For Questions That Don't Merit Their Own Thread

[Dr. Kerbal]

well. how much dv does it take to get to duna on a not transfer window? cause my next tranfer windows is like in a year.

[Entropian]

That really depends.  Relevant article on Wikipedia: https://en.wikipedia.org/wiki/Porkchop_plot

[wumpus]

21 hours ago, Dr. Kerbal said:

I have looking into electron propulsion do you think there is such thing. Im thinking that you can shoot electrons with magnets and lasers to create propulsion. then use magnets to create a negative froce feild so the electrons dont return. since electrons are electricity so an infinite propulsion system. will that work???????

[I seem to be ninja'ed.  but I'll post my meandering post anyway in hopes that it will provide other perspectives on the issue].

As people have noted, electrons aren't infinite.  You typically have equally many protons as electrons, and when you accelerate a positive ion with equal energy, you get far more momentum.  Momentum is what you need for the rocket equation.

On the other hand, there is no theoretical limit to the amount of momentum you can add to your positive ion through additional energy.  The LHC provides roughly 55 million times the momentum than you would get if you plugged the speed of light into your (non-relativistic) the exhaust velocity of the rocket equation (the one that uses Ve instead of Isp).  I suspect that this might be even less efficient than LED propulsion (especially since the LHC wasn't designed with this as a goal, but even if you designed a cyclotron this way...), but you really aren't limited to your reaction mass if you have arbitrary amounts of energy.

On a small scale, ion engines work this way, and yes they do get the Isp they get in KSP.  Unfortunately, they don't get the thrust they get in KSP, as KSP won't accelerate time for "continuous burn between planets", so you'll have to ignore that.  But the Dawn spacecraft had a delta-v of 10km/s *after* being launched into escape velocity and an Isp of 3100s (the kerbal equivalent is ~4000s).  At the point there is little use optimizing for higher Isp unless you are trying to replace xenon (unbelievably rare) with argon (there's more argon than CO₂ in our atmosphere.  At least  I hope that's still true:), so nobody seems interested in accelerating ions even further.  More important issues are mN/W (thrust efficiency) and increasing thrust overall (despite Dawn's champion acceleration status, she could only do a 0-60mph run in 4 days).

[ARS]

So I've been from Youtube recently and I stumbled upon this phrase:

"We cannot make a new ship anymore because all major corporations put DRM on their ships..."

Could you actually DRM a ship so it can't be reverse-engineered? I'm not talking about the software, but the actual, physical design of the ship (or any other vehicles and stuff that isn't a software) that's being sold commercially being sold with built-in copy protection so no one can copy it. Because if I recalled correctly, back then the Soviets managed to make a carbon copy of American B-29 that crash landed on their soil (which later designated as Tu-4) without any of the original design drawings  whatsoever and simply make their own drawings by measuring the real stuff. Could there be a way to DRM the vehicle to prevent this kind of reverse engineering?

[DDE]

1 hour ago, ARS said:

Because if I recalled correctly, back then the Soviets managed to make a carbon copy of American B-29 that crash landed on their soil (which later designated as Tu-4) without any of the original design drawings  whatsoever and simply make their own drawings by measuring the real stuff.

Yeah. But I have an even funnier story for you:

Spoiler

This is a T-34 turret as built in Stalingrad in September 1941 with some modifications from the plain vanilla Kharkov one:

And this... is what the Stalingrad guys were building once evacuated to Nizhnyi Tagil. They lost all of the documentation for the turret and rebuilt the design from memory while making major improvements.

Assuming comparable levels of scientific development and engineering, "DRM" can come either in the form of material science techniques which are not immediately obvious, or by booby-trapping the vehicle against unauthorized inspection. Everything else is easy to figure out, even if the machine is destroyed in the process of disassembly.

[kerbiloid]

Happily, nothing common even nowhere near.

Spoiler

P.S.
And I just don't want to copy the last two pages of the Chinese launches thread, as it's just an amusing chain of coincidences.

Edited September 19, 2020 by kerbiloid

[DDE]

3 hours ago, kerbiloid said:

Happily, nothing common even nowhere near.

Let's be fair, this was due to instructions from down top, and they've added every imaginable deviation they could get away with within those boundaries.

Starting with the stealth SLS.

[kerbiloid]

Also the Dreamchaser/Bor/Spiral look looks^*) so similar.

^*) Because why mention it in plural form.

Edited September 19, 2020 by kerbiloid

[DDE]

5 minutes ago, kerbiloid said:

Also the Dreamchaser/Bor/Spiral look looks^*) so similar.

^*) Because why mention it in plural form.

Imagine trying to put DRM on a wheel. Or hypersonic aerodynamics.

[kerbiloid]

1 minute ago, DDE said:

Imagine trying to put DRM on a wheel.

Wheel? What's "wheel"?

And btw now I'm thinking...

Could it?

Spoiler

If yes, it's a spacehydroplane.

 

[wumpus]

11 hours ago, ARS said:

So I've been from Youtube recently and I stumbled upon this phrase:

"We cannot make a new ship anymore because all major corporations put DRM on their ships..."

DRM has two means to enforce "digital rights".  First is the legal aspect.  If the DRM contains any encryption, decrypting that code is illegal in the USA under the DMCP act.  I'd assume that you could easily cover all the laws of any major port with enough widely applied legal patches.  It is entirely possible that major shipping companies and the biggest importers and exporters have tied up negotiation to only use their ships to transfer goods.  Then using "un-DRMed" ships would be a contract violation and lead to lawsuits.

But I have a hard time believing that maritime law includes all the craziness of DRM (with the exception of potential contracted monopolies as listed above).  This leads to the question of whether or not you could simply break the DRM.  Quick googling puts the cost of a new container ship in the hundreds of millions of US dollars.  There isn't any DRM that ever existed that you can't break for a tiny fraction of that budget.

I'm pretty sure that 1980s ship technology (back when my dad was raving about his "sea container" stock) would be reasonably effective today.  You might need quite a bit of automation to keep the amount of crew to a minimum (even on an Indonesian payscale), but nothing that can't be duplicated reasonably easily.  If the engines are using that godawful mixture of diesel and paraffin, I can't imagine that engines have changed much since 1900, and certainly not since 1960.

One potential counterexample would be a presumably fixed 737MAX, although you could easily break the DRM and copy the software significantly cheaper than whatever Boeing is paying to fix the issue.  Similarly, while Kerbaloid's image of the Buran appears to have main engines connected to the orbiter, as far as I know the Buran made it to orbital velocity with the Energia boosters.  Those nozzles on the orbiter would be the equivalent of the Shuttles OMS.

[kerbiloid]

1 hour ago, wumpus said:

Kerbaloid's

Thou shalt not ping Kerbaloid instead of other users.

[K^2]

On 9/18/2020 at 11:41 PM, ARS said:

Could you actually DRM a ship so it can't be reverse-engineered?

You can make legality of it ambiguous enough for nobody wanting to deal with it. It's the same trick used with software. There are legal ways to reverse engineer almost anything, but you have to set up very clean separation between the project doing the taking apart and the project of putting something based on the findings together, because you have to be able to prove that you didn't copy anything that's legally considered copyrighted. And there are things you can put into your design to make it very, very difficult. For example, an algorithm cannot be copyrighted, but it can be patented. If something in your design depends on a patented algorithm, then reverse engineering might have you violating either copyright by copying or patent by replicating function.

There is some obfuscation you can do on physical level as well. You can hide tool marks or even create false ones to hide how the part was made. But that's a speed bump more than an actual block. Just makes it that much harder to put a replica into production. This used to be a much bigger deal before CNC and 3D printing. If you couldn't figure out a reasonable process for making a part, you're done. But now you can x-ray the part and find some way to replicate it. Might not be efficient, might be too expensive for mass production, but you'll be able to make something that works. And once you do, you can start working on a knock-off part that will do the same thing that you know how to machine.

[wumpus]

2 hours ago, K^2 said:

And there are things you can put into your design to make it very, very difficult. For example, an algorithm cannot be copyrighted, but it can be patented. If something in your design depends on a patented algorithm, then reverse engineering might have you violating either copyright by copying or patent by replicating function.

The whole patent issue is a rabbit hole you don't want to go down.  In 2000 or so, the standard for "obvious" was "obvious to someone so green they couldn't get hired as an engineer" and even getting that proven in court was nearly impossible (there's almost no way it has gotten any better. I just haven't kept up with that side of the issue since).  The real key is something never published.  And this also makes 'anti-reverse engineering patents' so useful (also DRM lockout chips to lockin your supply chain for game consoles, printer ink, car tools, combine harvester oil, you name it) they will demand a unique action that makes so little sense that nobody has published it and the patent gets auto-granted.  And a good patent lawyer can make finding this patent as likely as a needle in the haystack (assuming that is the goal, I'd assume that they would publicly claim a patent or two to stop people from trying to reverse engineer.  The extra "licensed from this shell company we wholly own" patent comes up in discovery.

[DerekL1963]

On 9/18/2020 at 11:41 PM, ARS said:

So I've been from Youtube recently and I stumbled upon this phrase:

"We cannot make a new ship anymore because all major corporations put DRM on their ships..."

Just a suggestion....  Getting your information from YouTube is only slightly better than getting it from an Oujia board or from a random text generator.  On any given topic, there's a couple of folks who know what they're talking about...  But they're vastly outnumbered by the 99.99999% of Tubers who haven't a clue.

[ARS]

57 minutes ago, DerekL1963 said:

Just a suggestion....  Getting your information from YouTube is only slightly better than getting it from an Oujia board or from a random text generator.  On any given topic, there's a couple of folks who know what they're talking about...  But they're vastly outnumbered by the 99.99999% of Tubers who haven't a clue.

The video is a sarcastic one, though. The full (actual) context is:

"Humanity has reached beyond the stars, then the warp gate systems collapsed, leaving many colonies isolated and fighting between each other for dominance. corporations on far reach of the colonies starts to make money from these conflict, supplying warships on several factions. War is just a business from them, and no one can deny or resist it. Since the collapse of galactic warp gates, the technological setback due to the lack of cutting edge technology and sufficient research facilities means that only frontier corporations holding the high-end stuff, which they keep for themselves. Their technology simply too arcane for the low colonies who's fighting between each other, leaving their ships and weapons systems technology safe from reverse engineering"

[K^2]

@wumpus The standard for "obvious" got better due to Google v. Oracle battles, but if you're trying to make it obtuse for use in DRM, lockout, etc, it's just as easy. So as far as relevant to topic, it's all the same. Just a little easier on engineers just trying to make a product.

[kerbiloid]

11 hours ago, DerekL1963 said:

Getting your information from YouTube is only slightly better than getting it from an Oujia board or from a random text generator.  On any given topic, there's a couple of folks who know what they're talking about...  But they're vastly outnumbered by the 99.99999% of Tubers who haven't a clue.

The internet allows to get quick and enough full answer on absolute majority of simple questions.

The internet allows to quickly gather multiple opinions on the question of interest, compare them, extract the parts which all of the opinionators are agreed with, realize their contradictions, and either choose the opinion you are most agreed with, or just keep in mind various hypotheses.

Irl you do the same but with much smaller group of opinionators, and still need to either believe in their competence, or not.
On one hand you sometimes can choose an interviewee, estimating their presumed skills by your life experience.
On the other hand, you have to believe them even when they are wrong while in internet you are not hypnotized by the wise eyes and official titles.

The youtube (as any other video service) allows the greatest ability to see something with your own eyes, instead of believing 3rd party stories.

[JoeSchmuckatelli]

On 9/21/2020 at 12:59 AM, kerbiloid said:

The internet allows to get quick and enough full answer on absolute majority of simple questions.

The internet allows to quickly gather multiple opinions on the question of interest, compare them, extract the parts which all of the opinionators are agreed with, realize their contradictions, and either choose the opinion you are most agreed with, or just keep in mind various hypotheses.

Irl you do the same but with much smaller group of opinionators, and still need to either believe in their competence, or not.
On one hand you sometimes can choose an interviewee, estimating their presumed skills by your life experience.
On the other hand, you have to believe them even when they are wrong while in internet you are not hypnotized by the wise eyes and official titles.

The youtube (as any other video service) allows the greatest ability to see something with your own eyes, instead of believing 3rd party stories.

True - and the discerning individual will look for multiple sources to discover which sources are the most trustworthy. 

 

The problem is that confirmation bias is subtle - and few people are aware of its existence.  So when you have a notion of 'how stuff works' and you find something cool that seems to fit within your preconceptions... It reinforces those perceptions. 

 

Remember this: https://images.app.goo.gl/AzuuUYokvcoMB47r5 ? 

Perhaps not the best example - but I'm trying to avoid the obvious political ones that persist 

Edited September 22, 2020 by JoeSchmuckatelli

[kerbiloid]

17 minutes ago, JoeSchmuckatelli said:

The problem is that confirmation bias is subtle - and few people are aware of its existence.  So when you have a notion of 'how stuff works' and you find something cool that seems to fit within your preconceptions... It reinforces those perceptions. 

The same pronlem I face and irl.
But unlike the irl, in internet I'm reading even people:
1) who are often more informed than my real life vis-a-vis can be;
2) people, which I would not talk to irl due to personal dislike in any direction;
3) people from opposite sides who enthusiastically woge with shovels of uhm... arguments using every possibility to show their opponent's low competence, while irl I should spend much more time to gather all this... err... argumentation to compare.

Especially great are the imageboards. They are best news aggregators.
Once something happens somewhere and is typed in some unknown newspaper, a minute later it appears there in the hope to immediately show that the opponents are total idiots, so this lets to follow the world press just on a single site..

Edited September 22, 2020 by kerbiloid

[JoeSchmuckatelli]

Heh - my favorite is tweets presented as news. 

 

That's some top notch journalism right there 

Edited September 22, 2020 by JoeSchmuckatelli

[DDE]

13 hours ago, JoeSchmuckatelli said:

Heh - my favorite is tweets presented as news.

Yeah, what kind of a person would ever do that?

 

Edited September 23, 2020 by DDE

[wumpus]

On 9/22/2020 at 12:18 PM, JoeSchmuckatelli said:

Heh - my favorite is tweets presented as news. 

 

That's some top notch journalism right there 

To be honest, that's pretty much what the standard of journalism in the US has become.  Formerly you would go out and get a quote from a source.  And ideally, an opposing [edit: quote] from an opposing source.  Because there aren't any facts, just quotes you can get from cherry picked sources to fit your piece.  Tweets just help journalists do the work of themselves and their fired coworkers: they don't need to get the quote, they can choose from plenty available.

Edited September 24, 2020 by wumpus
inlined

[JoeSchmuckatelli]

Okay - new question: what are the vertical - steeply angled tips on aircraft wings called?       (first saw them on SW Airlines upgraded planes, and starting to see them on smaller jets)

How do they affect performance /economy? 

[SuperFastJellyfish]

They are called winglets.  They mitigate the drag from wingtip vortices.