For Questions That Don't Merit Their Own Thread

[kerbiloid]

13 hours ago, magnemoe said:

If you made an large space station it would have an complete ring, obviously with bulkheads, it would be so heavy people moving would have negligible impact even if some event drew all to one location who we know will happen. 

This doesn't depend on shape.
You need more or less same pressurized volume per person, you need to move more or less same amount of things and resources per person, so dM/M should be more or less same for any shape of the station.
And in both radial and axial directions.
But the ring is the least adjustable. Separated modules can be managed accurately.

Have a bath and move 300 kg of water, have a party and move a tonne of humans, have a festival and move hundreds tonnes.
10 k stadium or concert = about a thousand of tonnes.
When all mass this can freely move along the ring, the CoM moves more quickly and unpredictably than when the mass is separated in modules.

 

13 hours ago, magnemoe said:

You can use moving weights like batteries or other heavy stuff or ballast tanks if you want to compensate. 

Moving equipment makes system overcomplicated and less reliable. An inert mass is required, or resource pumping (say, water).
As resources have very low density, so mostly inert counterweights.
As you need as less ballast as possible, the CoM should be as stable as possible. This in turn means that the whole volume should be separated in local sections, i.e. modules.

Also, that's why two arms with modules are not appropriate.
Treating random CoM changes as a random error, the CoM average position is sqrt(N) stable.
So, you need as many separated modules as possible until they become too small or become a ring. Actually, ~10 modules.
(The 3 is bad, too, but it's a game, so it's OK.)

Edited November 23, 2019 by kerbiloid

[HaplessBystander]

On 11/22/2019 at 8:44 PM, magnemoe said:

Well below 0.1 g its kind of pointless, 0.1 g I say its the sweet spot you can do without

Wait, you can get away with an entire meter per second^2 acceleration rate before crew members start to experience slanted gravity? That's ten times the maximum acceleration rate I'd been under the impression was maybe, possibly low enough to not cause problems

Edited January 11, 2020 by HaplessBystander

[magnemoe]

1 hour ago, HaplessBystander said:

Wait, you can get away with an entire meter per second^2 acceleration rate before crew members start to experience slanted gravity? That's ten times the maximum acceleration rate I'd been under the impression was maybe, possibly low enough to not cause problems. 

Yes, I was probably wrong there, probably much lower as 0.01 g. You can compare it to an ship at sea but less of an problem as its tilted one way all the time like the ship has an list.

[Jestersage]

Question: Does anyone know (or can point to a reference) why DOS-8 (zvezda module) have only Zenith, Nadir, forward, and rearward docks, in comparison to Mir's DOS-7? To my understanding, Zvezda is originally for Mir-2, which implies an improvement.

[kerbiloid]

49 minutes ago, Jestersage said:

Question: Does anyone know (or can point to a reference) why DOS-8 (zvezda module) have only Zenith, Nadir, forward, and rearward docks, in comparison to Mir's DOS-7? To my understanding, Zvezda is originally for Mir-2, which implies an improvement.

Spoiler

Afair:

Originally Mir-2/ISS.ru was planned to include three similar Universal Docking Modules (UDM = USM, universalniy stykovochniy modul^j)

Spoiler

As usually, it's derived from FGB of TKS, and has the docking sphere with 4 radial ports.

So, as you can see on the picture above, that unlike in Mir, the habitat module (say, Zvezda) is not a core of the station structure but just a seed where it starts growing, and most parts are attached to the UDMs.

Hence, the habitat module doesn't need so many ports, and you can place RCS engines or something else at its free sides.

The pioneer module Zarya/Dawn and scientific module Nauka/Science inherit same sphere with 2 radial ports, while unlike the OPS-derived Zvezda are also TKS-derived.

Spoiler

 

Edited November 25, 2019 by kerbiloid

[ARS]

Does digital ammo counter seen on many sci-fi weapons (such as pulse rifle on Aliens) useful if applied on real life weapons (where it has enough ammo count to warrant a readout instead of standard issue 30-rounds mag) or is it gonna be useless because soldiers are trained to manage their ammo efficiently enough that they don't need it

[ChrisSpace]

So let's say, hypothetically, that I wanted to artificially ignite a solar storm at least as powerful as that of 1859, aimed at Earth. Could I trigger it with a powerful enough laser shot into the right part of the sun at the right angle? If so, how powerful would the laser have to be?

[kerbiloid]

56 minutes ago, ChrisSpace said:

So let's say, hypothetically, that I wanted to artificially ignite a solar storm at least as powerful as that of 1859, aimed at Earth. Could I trigger it with a powerful enough laser shot into the right part of the sun at the right angle? If so, how powerful would the laser have to be?

Probably, somewhat like that, to be comparable to the power of the sun internal processes.

Spoiler

 

Edited November 26, 2019 by kerbiloid

[kerbiloid]

2 hours ago, ARS said:

Does digital ammo counter seen on many sci-fi weapons (such as pulse rifle on Aliens) useful if applied on real life weapons (where it has enough ammo count to warrant a readout instead of standard issue 30-rounds mag) or is it gonna be useless because soldiers are trained to manage their ammo efficiently enough that they don't need it

If the magazine is not hidden inside the gun, you can use just a transparent window with engraved numbers.

Spoiler

But in the future weapon the gun should be integrated with HUD  (say, an ocular like the one which Luke Skywalker has, or the machine-gunnners in Aliens)

Spoiler

, so it anyway needs some simple electric scheme for that, and a diagnostic display for servicing.

Also the future weapons will be likely equipped with a biometric lock to prevent its usage by unauthorized persons or enemy. This needs an electric scheme, too.

And it can and probably will be equipped with simple self-diagnostics to check its integrity by measuring the parts electric characteristics (resistance and resonant frequencies) to compare them to standard values.
As well, it can quick test the rounds on load, to extract the damaged ones before loading them into the barrel.

As anyway a gunner of future will need many other electric tools (the night vision, the magnifier, etc), probably in sci-fi the future gun electrification is shown insufficiently.

Edited November 26, 2019 by kerbiloid

[ARS]

I have 2 questions:

1. If we build a hypersonic aircraft with specially made cockpit that allows full liquid immersion with breathable liquid, does it allows the pilot to withstand more G-force?

2. Is it possible to build a high altitude glider that glides infinitely? Aka it doesn't use engines at all and only relying on adjusting the control surfaces to glide forever

[StrandedonEarth]

1: Theoretically, yes, AFAIK. 

2: As long as it can find thermals or other rising air masses when needed to boost the altitude, then I don’t see why not. It also depends on the mission: is it loitering over an area or going somewhere? It would be easier to predict thermals when loitering. Solar energy and batteries would make reboosting easier. 

[magnemoe]

18 hours ago, kerbiloid said:

If the magazine is not hidden inside the gun, you can use just a transparent window with engraved numbers.

  Reveal hidden contents

But in the future weapon the gun should be integrated with HUD  (say, an ocular like the one which Luke Skywalker has, or the machine-gunnners in Aliens)

  Reveal hidden contents

, so it anyway needs some simple electric scheme for that, and a diagnostic display for servicing.

Also the future weapons will be likely equipped with a biometric lock to prevent its usage by unauthorized persons or enemy. This needs an electric scheme, too.

And it can and probably will be equipped with simple self-diagnostics to check its integrity by measuring the parts electric characteristics (resistance and resonant frequencies) to compare them to standard values.
As well, it can quick test the rounds on load, to extract the damaged ones before loading them into the barrel.

As anyway a gunner of future will need many other electric tools (the night vision, the magnifier, etc), probably in sci-fi the future gun electrification is shown insufficiently.

Yes, as said you only need this if you can not see how much ammo is left easy and only relevant for machine guns there you can not easy check how much ammo is left. 
note that at least the Germans had ammo counters on fighter planes in early WW2. Some, think it was US tried using different color tracers then low, this painted an huge low on ammo sign on you
All sort of planes and helicopters last 50 years has ammo counters, exception is door guns there gunner can just look at the ammo box. 

One issue for stuff like rifles and pistols is that you might replace an half full magazine for an full during an fight. 
But for any sort of robots including remote operated guns this is pretty much an requirement.
Yes counters is easy to do, the issue is that you might want to replace or top off magazines and forget to reset the counter, its useful if you can not not easy reload. 

Side note, then you read comments like it took 10.000 bullets to kill someone in say the Vietnam war, this is wrong. Or rather you spend 100.000 rounds and killed 10 enemies but you spend 95.000 rounds to pin down the enemy so they could not move, flanked them then they could not move or got help from artillery or air. 

[ARS]

5 hours ago, StrandedonEarth said:

is it loitering over an area or going somewhere? It would be easier to predict thermals when loitering. Solar energy and batteries would make reboosting easier. 

It's just loitering on specific area, but can relocate somewhere if needed. Think of it as a solar-powered high altitude glide drone

[kerbiloid]

4 hours ago, magnemoe said:

you might want to replace or top off magazines and forget to reset the counter, its useful if you can not not easy reload. 

The (detail) between the shells and the spring in the magazine, together with its (rails) are a conductor of discretely varying length.
So, by measuring its resistance → current length of the chain → position of the lowest shell in the magazine, you can every time get actual number of shells inside.
Then no need to reset the counter, it always updates its value on every magazine event, like in Aliens (btw, director's cut recommended, with autocannons, but M41A is also nice).

Edited November 27, 2019 by kerbiloid

[magnemoe]

1 hour ago, kerbiloid said:

The (detail) between the shells and the spring in the magazine, together with its (rails) are a conductor of discretely varying length.
So, by measuring its resistance → current length of the chain → position of the lowest shell in the magazine, you can every time get actual number of shells inside.
Then no need to reset the counter, it always updates its value on every magazine event, like in Aliens (btw, director's cut recommended, with autocannons, but M41A is also nice).

Far more complex than transparent parts / cutoffs. 
The problem is that you have to set how much ammo you have in practice, you will mostly use this with belt feed weapons anyway. 
I wonder if remote weapon stations has them? I assume so as its an remote operated high zoom camera with an gun and having the system counting shots would be easy. 

[kerbiloid]

7 minutes ago, magnemoe said:

Far more complex than transparent parts / cutoffs. 

For machine counting and HUD only.

7 minutes ago, magnemoe said:

The problem is that you have to set how much ammo you have in practice, you will mostly use this with belt feed weapons anyway. 

Round count = conductor length / round width.

Also magazines can be of 50 and 75 rounds.

Spoiler

 

Edited November 27, 2019 by kerbiloid

[ARS]

So... imagine a scenario like this:

Country A and Country B is separated by ocean. They are in conflict. Country B invades country A, ending with nukes that pretty much renders country A no longer existed, the last of the people on that country gets vaporized. Unfortunately, country A has SSBN fleet hidden in the ocean, with enough nukes to render country B no longer exist too. Assuming that:

1. Country B has no knowledge that country A has SSBN, and both countries has no anti ballistic missile technology, how much of a threat that SSBN presents? (Even if it's just a single sub) And if it does wipes the country B, following the counterattack by dead man's protocol of non-existent government, what's the  status of the sub's crew in the eyes of other countries? Hunted by the rest of the world? Does nothing since it's the dead man's protocol of a fallen nation (and well deserved revenge)? Or judged as war criminal? Or what?

2. In real life, if there's a scenario like this, after the war is over, assuming they didn't fire the nukes, and the war ends with intervention from third party, considering that the crew of the sub no longer have a country, where they'll go? Does the sub belongs to them, or they hand it over to allied country or what? Especially considering that they have nowhere to return, yet still possess SSBN's worth of nukes

Edited November 28, 2019 by ARS

[kerbiloid]

In 1960s the US MoD McNamara estimated the "inappropriate damage" to be achieved in a nuclear conflict as 1/4..1/3 of population and 1/2..2/3 of industry loss, and 400 Mt in total delivered for that, what is still far from a "total vaporization".
Currently, when sides have ~1500 warheads on BM and 500..1000 ICBM silos as primary targets to be targetted with 2 warheads each, almost all of them would be spent on silos and military runways outside the cities, so casualties would be ~10..20% of population.
In 1980s the common idea was a "tank run to the Channel la Manche" and opposing it, both with tactical nukes. So the strategic forces would likely not be used at all, as likely after achieving/not achieving la Manche the Channel the sides would sign a peace treaty keeping their BM and using the opponent's population as natural hostages. Of course, this doesn't sound much better for the battlefield nations, but probably all BM and SSBN owners would keep their strategic forces intact, and lose up to several millions of soldiers each, not their countries.

So, a total nuke war would probably throw the ballistic nations back to late XIX / early XX century (as it's hard to fall lower than the steampunk / early dieselpunk tech, mostly handmade) with several tens millions of casualties, but the untouched SSBN would just return to any not destroyed seaport on its coast and would be awaiting for the further commands from the government.

Edited November 29, 2019 by kerbiloid

[wumpus]

15 hours ago, kerbiloid said:

In 1960s the US MoD McNamara estimated the "inappropriate damage" to be achieved in a nuclear conflict as 1/4..1/3 of population and 1/2..2/3 of industry loss, and 400 Mt in total delivered for that, what is still far from a "total vaporization".

McNamara was not known for his ability to determine the effects of the wars/course of said wars he started/entered.

Generally speaking, while I wouldn't be terribly surprised if significant numbers of people survived a nuclear war (even living in belligerent/nuked states), I'd strongly expect that the world economy and technological base would quickly fall to below Renaissance levels.  It takes a lot of tech to run modern resource extraction (all the easy stuff was typically extracted well before 1900) and losing major key bits of modern tech would probably just see the whole thing collapse.

[Clockwork13]

A lot of news outlets have published articles about this:

 

Am I missing something? They all say 70x the mass of our sun but that doesn't seem particularly massive for a black hole.

[Gargamel]

On 11/27/2019 at 1:03 AM, kerbiloid said:

The (detail) between the shells and the spring in the magazine, together with its (rails) are a conductor of discretely varying length.
So, by measuring its resistance → current length of the chain → position of the lowest shell in the magazine, you can every time get actual number of shells inside.
Then no need to reset the counter, it always updates its value on every magazine event, like in Aliens (btw, director's cut recommended, with autocannons, but M41A is also nice).

I love messing around with Arduino's, and this is just the type of project for it.  But I doubt it would be practical (a counter) for a standard "stick" style magazine, as most aren't big enough for the user to not have a general idea of how much is left.  Of course, it happens, but if you are using a drum or box magazine, this device would be very useful.  

or

 

In drum mag, as above, you could put a small sensor and some marks on the wheel(s) that rotate inside the mag, creating a simple rotary encoder.  This would be fairly simple to connect to a display, letting the user know how many rounds have been fired / are left. 

[kerbiloid]

8 hours ago, wumpus said:

, I'd strongly expect that the world economy and technological base would quickly fall to below Renaissance levels.  It takes a lot of tech to run modern resource extraction (all the easy stuff was typically extracted well before 1900) and losing major key bits of modern tech would probably just see the whole thing collapse.

Another thing is that a lot of resources extracted from underground since the Renaissance is already extracted at placed where the humans already live.
And it's much easier to mine the iron from a scrapyard than from ore.

Another significant thing is that the humanity couldn't melt the iron ore till XVIII century (except tiny amounts of pure FeO in very particular places), and was just reducing iron from oxides, slowly getting metal of very poor quality. 
And it couldn't use coal as fuel, it used only charcoal. They were mining the coal to distill out its organic "oil", but the coke was just a waste for them, not a fuel.
In XIX the population and economics have reached the point when the metallurgic oven size became enough large to reach the melting point of the ore, and it was a lot of coke to feed them.
Since then humanity understood how to properly use iron ore and coal, and both are much more widely used than any other resource.

Until XVII-XVIII the humanity had no idea about heat machines, and any industry required a water wheel aside for all kinds of industrial pumps, belts, and hammers.
So, the industry was very limited in the choice of a place,
Since then, simple steam engines were invented, made of that steel, and powering those pumps, belts, and hammers.

And also electricity and chemistry of XIX.

Thus, humanity in XIX has reached the tech level which can be achieved by hands from scratch, and has a lot of already mined resources around.
So, the people must be the characters of The Walking Dead to fall lower than XIX.

5 hours ago, Clockwork13 said:

They all say 70x the mass of our sun but that doesn't seem particularly massive for a black hole.

A non-core blackhole, of intermediate mass.

The thing is: BH of several sun masses appear from stars, BH of galactic masses appeared long ago when the galaxies were just forming.
But the intermediate ones are none of them, so their mass look unusual.
Though, afaik, our galactic core has a satellite BH of 1000 solar masses, which is >70.

Edited November 30, 2019 by kerbiloid

[DDE]

On 11/28/2019 at 8:44 PM, ARS said:

So... imagine a scenario like this:

Country A and Country B is separated by ocean. They are in conflict. Country B invades country A, ending with nukes that pretty much renders country A no longer existed, the last of the people on that country gets vaporized. Unfortunately, country A has SSBN fleet hidden in the ocean, with enough nukes to render country B no longer exist too. Assuming that:

1. Country B has no knowledge that country A has SSBN, and both countries has no anti ballistic missile technology, how much of a threat that SSBN presents? (Even if it's just a single sub) And if it does wipes the country B, following the counterattack by dead man's protocol of non-existent government, what's the  status of the sub's crew in the eyes of other countries? Hunted by the rest of the world? Does nothing since it's the dead man's protocol of a fallen nation (and well deserved revenge)? Or judged as war criminal? Or what?

2. In real life, if there's a scenario like this, after the war is over, assuming they didn't fire the nukes, and the war ends with intervention from third party, considering that the crew of the sub no longer have a country, where they'll go? Does the sub belongs to them, or they hand it over to allied country or what? Especially considering that they have nowhere to return, yet still possess SSBN's worth of nukes

A single SSBN is capable of devastating anywhere between a single city and a medium-sized European country, depending on the design - some of the lower-tech designs have one-three missiles in the sail.

None of the above questions are properly answered - and it's not just because no-one's been prepared for consequences of a thermonuclear war, even WWII with its aggressive "History written by the victors" stance raised them and left them open. Not attacking civilians is the gold standard of rules of war, yet WWII saw numerous indiscriminate attacks purposefully targeting large urban areas, often for the express purpose of decimating the opposing sides' workforce; counter-value nuclear strikes merely take this to the next level.

What WWII also established is that the victors will not be judged for any of the above. The problem you've thrown in is an apparently neutral third size, which in actual conflicts is rather implausible.

Quote

And if it does wipes the country B, following the counterattack by dead man's protocol of non-existent government, what's the  status of the sub's crew in the eyes of other countries? Hunted by the rest of the world?

The Nuremberg tribunal established that the official legality of an order is irrelevant. Considering that the SSBN's job is to generally engage in mass slaughter of non-combatants, this makes them criminals under that logic - however, since, as described above, extreme moral relativism is in effect, this would have absolutely zero effect.

Quote

In real life, if there's a scenario like this, after the war is over, assuming they didn't fire the nukes, and the war ends with intervention from third party, considering that the crew of the sub no longer have a country, where they'll go? Does the sub belongs to them, or they hand it over to allied country or what?

Technically, they remain an operational component of their now non-existent government, and are subject to the same limitations as any active combatants. Technically, the opposing side can attempt to coax a peace treaty from their surviving superiors; upon conclusion of that peace treaty, their allies would normally attempt to intern their ships or even attack them for a 'treasonous' separate peace, as the British did to the French after Churchill read a misleading translation.

So after all that fluff... the SSBN without nukes would likely seek to either rearm at an allied port, or intern itself in a neutral port, thus quitting the war. With nukes? Their duty to commit carnage isn't yet done; I'd recommend mutiny to ensure execution of the primary mission.

[magnemoe]

On 11/30/2019 at 3:13 AM, Gargamel said:

I love messing around with Arduino's, and this is just the type of project for it.  But I doubt it would be practical (a counter) for a standard "stick" style magazine, as most aren't big enough for the user to not have a general idea of how much is left.  Of course, it happens, but if you are using a drum or box magazine, this device would be very useful.  

or

 

In drum mag, as above, you could put a small sensor and some marks on the wheel(s) that rotate inside the mag, creating a simple rotary encoder.  This would be fairly simple to connect to a display, letting the user know how many rounds have been fired / are left. 

Seen the first magazine before, they tend to have an transparent back plate  
not seen the lower one. 
Magazines generates enough problems as it is, an benefit of an double drum outside of being short is that if one drum jam the other should still work at least for some time. 
Now if you already have an computer on your gun, something would would be useful for aiming especially with moving targets an ammo counter is easy to add and you can not see the back of magazine if its very dark. 
But I would probably just add an counter counting up and reset on magazine change but that is less visual cool. 

[kerbiloid]

Transparency is nice for weak humans.
But how should Fedor the Skybot count the ammo left in "his" akimbo pistols?
And what if they are akimbo machine-guns or some drum-n-base guns?

What if they send a Fedinator back in the time to hunt a bad not-Sarah not-Connor?
How should it use human weapons?
Probably, it should have both abilities.

Edited December 1, 2019 by kerbiloid