Author Topic: North Korea missiles  (Read 127356 times)

Online hop

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Re: North Korea missiles
« Reply #420 on: 12/02/2017 05:38 AM »
On the other hand, Hwasong-15 seems to have the low performance 4 vernier engine upper stage that uses R-27 verniers, which are not very efficient.
Source? I haven't seen much of anything about the HS-15 upper stage, except that it is very obviously larger than the seemingly undersized one on the HS-14

Offline Chasm

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Re: North Korea missiles
« Reply #421 on: 12/02/2017 06:34 AM »
4 verniers for the HS-15 second stage is a guess based what we saw on previous NK missiles. HS-14 is supposed to use 2 from the 4D10 engine. That analysis is based on tank size and burn time. AFAIK there are no second stage pictures for HS-14 or HS-15.

Looking at HS-14 and HS-15 images and the sizing Norbert Brügge did I really doubt that they intend to use verniers for long if at all. There is much more space this time.
HS-14 had ~1m between ducts. HS-15 has ~4m between ducts. Looking at markings and panels a ~2m long interstage adapter?

I say there is enough room to stick a much larger engine into it. Actually, you can copy&paste the entire first stage engine set -as is- and just protrude 15cm below the painted separation line... :-[

Re: North Korea missiles
« Reply #422 on: 12/02/2017 10:31 AM »
At start second stage of Hwasong-14 may be underpowered with 1.1 thrust to weight ratio which increases over time as fuel is being burned to the point of going over 2.0 T/W and could be same type of situation for Hwasong-15, the point is to drop a bomb which would be a failure if it orbits the earth in first place...

If they want to make SLV version out of it then they will do appropriate modifications to it.

Offline Comet

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Re: North Korea missiles
« Reply #423 on: 12/02/2017 12:16 PM »

Offline Danderman

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Re: North Korea missiles
« Reply #424 on: 12/02/2017 03:21 PM »
On the other hand, Hwasong-15 seems to have the low performance 4 vernier engine upper stage that uses R-27 verniers, which are not very efficient.
Source? I haven't seen much of anything about the HS-15 upper stage, except that it is very obviously larger than the seemingly undersized one on the HS-14

I don’t have a source for the upper stage engines for HS-15, just speculation. It is possible that the upper stage engine is Scud-derived.

BTW, looking at Cosmos-3M as an analog to HS-15 is informative:

https://en.m.wikipedia.org/wiki/Kosmos-3M

Wikipedia says the payload max is 1500 kg. Note the very low performance of the first stage engine, which is related to RD-250.
« Last Edit: 12/03/2017 12:28 AM by Danderman »

Re: North Korea missiles
« Reply #425 on: 12/02/2017 11:15 PM »
I don’t have a source for the upper stage engines for HS-15, just speculation. It is possible that the upper stage engine is Scud-derived.

BTW, looking at Cosmos-3M as an analog to HS-15 is informative:

https://en.m.wikipedia.org/wiki/Kosmos-3M

Wikipedia says the payload max is 1500 kg. Note the very low performance of the first stage engine, which is related to RD-20.

Your comparison is fallacious.

Anyway if this missile can deliver 1,000kg payload anywhere on US mainland so ~13,000km then how light could payload get until it is no longer viable to be sub-orbital and become viable as orbital? 300kg?

Offline Danderman

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Re: North Korea missiles
« Reply #426 on: 12/03/2017 12:30 AM »
I don’t have a source for the upper stage engines for HS-15, just speculation. It is possible that the upper stage engine is Scud-derived.

BTW, looking at Cosmos-3M as an analog to HS-15 is informative:

https://en.m.wikipedia.org/wiki/Kosmos-3M

Wikipedia says the payload max is 1500 kg. Note the very low performance of the first stage engine, which is related to RD-250.

Your comparison is fallacious.

Anyway if this missile can deliver 1,000kg payload anywhere on US mainland so ~13,000km then how light could payload get until it is no longer viable to be sub-orbital and become viable as orbital? 300kg?

you are not quite understanding the proposition.

I made a bunch of assumptions that i hope are reasonable, and noted that the Cosmos 3M was good for 1500 kg to orbit. That would tell us that HS-15 is probably less capable than that, and given the upper stage issue, probably much less capable. That's all.

Oh yeah, there is the problem of surviving re-entry:

http://www.cnn.com/2017/12/02/asia/north-korea-missile-re-entry/index.html

Getting off-topic here, how close is this missile to being able to carry a Mercury-class capsule?
« Last Edit: 12/03/2017 12:32 AM by Danderman »

Re: North Korea missiles
« Reply #427 on: 12/03/2017 12:56 AM »
you are not quite understanding the proposition.

I made a bunch of assumptions that i hope are reasonable, and noted that the Cosmos 3M was good for 1500 kg to orbit. That would tell us that HS-15 is probably less capable than that, and given the upper stage issue, probably much less capable. That's all.

Oh yeah, there is the problem of surviving re-entry:

http://www.cnn.com/2017/12/02/asia/north-korea-missile-re-entry/index.html

Getting off-topic here, how close is this missile to being able to carry a Mercury-class capsule?
I don't care about your proposition which is fallacious comparison, simply incomparable.

There is problem with tbose claims and you, that wasn't MET where its longer, but gradual increase of heat and stress compared to high amgle launch and specialy going 4475km up and down that I am wondering if it went hypersonic before hitting dense atmosphere like splashing the sea before splashing the actual sea or it could be that it was hit by some space debri by some chance. Too many  possibilities.

Edit:
http://www.nationalinterest.org/blog/expert-north-koreas-new-hwasong-15-icbm-you-cannot-stop-23476

Welp... Pixie dust.
« Last Edit: 12/03/2017 01:56 AM by VernierLover »

Offline Danderman

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Re: North Korea missiles
« Reply #428 on: 12/03/2017 04:05 AM »
How does NK monitor the final seconds of flight of these tests? Read newspapers from the West?

Re: North Korea missiles
« Reply #429 on: 12/03/2017 04:32 AM »
How does NK monitor the final seconds of flight of these tests? Read newspapers from the West?
Oh you.

They probably don't care as reentry vehicle went trough much more stress in shorter time span, if it survived long enough to be out of radar line of sight then its probably a success.

Online Steven Pietrobon

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Re: North Korea missiles
« Reply #430 on: 12/03/2017 09:52 AM »
The re-entry vehicle could be just be sending a carrier signal. After re-entry if they still get the signal, they know the re-entry vehicle survived, plus they get Doppler data to measure speed. The re-entry vehicle probably detonates at its required altitude to prevent the vehicle getting into the wrong hands and demonstrate one part of the function required for delivering a nuclear device.
« Last Edit: 12/03/2017 09:54 AM by Steven Pietrobon »
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline Chasm

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Re: North Korea missiles
« Reply #431 on: 12/03/2017 12:15 PM »
The problem comparing HS-15 is that space launchers of similar diameter tend to be ~50% longer.  Call it 45m³ more fuel, more or less what HS-15 has in the first stage.

That said, Norbert Brügge has his 2nd analysis out and he thinks that HS-15 is Unha-3 based.


Mercury-Atlas is out, but a Mercury-Redstone like suborbital hop is possible. Redstone was smaller.
Maybe Kim should forgo Juche Bird and announce a new space race instead.  8)

Online hop

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Re: North Korea missiles
« Reply #432 on: 12/03/2017 07:01 PM »
How does NK monitor the final seconds of flight of these tests? Read newspapers from the West?
In addition to nuclear weapons and ICBM class rockets, DPRK is known to posses ships and aircraft.

Seriously, they've devoted a large fraction of their national economy to this program. There is absolutely no reason to think they are incapable of obtaining observations and/or telemetry from something re-entering over the sea of Japan, and there are very good reasons to think they would expend significant effort to maximize the technical value of these tests.
« Last Edit: 12/03/2017 08:47 PM by hop »

Offline Danderman

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Re: North Korea missiles
« Reply #433 on: 12/03/2017 10:49 PM »
How does NK monitor the final seconds of flight of these tests? Read newspapers from the West?
In addition to nuclear weapons and ICBM class rockets, DPRK is known to posses ships and aircraft.


You are suggesting that deployment of certain ships or aircraft would be indications of an impending launch. That's good to know.

Offline wolfpack

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Re: North Korea missiles
« Reply #434 on: 12/04/2017 03:25 PM »
If he's crazy enough to attempt this Juche Bird test, what trajectory is it likely to fly and where would the IP be? And the global response to an above-ground, thermonuclear detonation?

Any real launch towards CONUS has to overfly China and Russia. How can those two nations possibly be OK with that?

Do we really think DPRK has FOBS capability? IIRC, they couldn't even deploy their last "satellite" properly.

Online hop

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Re: North Korea missiles
« Reply #435 on: 12/04/2017 05:42 PM »
You are suggesting that deployment of certain ships or aircraft would be indications of an impending launch. That's good to know.
FWIW, this is just my speculation as to some ways they could do it, I have no information on whether they do. The main point is that this program is a major national priority and it would be really dumb to do RV tests without collecting data, so the safe assumption is they are set up to collect the data they need.

There have been reports that the IC knew about most of the recent tests in advance. These have generally been attributed to activity around the test site, but tracking assets could certainly be an indicator. OTOH, depending on the exact requirements they might not need anything particularly visible.

Re: North Korea missiles
« Reply #436 on: 12/05/2017 12:59 AM »

Offline Danderman

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Re: North Korea missiles
« Reply #437 on: 12/06/2017 07:27 AM »
Hwasong-15 F-22 tech level http://mengnews.joins.com/view.aspx?aid=3041606

The author of the article does not seem to know much about missile technology.

Re: North Korea missiles
« Reply #438 on: 12/06/2017 04:42 PM »
The Hwasong-15: The Anatomy of North Korea's New ICBM

https://thediplomat.com/2017/12/the-hwasong-15-the-anatomy-of-north-koreas-new-icbm/
Must read!!

Re: North Korea missiles
« Reply #439 on: 12/07/2017 02:57 PM »
The Hwasong-15: The Anatomy of North Korea's New ICBM

https://thediplomat.com/2017/12/the-hwasong-15-the-anatomy-of-north-koreas-new-icbm/
Must read!!
I've read the moment it was released.

Two more successful tests of this missile and you can have a safe bet that if they were to build SS-18 Satan/R-36M class heavy ICBM that it would work on first test and SLV variant would put several ton payload into space.

The author of the article does not seem to know much about missile technology.
The person who said that isn't the author of the article also having single turbopump as evident by single exhaust pipe and have two combustors individualy gimballed is achievement comparable to RD-180 in terms of single turbopump engine with gimballed combustors.

Though would it be more correct to say F-35?
« Last Edit: 12/07/2017 04:43 PM by VernierLover »