "Nuisance" of Cali-fornicate-you also gets FAXes sent from me, usually in LARGE LETTERS (100 point Hulkbuster font of course) saying LET US WORK! END THE SHUTDOWN NOW!
If enough people do this sort of thing, politicians actually worry... in many cases they CAN be recalled (especially in Cali-fornicate-you!).
Trump never really ordered full economic shutdowns. Governors did that. Trump may have to ORDER THEM TO STOP IT though... (it's taking WAY TOO LONG - bad models, too many excuses, and "those who love power": are the biggest problems).
"usable CAPTCHA"
A "special place in HELL" is reserved for those responsible for THAT eldritch abomination! [some re-Captchas just DO NOT WORK AT ALL, 3 or 4 screens of click the photo, or slowly fade-out slowly fade-in photos of 'click the car', and it ALWAYS FAILS, even if you're careful, use a screen magnifier, and wait for each one to complete fading before continuing, and do them one at a time even!]
I've complained, yeah. SEVERAL times. With PROFANITY even. I found the support e-mail address for it [took some searching]. Doesn't seem to have helped much, except that the worst of them aren't appearing as often any more during the COVID-19 shutdowns...
migrating COBOL data storage systems to SQL, at the very least, might be worth while [but requires that time/money thing to do it]
Trying to gerrymander "Object Oriented" into that mix is likely to result in HORRIBLY INFLATED contracts and plenty of job security later on... as in "It is SO Object Oriented that only the author understands it".
Object Oriented = Highly Overrated [and I wonder if those who are responsible for 'those kinds of abominations' could properly DEFINE what 'an object' is, in a single sentence... [it's a nice job interview question that will weed out the "job security" types from your development team]
"I wonder how they did it?"
Chances are, the same way RSA was hit some years ago - low level accountant's login/PC, spear-phished document, allowed scripting when previewing/opening such documents. On WIndows. In Outlook. Or with MS Office. And auto-run scripts aren't completely disabled. And the attachments get "clicked on" in the e-mail. Of course.
It was like a running joke at this one place I was on site - "the accountant" regularly had to have her PC disinfected.
I (and probably everyone else) regularly get these "invoice attached" e-mails with shady 'from' addresses, and of course, documents attached that I must view somehow to get the gist of the message. Fortunately for me, I'm NOT running windows (or in particular, Outlook) when I read my e-mail... NOR (especially) do I view e-mail as HTML [or run a mail reader that PREVIEWS ATTACHMENTS like Virus Outbreak probably still does]. (and don't even get me started on web mail... ugh). If everyone ELSE were to do this, we wouldn't have ransomware problems. General vulnerability would be too low for them to bother trying. "Safe Surfing" in other words.
(and I also save files to disk and USE THE VIEWING APPLICATION ITSELF via "file open" or a command line if it appears to be something legit). "libreoffice filename" (from bash) usually works.
snark aside, I'll just mention this:
Those who give up their [privacy, liberty, freedom, etc.] to achieve SECURITY will get NEITHER.
(actually they'll get CUBA, VENEZUELA, CHINA, ...)
Yeah, it's how COMMUNISM spreads. Don't fall for it. 1984 was a TYPO. Orwell should've said 2020!!
"They" were looking for an excuse, a gap in which to jam their feet in and prop the door open wide enough to get through and INSTITUTE A WORLD WIDE ECONOMIC SHUTDOWN!
And then... CONTROL EVERYONE in the name of "for our OWN GOOD" !!! [these ELITISTS need to be STOPPED, EVERY TIME THEY TRY!!!]
Right now the numbers are starting to say that Corona is REALLY only slightly worse than influenza, so long as it does NOT overwhelm the hospitals and force people to be triage'd. THAT was the justification of the social distancing. But "social distancing" is NOT stopping the virus, JUST SLOWING IT DOWN. Once our systems are UP TO SPEED, we need to LET IT RIP!!! Then, HERD IMMUNITY will kill it off! And, WHEN it comes back NEXT YEAR, and it WILL, you can be sure that WE WILL BE READY THIS TIME!
But SHUTDOWNS do NOT fix this! Keep people working, use common sense, try NOT to spread it when you're sick, but GET BACK TO WORK!!! Otherwise, we might as well *ALL* *DIE*!!!
(this is NOT "the new normal" - this is a FORNICATING CLUSTER-FEEL !!!)
If this "feature" (which I absolutely CANNOT STAND IN CHROME) is NOT the WORST for YOUR PRIVACY, I do not know what COULD be...
(in previous versions I could SHUT THIS OFF, but maybe NOT completely)
a) you type in a URL improperly, IT GETS SEARCHED ON
b) if you type in a local LAN URL, and for some reason it's not resolved correctly, IT GETS SEARCHED ON
c) if you forget an 'http' or spell it wrong, IT GETS SEARCHED ON.
This is AS BAD AS or WORSE THAN CORTANA, if you ask me...
And it's like a FORM of SPYWARE!!!
I'd much rather visit the search engine web site and type stuff into their UI, if there is NO OTHER ALTERNATIVE.
How about a "SHUT THIS CRAP OFF" feature for the NEXT FIREFOX ???
"the DAB signal is patchy, even along major roads. "
That's kinda what I was wondering about. I'm guessing that a digital signal will require Ghz frequencies instead of 100Mhz-ish frequencies (like cell phones, basically) and as such, are more line-of-sight than they are able to penetrate between things and around corners, into canyons, through tunnels, and so on.
My question would've been "how well does it work when you drive through a tunnel". OK even AM can drop out in a long tunnel, but your average bridge or short tunnel won't affect it. FM is a bit more sensitive but generally I don't have problems receiving FM up to 20 or 30 miles from a station. In the USA the FM broadcast is ~88Mhz to ~108Mhz (I'm guessing it's different in the UK).
We will no doubt continue having regular broadcast AM and FM here in the USA but the TV stations have all gone to digital. Antenna reception still works for the digital signals, but is occasionally 'iffy' and pretty much everybody uses satellite or cable anyway.. (and I don't plan on watching TV while I drive)
AM has the advantage of world-wide propagation, almost as good as short wave. Stations have to turn the power down at sunset.
the best retro consoles seem to be RPi-based DIY projects...
a long time ago I started playing with xmame, and with some TLC it should still build and run. So on an RPi (or inexpensive PC for that matter) you (theoretically) should be able to emulate most of the old console games as well as the arcade games from the 80's and 90's.
a few DIY shops sell the joysticks and buttons you'd need to do an arcade-style game. Or you can just get USB game controllers.
Anyway, that'd save a lot of money and make for a fun DIY project. The only thing you're missing is the ability to run those old catridge games, or new games made for the same platform.
Is there REALLY a market for this? Hard to say, but you have to admit the old-style console and arcade games are STILL fun.
seriously, shutting down economies and declaring SOME jobs "essential" and everyone else's "non-essential" so YOU MUST STAY HOME AND TWIDDLE YOUR FINGERS AND NOT GO OUT UNLESS WE GIVE YOU PERMISSION, DAMMIT! - it's LUDICROUS.
practical social distancing - sensible.
wearing a mask if you think you're sick to protect others - sensible
SHUTTING DOWN THE ECONOMIES - *RIDICULOUS*
Here in the USA a short 'pause' made SOME sense, because it gave time to get supply lines up and running. NOW THAT THEY ARE RUNNING, WE NEED TO GET BACK TO WORK, DAMMIT!
So what SHOULD happen:
a) get the extra hospital beds in place
b) get the supply lines running for masks and ventilators and medicines
c) use things like hydroxychloroquine to at LEAST limit the number of people needing hospitalization [and as a prophylactic on hospital and medical staff]
and then... LET IT RIP! BACK TO NORMAL!
we THEN establish HERD IMMUNITY and this BLASTED VIRUS has NO PLACE TO GO!!!
Remember... MOST people don't get serious symptoms. For those who do, we need to make sure there are treatments available.
But... SHUTTING DOWN THE ENTIRE NATION OVER IT? ** NO ** !!!!
NO NO NO NO NO NO!!!!
looks like slack has video conferencing. I have to wonder if it can be done on an android slab...? Or, for that matter, a LINUX desktop computer!
current client got me started on slack - it's a nice way to keep in contact when you do most of your work remotely.
But all we really need is the ability to do streaming video peer-to-peer, and a central server to manage it. I would think open source might have a nice opportunity there... then open up windows for each participant and 'tile' them as needed to view them all on screen.
[seriously does NOT sound all that hard to me... except for the central server part, which would need sufficiently high bandwidth to mitigate firewalled peers]
kickstart, anyone?
"privateer" flag icon - heh
" they just sit there rewriting stuff that was previously working" etc.
It's the "New, Shiny" (read: less attractive/useful to MOST of us) wheel!!!
I once did a parody one-panel comic showing a cave man working on a stone wheel (but not quite finished with it), and a geeky Bill G. type with the older windows logo on his polo shirt, with "Microsoft Wheel", which was octagonal instead of round.
explanation: got it out to market FIRST, even though it was an INFERIOR DESIGN
anyway, for your well-deserved snark, thumbs up!
I am considering moving the one domain I have registered with them. I maintain my own DNS, and if I do not use THEIR DNS servers, they won't support me configuring an IPv6 address for the DNS for ".name" for some reason. It's irritating, and if not fixed, will cause me (this year most likely) to go ELSEWHERE.
After all - I want the 'guru' T shirt from he.net - and unless my DNS servers are registered with an IPv6 address as well as an IPv4 I can't get 'guru' level (nor PROPERLY support IPv6).
(at least it's still cheap through godaddy)
we are expected to abide by any patent a manufacturer in China has on any equipment that is made there, if we make it "on shore". But of course, THEY can do what they want if they don't get caught...
I hear 'made in Mexico' is a cool thing these days, too! [OK I'm 30 minutes away from Mexico so I'm a little biased, but happy to promote manufacturing there for any labor-intensive process that makes sense to build in Mexico]. Competitive prices, too.
There are hidden costs to building things in China rather than your own country. Those hidden costs have become a *bit* more obvious, haven't they?
(don't get me wrong, I like China, but I don't like their government, nor the way that government treats their own people, and the way that government treats THE REST OF THE WORLD)
laptops for work-from-home - and Linux actually makes it EASIER... via ssh, ad-hoc tunnels, etc.. - at least in the I.T. world.
(on a linux desktop it would be *trivial* to run GUI X11 applications remotely, albeit a little slow/cumbersome - using ssh and the DISPLAY environment variable, and a properly configured desktop, and a simple ssh tunnel for the X11 traffic - been there, done that, works pretty well!)
more topic-relevant: broadcom-based devices like RPi being used as "the desktop" for remote access.
"and user rooted devices will block unknown apps by default"
you sure it's not the opposite (or were you being snarky)?
A normal "non-rooted" device blocks un-blessed applications by default, requiring you to jump through a hoop or two to install the potentially "dirty" ones. Some older 'droid versions were actually LESS convenient for doing this, at least on the versions I've worked with [I've had to do it for development stuff a while back, put APK up someplace, have people install it, etc.]. Newer ones have different hoops when you download, but just an extra "yes I want to do this" step rather than changing the default setting to allow 'foreign' APKs or whatever. It's been a while since I did it last... [online instructions if I forget]
But yeah any downloaded APK is a potential disaster for the person installing. The idea that a factory reset does NOT get rid of this particular malware is disturbing. Not sure how to EASILY do a complete re-flash though. It sounds like it would require more than an average tech... [maybe time to research doing that - I never went so far as to figure out how to do a complete re-flash on a 'droid device]
maybe future 'droid devices will need to ship with actual ROM (and not a potentially writable image) for a PROPER factory reset.
/me considers investigating how a debug USB cable might make this a little easier to deal with...
(I obviously STILL have a lot to learn about these things)
and yet - the absolute LAST thing we should want to see is an Apple-like (paywall and/or censor-wall) *STRANGLEHOLD* on what you can or cannot install... _ESPECIALLY_ for independent developers!
ack on that - I haven't tried wget'ting that file, but if I were them, I'd swap it for something that shuts DOWN the virus wherever the infection exists... ok maybe that is a *bit* too 'grey hat' but "I heard a rumor" that "someone did a shutdown script" like that for code-red infected machines {me whistles with innocent look} that basically detected where the penetration attempted to come from, and back-hacked them and turned of ISS [code red sat in memory, shutting down ISS would stop the infection temporarily].
Anyway...
I was just thinking about this, having had the need to have the network guy open up a non-obvious ssh port into a client's network so I could do things remotely. I was thinking of what security things I would need to add, users and passwords to modify and/or lock out from ssh logins, to an otherwiswe normal ssh daemon, how to do it without locking myself out by accident in the process, and things of THAT nature, then I saw this and "It figures, miscreants are out there TAKING ADVANTAGE of little or no on-site staff capable of mitigating such things".
my own system only allows specific users to log in from outside the network, which have cryptic user names and even MORE cryptic passwords. So I wanted to do something like THAT. But obviously I could lock myself out of logging in at ALL if I'm not uber careful.
and, of course, if I do NOT secure it more tightly, some miscreant out there is likely to POUND ON IT with one of those dictionary-based ssh attacks and maybe not get noticed for HOURS... because I had to open it up to an outside IP address as a result of of coronavirus responses by governments.
actually... battery life _IS_ a selling point for laptops, slabs, and even phones.
There are 2 factors to consider:
a) weight/size
b) capacity
You can have a lightweight laptop with lousy capacity. You can also have a laptop with a bozillian hours of operation, but it weighs a lot or is 3 times as thick because of all of the batteries. Then there's replaceable vs soldered-in batteries [a big problem nowadays with slabs and phones at least].
So if you can predict the number of charges on a battery BEFORE you install it, you can (literally) grade them and select "the best" to go in the higher end devices, etc.. and ALSO let people know when it's time to "buy a new one" for the cheap stuff and/or automatically adjust for a repaired device [new battery].
Anyway, this is how I see it. But I also expect that only very new designs will start using something like that, maybe as soon as a year or two from now. [there is a predictable time delay from innovation to implementation and finally getting out to market].
my guess is that it would be hard to use that kind of algorithm with a microcontroller, so NOW "someone out there" will need to produce a charge controller that can be queried [let's say using I2C or SPI] for the charge cycle calculation. That should also work for phones, laptops, and even cars [if it's designed for multi-battery systems].
At least, that's what I'd LIKE to see happen - intelligent LiPo/LiIon charge controllers that can also measure battery capacity.
I worked on something a while back that would estimate battery life using the known charge characteristics, the known discharge current, and the number of 'ticks' it would take to cross specific voltage thresholds during the charge and discharge. It duplicated (more or less) my understanding of the 'smart battery' tech that goes into phones and laptops. Still it was easiest to rely mostly on the charge controller IC to make sure the battery was properly charged and then just intelligently measure things to estimate capacity. [and I don't really want to see the universe encumbered with SOFTWARE PATENTS over this...]
So in my view, THAT is the best place to put this kind of AI batterty tech - in the charge controller, with a way of reading it (like I2C or SPI).
"Wasn't this to be expected now Firefox blocks many trackers by default? Usage will look much lower than it really is if many counters can't count any more."
I like your thinking!!! And, it probably means HIGHER usage for Firefox by the security-minded!
Now if I could JUST get them to ABANDON AUSTRALIS [at least for those of us who HATE it]
{when you can ONLY feed at the pig trough, you feed at the pig trough, but you will RAPIDLY GO ELSEWHERE as SOON as something ELSE is available!}
seems strange (even ironic) to me that a web site that has CVE reports on it would REQUIRE SCRIPT in order to render properly,...
went to see what was up with SystemD, clicked on the link, saw poorly formatted text etc. and noscript telling me that one site had been blocked.
You'd think SECURITY PEOPLE would GET IT, ya know?
if the device you are reflashing a boot loader onto is entirely encased in plastic, it's kinda the same thing, but in my case those devices were only ~$100 each, and not in orbit around Mars. Still for GPL compliance the end-user needed to be able to do the same thing (even worse for breath-holding I think), successfully, or create an expensive paperweight in the process. The only way to attach hardware to recover the device involved drilling holes accurately and soldering wires through those holes onto the board, probably ruining the purpose of potting it in plastic in the first place (waterproofing for ocean operation).
So yeah, major emphasis on "get it right the first time" and (somewhat) necessary nervous behavior and unusual religious activity might be involved.
you might be able to duplicate what happened with a simple experiment
a) pressurize a plastic 2L bottle somehow [specia cap?] using something that's close to its condensation point, like a refrigerant gas.
b) release the pressure rapidly [it will cool the bottle slightly]
c) quickly seal it after venting (a check valve might help)
d) watch the fun
note that gas velocity through the valve will draw a slight vacuum if the valve closes rapidly, due to momentum, depending on the length of the pipe involved. And it cools the place where the gas once was, even more effectively if it can try and condense into a liquid afterwards (like refrigerant).
similarly, (don't try this at home - gutless disclaimer) lighting off alcohol vapor within a 2L bottle through a 9mm hole in the cap might give you a similar effect (it also makes for a fun rocket - distance and safety precautions apply). The velocity of the escaping exhaust through the cap literally draws a vacuum behind it, and the bottle (which quickly cools down the remaining gasses and they have lots of water vapor in them) implodes a bit.
Also...
Rocket fuel tanks are designed to be pressurized because that gives the entire rocket more structural strength, gives positive head pressure [stop it you with dirty minds] for the fuel pumps, and also PREVENTS the 'implode when the pressure drops too low' problem, particularly on launch where compressive stress would otherwise 'accordion' the rocket.
not quite twice the fuel...
a) tanks half full weigh half as much, need half as much thrust from that
b) tanks empty as you burn off fuel, even less required at the very end
c) going up you're accelerating upwards, which has a higher fuel requirement, since it's 1G thrust plus acceleration needs. Coming back, it's less than 1G thrust.
even if the payload coming back is the same (or slightly higher for that matter), it's a fraction of the weight of the fuel. And so the limiting factor here is fuel weight for the return trip, which will be considerably LESS than half of your fuel.
In an ideal scenario I would venture to guess that the going up fuel would be 3 or 4 times the coming back fuel. Then you add a safety margin. So maybe 1/4 to 1/3 of the fuel is for coming back SAFELY, a bit less than 1/2. But still significant.
The Register 
Biting the hand that feeds IT
Copyright. All rights reserved © 1998–2025
