Transmissions?
It's kinda hard to make a concrete block transmit anything!
North Korea briefly got its tumbling satellite under control, but before the satellite made any transmissions it started tumbling again. If there was any purpose to the satellite other than to provide a rationale for the launch of the three-stage Unha rocket that lifted it, that purpose won't be fulfilled. As we reported on …
Not necessarily. Depends on what nuke size did they managed to build.
If they did manage to boost a fission device to a few 100kt yield using Sloika or any of the other pre-3rd idea/Ulmann-Teller approaches it does not need to re-enter. It can blow up where it is and EMP-knock out an area the size of New England off the map into the stone age via EMP. It does not need to stabilize - just send it the "blow up" command.
If the satellite is tumbling then any solar arrays used to generate power are going to be pretty ineffective, meaning that the satellite is going to be pretty much reliant on any on-board stored power (in other words, batteries). Unless the Norks filled the satellite with Duracells they will loose power in the next few days.
> any solar arrays used to generate power are going to be pretty ineffective
Not really. Many really cheap & cheerful satellites are simple cubes covered completely in solar cells so attitude control is not a huge issue. And I'm not talking small cubesats.
"Not necessarily. Depends on what nuke size did they managed to build"
The Unha rocket is estimated to be able to lift no more than 150 kgs into low-Earth orbit. As I noted under the previous article, 150 kgs would be a challenging mass limit even to the US, especially if all the kit necessary for reentry had fir within it. There is absolutely zero chance that the Norks can fit anything genuinely dangerous in it.
The "just command it to blow up" bit is also not nearly as simple as you think. First off, the places where Norks might want it to explode above are on the other side of the planet. That means that they cannot transmit the "blow up" command directly. They would need either
a) a functioning comms satellite in a far higher orbit to relay the signal (obviously they don't have one), or
b) precise timer that is immune to effects of both long-term radiation exposure and tumbling (tricky), or
c) sensors to detect when it crosses over the target (tricky in general, absolutely impossible while tumbling)
How much weight and space the physics package requires is totally dependent on the actual design type. I do know the various types and weights and it's entirely possible to fit using more modern designs. What stage they've achieved isn't something I'd know, for now, as it hasn't become public domain.
First off, making nuclear warheads is a bit expensive and takes a while, so even if you have one (or only a few) you're not going to launch it into orbit untill you need it and you're sure you can get it down to approximately where you want it.
Secondly, they don't need to launch anything at all. They just have to plant a microscopic inkling that they might possibly have anything remotely capable of doing any damage approaching that of a leaky fart cushion, so they can blackmail the world into sending them another loaf of bread and a jar of peanut butter, just as they have been doing since the Korean armistice.
"As The Register noted previously, Pyongyang is not believed to have shrunk a bomb small enough to fit inside the Unha rocket, and experts currently don't think the country has worked out how to direct re-entry without the missile breaking up"
A payload of conventional explosive and a few Kg of extremely radioactive material exploding (or even breaking up) over a highly populated area sounds pretty catastrophic to me.
Do they actually need a fully viable device to pose a significant threat if they have long range delivery capability?
"They so much as threaten such a thing the regime will be over within a week"
Absolutely. MAD (Mutually Assured Destruction) doesn't apply here. They could seriously damage the US (or South Korea) with a kludge nuclear device. But only damage. They wouldn't be able to knock out anybody. And retribution would be complete and justifiable in the interests of self defence. Indeed if NORK attacked the US I bet the Chinese would be in Pyongyang before the POTHUS could press the button. They certainly could not entertain a neighbour prepared to use weapons. Only to play with them.
Willy waving in extremis.
> Indeed if NORK attacked the US I bet the Chinese would be in Pyongyang before the POTHUS could press the button
One "interesting" thing (out of many) The Donald said recently, is that if he was El Prez, he'd tell the Chinese "do what you want with the Norks, we'll look the other way"
That'd be worth the extra-large family-size popcorn
China can and has done what it wants with all of its satellite states. Historically, they've been buffer states to protect China from invasion.
China has already cut off supplies, electricity and internet from North Korea over various incidents.
It'd not take much more for China to send their military in to make a fine point with the North Korean leadership.
Not really, all research thus far has found that dispersion of nuclear isotopes are limited to essentially being a mere inconvenience. You'd need metric tons of radioisotopes to significantly contaminate an area beyond a city block - especially if it's from breakup or high altitude dispersal.
Hell, I was born in the early 1960's and am mildly radioactive, courtesy of all of the nuclear armed nations surface nuclear warhead testing. Everyone is.
Juarez, Mexico had a Cobalt-60 spill, one of the worst ever, negligible harm to the populace. Today, it's in steel rebar and table legs all over North America, no harm observed to any of the populace.
At least, not so far. Some people received 150 - 200 rads of radiation and are being observed to see if they suffer any lingering effects.