For Questions That Don't Merit Their Own Thread

[Entropian]

2 hours ago, tater said:

 

Wait, I didn't hear about that.  Meteorite?

 

[K^2]

Always a meteor until proven otherwise, and this one looks like it fizzled out before impact with a few flareups here and there that might correspond to rock falling apart into smaller pieces.

[tater]

 

[JoeSchmuckatelli]

Can a magnet have a frequency?  i.e. can you 'tune' a magnet to prefer other magnets of the same frequency over nearby magnets tuned differently?

Also: if a fighter did a supersonic pass 'on the deck' at an airshow... would it knock folks' socks off?  (i.e. how does the concussive force of a jet's sonic boom compare to say fireworks or tank rounds going off)?

[Terwin]

3 hours ago, JoeSchmuckatelli said:

Can a magnet have a frequency?  i.e. can you 'tune' a magnet to prefer other magnets of the same frequency over nearby magnets tuned differently?

Not exactly, magnets have poles(called north and south), but no sort of inherent frequency.

Depending on what you are after, you could glue together several magnets with a specific pattern of north and south poles such that it would not bind tightly to other magnets with a different ordering
, but that would not stop an iron plate from sticking securely to the magnet.  ('not bind tightly': may not line up properly and should be much easier to separate when they stick together)

Quote

Also: if a fighter did a supersonic pass 'on the deck' at an airshow... would it knock folks' socks off?  (i.e. how does the concussive force of a jet's sonic boom compare to say fireworks or tank rounds going off)?

As far as I am aware, the amplitude of a sonic boom is controlled by 3 things: displacement, speed, and proximity.

A plane with a larger cross-section will generally cause a larger amplitude pulse than a smaller cross-section plane at the same speed and distance.

A plane moving faster will generally displace the air more violently than the same plane at a slower speed.

A recipient further away from the plane will experience a more dissipated shock-wave than one closer to the plane.

 

While I strongly suspect that you could find 'TNT equivalent' for fireworks and tank rounds, I do not think shock-wave details about military planes is likely to be available, and that would represent a majority of super sonic planes of which  I am aware.

Edited December 29, 2020 by Terwin

[JoeSchmuckatelli]

40 minutes ago, Terwin said:

Not exactly, magnets have poles(called north and south), but no sort of inherent frequency.

Depending on what you are after, you could glue together several magnets with a specific pattern of north and south poles such that it would not bind tightly to other magnets with a different ordering
, but that would not stop an iron plate from sticking securely to the magnet.  ('not bind tightly': may not line up properly and should be much easier to separate when they stick together)

Okay - I know about the poles: it's more about this (w/regard to PMGs) "where the electrical energy is generated at a variable frequency related to the rotational speed of the rotor, the output must be converted to match the frequency of the grid."  If we reverse this, and make an electromagnet - is there anything unique or interesting about the frequency of the electricity used that might make the electromagnet different from one of a different frequency?

[kerbiloid]

Why does ATV have two similar control docking targets on the forehead right aside each other, and in all photos and videos only one of them is highlighted?

Spoiler

 

[JoeSchmuckatelli]

Guessing - but given that we used to use parallax sighting systems for targeting, I'd suspect that they give a visual way of determining the distance to the craft other than laser or radar. 

 

 

[kerbiloid]

On ship they have a pair of lasers below the adaptor, at the very edge of the hulll.
And a triangle of passive reflectors below the adaptor of the station.

So, they probably use these targets for reverse visual control of the ship approaching.
The first thought they cause - it's a stereo pair, but I'm puzzled why only one of them (the same) is on, while the other is off.

Also, as this is a modified docking system, for PTKNP, adapted for ATV, we probably could expect same targets on Soyuz MS, using same docking port, but I can't see them on it. 

[Terwin]

10 hours ago, JoeSchmuckatelli said:

Okay - I know about the poles: it's more about this (w/regard to PMGs) "where the electrical energy is generated at a variable frequency related to the rotational speed of the rotor, the output must be converted to match the frequency of the grid."  If we reverse this, and make an electromagnet - is there anything unique or interesting about the frequency of the electricity used that might make the electromagnet different from one of a different frequency?

If an electromagnet is being powered by alternating current, then the poles should be swapping at the same frequency as the current.

This can be  problem if you try to use it to pick up a permanent magnet or an electromagnet that is not perfectly opposite in phase due to violent vibrations as the poles alternately repel and attract.

 

 

[K^2]

17 hours ago, JoeSchmuckatelli said:

If we reverse this, and make an electromagnet - is there anything unique or interesting about the frequency of the electricity used that might make the electromagnet different from one of a different frequency?

The moment you apply AC to an electromagnet, you have to start worrying about induction, and it's a hell of a complicated topic in general. Every piece of conductor near an alternating electromagnet becomes an alternating electromagnet with matching frequency and shifted phase on top of anything else that's going on. The shift in frequency will depend on metal properties, surrounding non-metal materials, and shapes of all objects involved. The frequency shifts can result in the two repelling, attracting, generating transverse forces, and generating torques. And while frequency applied will have effect on all of the above, so much also depends on configuration, that it's nothing remotely as easy as choosing the right frequency for the desired effect.

[DDE]

After these two questions, I'll be on all the watchlists this side of the Milky Way.

Spoiler

1. How would modern handgun ammunition react to being carried around on EVA?
2. Is it possible to reliably work the slide on a handgun in modern or reasonably near-future spacesuits?

Full disclosure, I'm thinking about this contraption:

Spoiler

 

 

[magnemoe]

1 hour ago, DDE said:

After these two questions, I'll be on all the watchlists this side of the Milky Way.

  Reveal hidden contents

1. How would modern handgun ammunition react to being carried around on EVA?
2. Is it possible to reliably work the slide on a handgun in modern or reasonably near-future spacesuits?

Full disclosure, I'm thinking about this contraption:

  Reveal hidden contents

 

 

Don't think its much issues an gun in vacuum, Scott Manly did an video about this long ago. In freefall you obvious has issue the main being the rotation you get if firing an gun and recoil is not along center of mass. 
And yes even if the primer and powder works in vacuum taking an gun out of an airlock its still air inside the cartridge and they are designed to be water resistant so the 1 bar inside is likely to try to push the bullet out of the cartridge so you could easy get jams. And in vacuum the gun will keep heat far longer.  And yes out gassing might be an issue with long term exposure. 

You already have guns with oversize or no trigger guards designed for used with bulky gloves. With no guards I think you have to first push the trigger down from flush with barrel and this act as an safety. 
Now using an scope with an spacesuit helmet is more of an issue  

Now the cocking trigger is the weird thing here as the forgotten weapon guy point it out. Its an nice safety feature as you can keep the gun without an round in the chamber but get one there fast if needed. 
it might be nice for police guns, here in Norway after the ISIL attacks in Europe the police start to go armed, before they left the guns in the car and picked up if needed. 
Well it was lots of accidental discharges. Police is well trained however gun training is probably mostly on the range not in how to carry an gun around. 

Edited December 30, 2020 by magnemoe

[JoeSchmuckatelli]

1 hour ago, DDE said:

After these two questions, I'll be on all the watchlists this side of the Milky Way.

  Hide contents

1. How would modern handgun ammunition react to being carried around on EVA?
2. Is it possible to reliably work the slide on a handgun in modern or reasonably near-future spacesuits?

Full disclosure, I'm thinking about this contraption:

  Hide contents

 

 

Honestly - if you have a chemical reaction that does not require 'air' (read: oxygen from the atmosphere)... it should work in space.  So, just as our rockets work in vacuum, so should weapon propellant.  As noted above - firing a gun in freefall is probably not smart.  If you were on the moon, you could probably learn to position yourself in a way to handle the recoil and employ the weapon effectively.

[TheSaint]

1 hour ago, DDE said:

After these two questions, I'll be on all the watchlists this side of the Milky Way.

  Hide contents

1. How would modern handgun ammunition react to being carried around on EVA?
2. Is it possible to reliably work the slide on a handgun in modern or reasonably near-future spacesuits?

Full disclosure, I'm thinking about this contraption:

  Hide contents

 

 

Another issue you will have: lubrication. If your task is a one-off, no big deal: Your firearm will almost certainly work once if you don't expose it to vacuum for too long. But if you intend to use the firearm in vacuum on a regular basis, you will need to use special lubricants. Normal gun oils and greases will freeze up and/or evaporate in vacuum. Dry lubes, such as powdered graphite, will probably be a better choice, and some firearms will work better with those than others. Also, if your firearm has lots of tight clearances, as most do, vacuum welding could become an issue. On the whole, you will do better with a purpose-designed firearm in vacuum, rather than just pulling one off the shelf.

[kerbiloid]

The dry parts would probably weld together like the spring on the Gemini door (after 20 minutes of exposition, iirc).

So, a graphite lub or so.

The Almazgun was a "special" version, whatever it means. Probably, that's what it means.

***

Thicker fingers - bigger guards.

Spoiler

***

P.S.
Also, disassembling-assembling in space takes more than 19 seconds.

Edited December 30, 2020 by kerbiloid

[K^2]

Simple. Use the laser gun!

[magnemoe]

1 minute ago, K^2 said:

Simple. Use the laser gun!

What is that, guess some sci-fi prop with an laser cartridge. Now the gyrojet would be very nice for long range fire because no recoil, perhaps combine with an pistol under barrel for close combat. 

[TheSaint]

Or a Gyrojet.

Edit: Ninjaed by Magnemoe.

Edited December 30, 2020 by TheSaint

[magnemoe]

1 hour ago, TheSaint said:

Another issue you will have: lubrication. If your task is a one-off, no big deal: Your firearm will almost certainly work once if you don't expose it to vacuum for too long. But if you intend to use the firearm in vacuum on a regular basis, you will need to use special lubricants. Normal gun oils and greases will freeze up and/or evaporate in vacuum. Dry lubes, such as powdered graphite, will probably be a better choice, and some firearms will work better with those than others. Also, if your firearm has lots of tight clearances, as most do, vacuum welding could become an issue. On the whole, you will do better with a purpose-designed firearm in vacuum, rather than just pulling one off the shelf.

Now this is true for all sort of stuff, if things works out like Musk want, well you want all sort of vacuum rated hand tools like drills and angle grinders and up to tools like small earth movers and drill rigs you see at construction sites and all the small excavator all are using. 

[K^2]

2 hours ago, magnemoe said:

What is that, guess some sci-fi prop with an laser cartridge.

No, that was an actual laser gun designed by the Soviets for use in defending Soviet military space stations from US spy satellites. At least a few were made and at least one is in a museum in Russia, but I don't know if any actually flown. The idea was that while the beam isn't powerful enough to do any physical damage, it was powerful enough to blind optics. So if you see an identified satellite trying to do a close approach, you'd aim for whatever looks like a camera and fire. In theory, it could also be used to blind a person, so it could be used as an anti-personel weapon that way, but it doesn't sound like that was considered a likely use case.

The cartridges contained something very similar to flash powder used in the old timey photography. That would pump lasing medium in the gun "barrel" almost instantly causing it to produce a laser beam. Otherwise, it's a fairly standard laser emitter. It's a clever idea for the specific use case. I don't know if the use case itself was ever realistic, but somebody decided it was worth investing some R&D into and so Soviet Union built an honest, fully operational, magazine fed space laser pistol and that's one of these little factoids that makes me happy.

Unfortunately, even if it can be scaled up in power to do physical harm, maybe enough to burn holes in space suits, advances in laser diodes and supercapacitors make it far more practical to power such a laser electrically. So I don't think we'll ever again see laser guns that take a clip of pyrotechnical charges.

[JoeSchmuckatelli]

6 hours ago, TheSaint said:

Or a Gyrojet.

Edit: Ninjaed by Magnemoe.

Soviet era weapons are always a mix of Brilliant, Bonkers and Cheap.

 

Contrast that with this: Brugger & Thomet B&T APR338 - Bing images

 

Talk about over built!

 

Edited December 31, 2020 by JoeSchmuckatelli

[kerbiloid]

6 hours ago, magnemoe said:

What is that

That is what
https://translate.google.com/translate?hl=ru&sl=ru&tl=en&u=https://ru.wikipedia.org/wiki/Лазерный_пистолет

 

[DDE]

Thank you for all the responses, but I was mostly worried about the thermal stability of modern gun propellants.

I was basically thinking about the minimum list of possible precautions, and not carrying a round in the chamber was one of those.

[K^2]

1 hour ago, DDE said:

Thank you for all the responses, but I was mostly worried about the thermal stability of modern gun propellants.

Cold isn't a problem. If the primer goes off, the round will fire. And since primer usually has its own casing, it should be perfectly functional even if it becomes brittle. I am familiar with some primary explosives that can crystalize out in low temperatures which causes them to become more unstable. I don't think that can happen to mercury fulminate or lead azide, but I'm not certain.

High temperatures are a problem, of course, but if it's stable enough to be left out in the sun on Earth, it's hard to imagine conditions where it'd overheat dangerously in space.

I think, if temperature is a problem at all, it's going to be due to making the frame too brittle and possibly failing after a few shots. But I'm confident you can get a single shot out of a firearm in space pretty much no matter what.