[katieHaylor (OP)]

Norm asks:

The International Space Station orbits the earth at an altitude of 400 kilometres. The missile that North Korea launched reportedly reached an altitude of 2,500 kilometres.

Why didn't it go into orbit around the Earth?

Can you help?

[Janus]

It's not just the altitude, it is also the velocity.  The ISS is traveling at 7.6 km/sec in its orbit. That's how fast it has to travel to orbit at its altitude The missile, in order to travel 2500 km high was launched at a speed of ~6 km/sec and so didn't even have enough speed to begin with to maintain an orbit, and lost speed as it climbed.   So even though it surpassed the ISS in altitude, it never had the velocity needed to maintain an orbit at any point of its trajectory.

[jeffreyH]

What would be the consequences if a North Korean missile hit the ISS?

[timey]

What would be the consequences if a North Korean missile hit the ISS?

War...

[Bored chemist]

What would be the consequences if a North Korean missile hit the ISS?

War...

Probably not a very long one.

[chris]

I liked Donald Trump's tweet to King Dong Un, or whatever his name is: "Hasn't this guy got anything better to do with his life..." - I think that's one tweet that almost the whole world was behind (for once).

[evan_au]

Hasn't this guy got anything better to do with his life...

"Imitation is the sincerest form of flattery" - Charles Colton

Donald Trump is very boastful about "My missile is bigger than your missile". He obviously forgets that in the 1950s & 1960s, both the USA and Russia (as well as UK & France) were obsessed with having nuclear weapons, and the means to deliver them.

This has also played out with India and Pakistan, Israel & Iraq/Iran.

As long as the USA and Russia maintain massive stockpiles of nuclear weapons and ICBMs, you can expect other immature and emotionally insecure countries to imitate them.

Significant reductions in nuclear stockpiles have been achieved through treaties, but they are still maintained at levels that could totally wipe out civilisation - and all it takes is one loose cannon to light the fuse.

One of the problems with land-based ICBMs is that the launch window is very short from the time you detect an attack to the time you have to launch a response (before your own missiles get melted into slag). This leads to dangerous command structures like "The president can launch nuclear weapons without first consulting the Joint Chiefs of Staff, or even declaring war." One suggestion I heard recently was that all countries should decommission their land-based ICBMs (that demand instant launch authorisation from one person) and move to submarine and aircraft-launched missiles, which do not require instant authorisation from 1 loose cannon.

Of course, the USA would be even more uncomfortable with North Korea imitating their fleet of submarines!

See:  http://www.radiolab.org/story/nukes/

[timey]

http://news.nationalgeographic.com/2016/03/you-and-almost-everyone-you-know-owe-your-life-to-this-man/

[evan_au]

reached an altitude of 2,500 kilometres

Due to the high probability of launch failure, most countries try to position their launch site so they can launch over an ocean or desert, so the inevitable failures (and planned dropping of first stage boosters) doesn't land on someone's house or business.

They normally position the launch site so they can safely launch towards the east, so the launch gets a boost from Earth's rotation.

The normal launch profile is a balance between:
- getting out of Earth's thick lower atmosphere as quickly as possible (solution: shoot straight up, then duck when it comes back down)
- gaining the horizontal velocity to reach orbital speed, or reach another country (solution: shoot the missile horizontally - but then atmospheric resistance will give it a very short range).

North Korea does have an east coast, but it faces Japan. Japan, with its high population density would be very unhappy of North Korea dropped missiles on its territory (even accidentally).

So North Korea's solution is to fire the missile almost straight up, but angled slightly so that it lands in the Sea of Japan, between Japan and North Korea.

Rocket builders can check their design thoroughly, and tell a lot about the thrust and range of the missile by the combination of vertical distance and horizontal distance.

North Korea has few choices of launch direction, given the territorial waters of Japan, South Korea, China and Russia, which surround it on all sides.

[timey]

Japan, with its high population density would be very unhappy of North Korea dropped missiles on its territory (even accidentally).

Japan, under international law, isn't allowed to deploy it's army in any type of activity apart from the defense of a physical invasion upon its shores.  If a Korean missile were to fall upon Japanese soil, it is the Americans who are legally obliged to defend Japan in the event of a perceived attack as such from an off shore location.

[homebrewer]

I think that the only realistic answer to combat North-Koreas ICBM'S ,
are Laser weapons in space.

[jeffreyH]

Aim the lasers at Kim Jing Dingaling's head.

[chris]

Aim the lasers at Kim Jing Dingaling's head.

You would need laser precision to find his brain...

[Janus]

reached an altitude of 2,500 kilometres

Due to the high probability of launch failure, most countries try to position their launch site so they can launch over an ocean or desert, so the inevitable failures (and planned dropping of first stage boosters) doesn't land on someone's house or business.

They normally position the launch site so they can safely launch towards the east, so the launch gets a boost from Earth's rotation.

The normal launch profile is a balance between:
- getting out of Earth's thick lower atmosphere as quickly as possible (solution: shoot straight up, then duck when it comes back down)

If you fire the rocket straight up (perpendicular to the ground), it will not come down on your head.  The tangential velocity it picks up from the rotating Earth puts it in a highly elliptical trajectory with an impact point to the East. The Earth rotation also takes your landing path Eastward, but not the same distance. the higher your rocket travels the greater the difference in these distances, and larger the distance between launch and landing measured in the ground frame.

- gaining the horizontal velocity to reach orbital speed, or reach another country (solution: shoot the missile horizontally - but then atmospheric resistance will give it a very short range).

Generally a "gravity turn" trajectory is used.  The rocket starts straight up and then progressively levels out.

North Korea does have an east coast, but it faces Japan. Japan, with its high population density would be very unhappy of North Korea dropped missiles on its territory (even accidentally).

So North Korea's solution is to fire the missile almost straight up, but angled slightly so that it lands in the Sea of Japan, between Japan and North Korea.

With the given top altitude reached for this missile, firing straight up would cause it to land some 700 mi to the East (or pretty much on Japan).  N.Korea actually had to aim the missile slightly to the West, to counter this and have it land in the Sea of Japan.

[jeffreyH]

How reassuring that they actually put SOME thought into their launches. So they should have the correct trajectory to land one on Trump's head.

[Bill_]

As long as the USA and Russia maintain massive stockpiles of nuclear weapons and ICBMs, you can expect other immature and emotionally insecure countries to imitate them.

As far as I know the US still reserves the right to pre-emptively defend itself against any country without nuclear weapons which it thinks is planning to acquire them.

One reason given for Margaret Thatcher going to war over the Falklands was that Argentina had no nuclear weapons.

If N. Korea acquires intercontinental nuclear weapons it will make the world a more dangerous place, but make itself somewhat safer.
Is that being immature and emotionally insecure?
Is it worse than the main nuclear powers who put so much effort into trying to monopolise nuclear weapons?

When Ronald Reagan said "Let's bomb Russia," most people realised he was joking.
If Donald Trump decides to pre-emptively defend the USA against N. Korea it won't be a joke.

[evan_au]

Could a missile go into orbit around the earth?

Emphatically, yes!

That's what the space race in the late 1950s and 1960s was all about.

Increasing the lift of an ICBM rocket allows you to launch a larger atomic bomb farther. But once you can achieve orbital velocity, you can reach virtually any point on the Earth. That may make you feel like king of the Earth.

While military technology was necessarily secret, including the range and payload of ICBMs, this same technology was used in the early space race to very publicly to declare "My rocket/technology/society/political system is better than your rocket/technology/society/political system.".

I understand that after the political purges of the McCarthy era, the USA was psychologically devastated when Russia launched Sputnik into orbit - it carried a radio beacon that could be heard from the USA.

Early US launches were attempted on military ICBM launchers, which failed for various reasons, as portrayed in the recent movie Hidden Figures.

After President Kennedy committed the US to a Moon landing, it was clear that a much larger rocket was needed than any that could sensibly be used to deliver 7 or more atomic bombs to the other side of the world, and so NASA was formed as a civilian agency. But many of the equipment contractors were the companies making ICBMs, and used some of the techniques that had been refined on ICBMs.

Today, heavy-lift rockets are used for launching satellites into geosynchronous orbits, resupplying the ISS, and launching space probes to study other planets.

But another generation of rocket technology will be needed to get a manned mission to Mars and return safely to Earth.

[Bored chemist]

One reason given for Margaret Thatcher going to war over the Falklands was that Argentina had no nuclear weapons.

If "the opposition don't have nukes" is a reason for going to war, why did Galtieri (who didn't have them) attack the UK (who did)?

Also, it's not clear if N Korea having nukes makes them safer, or more of a target.

[Bill_]

One reason given for Margaret Thatcher going to war over the Falklands was that Argentina had no nuclear weapons.

If "the opposition don't have nukes" is a reason for going to war, why did Galtieri (who didn't have them) attack the UK (who did)?

Also, it's not clear if N Korea having nukes makes them safer, or more of a target.

"The opposition do/don't have nukes" isn't the only reason for going to war. Also, for that to work politically, it's best to have some evidence, however spurious, that the country is attempting to acquire nuclear weapons.

Galtieri observed that Thatcher had removed military protection from the Falklands to save money. He thought, probably correctly, that she had no interest in the Falklands, which Argentina had long claimed was its territory. It doesn't seem to have occurred to him that an expensive war to overturn the result of her saving money would make her very popular.

N Korea Korea developing nukes makes them less safe. They seem to be using mobile launchers, so once they have working ICBMS, the possibility of a single missile reaching an attacker's country would at least discourage pre-emptive defence.

Somewhat unrelated, some politicians in countries with even token nuclear defence, like Britain, like the prestige of being in the "nuclear club."

I originally posted because I thought that "immature and emotionally insecure" is a suitable description for pretty much everyone involved in "nuclear diplomacy."

[evan_au]

One irony of the US-Russia Cold War missile competition is that all the early rockets were based on captured German rockets (and captured German rocket scientists) after World War 2.

These rockets were developed under a totally different political system than the two that were vying to show their superiority.