Technology Stats Help

[Lynneth]

If I fire a 83 kg heavy cylindric object with 6.1 metres length and 0.3 metres diameter at Mach 450 and assume for theoretical considerations it will not destroy itself due to friction heat...

 

a. Will it be able to receive GPS guidance?

b. If I fire this projectile at said speed at 80 decrees firing angle, will it follow a ballistic trajectory back on earth or will it overcome gravity and leave the planet entirely?

c. Assuming said object consists out of tungsten and we suspend the immunity to heat, how long would it need till the projectile dissolves itself?

d. Assuming said projectile would be fired by a railgun (for ease of calculation, we assume the rails are able to withstand the energy without melting), how much energy would be needed given realistic efficiency of the system.

e. If we drop the assumption rails do not integrate, how much energy would be required now, before the projectile either leaves the barrel or the railgun merely stops working.

 

No, I did not come up with this concept.

 

Mach 450 is 153 km/s, plusminus a dozen m/s or so.

The mass is weird though. 0.15*0.15*pi*6.1 ~ 0.43m³. Divide 83kg by that, get ~192 kg/m³ in density.

That's 0.192 g/cm³. Lithium is the lightest non-gaseous non-liquid material at room temperature, at 0.53 g/cm³, roughly.

Strictly speaking, this rod cannot exist. Unless it's hollow, which would likely result in the entire thing being reduced to dust upon accelerating it to these speeds.

 

Assuming it is made of tungsten, the mass would have to be 0.43m³*19.3t/m³=8.32 metric tons.

Presumably, it'll be accelerated to this speed in a vacuum, ie space, then enters atmosphere after attaining this speed. Upon touching the atmosphere, it is likely to shatter or at least begin breaking up in what little time there is for that to happen. Mind you, that's the pure impact on atmo. Like you hitting water, only you're the speed of an airplane and the water is concrete.

 

Now.

a) is answered by iKrolm.

b) I can safely say that mother isn't gonna come back to earth. Earth's escape velocity is 11.2 km/s.
Fun fact, escaping the sun's gravity from Earth's position needs 42.1 km/s. Guess who's more than 3 times that fast? Our tungsten rod.

You ain't gonna see that one ever again.

c) Presumably, near-instantly upon hitting atmo from space. If one managed to accelerate it to this speed in atmo, the projectile would be busy melting while being accelerated.

d) Assuming perfect, 100% efficiency in the system, accelerating a 8.3 ton object to 150 km/s requires approximately 9.34 *10^13 Joule.
That's 11,253 Joule per gram.

Tungsten literally vaporises when approximately 4,500 J/g of energy are induced. This is twice-and-a-half that.

e) Your everything would literally detonate from the sheer power required to get this thing anywhere close to those mach 450. It's scientifically impossible to build this thing because there's no material in the world capable of resisting the incredible forces. And remember I went by the assumption of 100% efficiency in turning electricity into acceleration via the rails. In reality, we'd get at best 30-40%, more than tripling the energy requirement, your capacitors, the mass of the rails themselves if you don't want them to detonate spontaneously, etc, etc, etc.

 

This is literally impossible with any sort of technology that we're likely to see within the next one hundred years.

[Triyun]

http://www.rand.org/pubs/monograph_reports/MR1209.html

[TheShammySocialist]

What, may I ask, brought up this question, Evangeline?

[Evangeline Anovilis]

What, may I ask, brought up this question, Evangeline?

You really want to know? There are people that seemingly tried to argue this as possible.

[TheShammySocialist]

You really want to know? There are people that seemingly tried to argue this as possible.

 

loltech I say. :awesome:

[Evangeline Anovilis]

loltech I say. :awesome:

Is what I said too. But came here, because I knew people like Lynneth got a more profound understanding of the matter.

[iKrolm]

New weapon tested on time

Mendez Barbosa himself attended the testing of the new bomb near the North Western region of the country. The blast had devastating effects on the local area and nearly blew out every window within a 100 mile radius. With it's successful test, the bomb has been placed into mass production immediately.


The massive fireball from the test site, the new bomb will be used in several battlefield situations and remove the need for biological and nuclear weapons.

Hey Greywall, a nuclear blast simulator is telling me that you would need the equivalent of over 100 million tonnes of TNT to 'break every window within 100 miles.' I don't think this is feasable without nuclear weapons.

[KaiserMelech Mikhail]

Hey Greywall, a nuclear blast simulator is telling me that you would need the equivalent of over 100 million tonnes of TNT to 'break every window within 100 miles.' I don't think this is feasable without nuclear weapons.

Isn't the limit for bombs 20 megatons (1/5 the power of that)?

[Evangeline Anovilis]

Hey Greywall, a nuclear blast simulator is telling me that you would need the equivalent of over 100 million tonnes of TNT to 'break every window within 100 miles.' I don't think this is feasable without nuclear weapons.

I'm pretty sure that you can break all windows with less. The 50 megaton Tsar Bomba broke windows that were as far away as 900 km.

 

Isn't the limit for bombs 20 megatons (1/5 the power of that)?

Nope. If I wanted to put my full 400 megatons into one bomb, I can do that. May mean that I'm hardly able to find a bomber to transport and drop it (there's hardly a missile able to fire it), it'd be a huge SDI gamble and every idiot can missile spam the strategic bomber, but I could.

 

For conventional weapons, like the one above, I'd argue that it is pretty much impossible to reach 20 megatons. Even at a TNT equivalent of 4 (I know no explosive with such great equivalent), you'd need 5 million tons of explosives... for comparison, this is like the explosive used in about 71 million 16 inch HE shell of the Iowa or about 2 million Tallboy bombs.

 

To recreate the blast via FOABs, you'd need over 450,000 of those.

 

As Greywall seems to use conventional explosives, the 100 mile claim seems rather unrealistic though.

[Greywall]

You know guys I honestly don't give a shit, just tell what number you guys wants and i'll change it. I just don't care anymore. 

[iKrolm]

Build a Tsar Bomb or a FOAB and you don't need to invent numbers.

Edited October 8, 2013 by iKrolm

[Triyun]

Isn't the limit for bombs 20 megatons (1/5 the power of that)?

 

No.  You can break down your megatons however you want.  You would need a heavily modded bomber to do more though and your wasting ammo.  

[iKrolm]

Also those ICBMs would have to be liquid fuel to do the type of targeting you did, which means they take a while to fuel up, and you rarely keep them underground so they'd be exposed on launchers.

In the technology stats thread because I don't need a GM ruling, I'm just curious: what kind of targetting requires liquid fuel instead of solid rocket fuel?

[Evangeline Anovilis]

If he targets objects this far away, he will have to use a liquid-fuel rocket, because solid-fuel won't do it? My guess.

[Triyun]

You can't do much range adjustment on solid fuel.  Once you burn it burns till its done.  So you can't use the same missile for an IRBM and an ICBM if its solid fuel which is what he was doing.

[iKrolm]

Got it, thanks!

[Lynneth]

deployment of ten new large integrated geo based IR surveillance systems, and the deployment of a supporting bandwidth system to share capability with war fighters for tracking of IR objects from deep space down and fusion with terrestrial based platforms in particular ship, ground, and air breather war fighting systems.

 

Triyun, would you mind terribly explaining in plainer terms what exactly that thing's capabilities are? Especially the second half is confusing me a little.

Thank you in advance.

[Triyun]

The satellite creates an incident report which orients sensors onto a target area for further analysis.  I.E. if an object takes off with significant thrust or there are severe water disturbances, things such as these, that would be analyzed within the Tianxia battle network and compared against our analytical models.  This would be done by computer because its to support the war fighters rather than the national strategic mission, then within second the battle network in the area of air based, land based, and sea based radar and imagery sensors would be oriented onto the area, and distances would be caculated based on things like thrust to home in on an object rather than looking for a needle in a haystack, and anomalies could be distinguished as ones which bear closer scrutiny.  

[Lynneth]

In regards to this thread (though not specifically that post, it was just in range for linking),

 

Cochin, I would like to interject something in regards to the loop you're wanting to build.

Though I might at previous times have said that a Launch Loop needn't be built directly on the equator, I have since come to udnerstand that as wrong. Excessive amounts of resources would have to be invested permanently to maintain the Loop if it's not located directly on the equator, even if it can theoretically be built a few degrees off to the south and north. Practically, having to keep that thing in position would require wasting way more material than is economical. It'd be a giant resource-sink, in short.

 

Furthermore, as Space Elevators cannot be built off the equator either, Tianxia wouldn't be able to operate its elevator all that easily.

 

Adding to that (again because of a new understanding since the last time and whatnot), the 'deflector' stations at each end are very big, requiring a diameter of approximately 16 kilometers, far larger than Foammulah island (which is ~4.6 km long) and too big for an artificial island, in my opinion. I do not believe that any of the launch loops built in CNRP to date, other than the one in Brazil - overland - would have been possible or very stable.

 

Just my 2 cents.

[king of cochin]

Ah! Hmm, might as well shelve the plans for launch loop then, not worth the bother. Next try for Star Tram

 

:)

[Lynneth]

A better and cheaper investment, yes. Though Gen2 might be unachievable for the time being.

[king of cochin]

Gen 1 ought to be enough for me :)