[amarant]

Dropping seems a lot easier than landing though. And I imagine if your payload is a nuke, missing your target by even a hundred meters doesn't matter much..

Convincing SpaceX to go along with it on the other hand, I think is going to be really hard.

[hef19898]

Yes, of course, guidance systems for ICBMs and with multiple warheads are easy, I forgot.

[kragen]

guidance systems for icbms are literally the exact same guidance systems used for launching satellites into orbit. that's what the 'b' stands for: 'ballistic' means that the reentry vehicles go where i, the launch vehicle, throw them (βαλλω) rather than guiding themselves to the target with onboard thrusters or airfoils or something. the only difference is that you fall short of orbit

https://en.wikipedia.org/wiki/Ballistic_missile

in the 01950s, guidance systems for orbital launch were a very significant engineering challenge. a rocket is almost an inverted pendulum in the sense that it's a long, stiff thing being pushed up from below; even going to space instead of arcing back into the turf near the launch site requires active negative-feedback control. even the smallest programmable computers were too big and heavy to put into space, so they had to use circuits wired up specifically for the guidance and control task. inertial measurement units were artisanally-produced gimbal-mounted things the size of a small child, there was no gps, and cybernetics was in its infancy. my grandfather built guidance systems for icbms at the time, and it was very difficult indeed

now, every twenty-dollar cellphone contains the necessary ingredients, although some of them are artificially crippled by export restrictions, and control theory is a standard course in any undergraduate engineering curriculum, using the inverted pendulum as a homework exercise. and if you're going to spend a few thousand bucks, and aren't north korea trying to circumvent other countries' export restrictions, you can easily get lower-noise imus than the ones that go into cellphones

so yeah, it's easy, even if it wasn't a problem spacex had already solved

[hef19898]

So, ICBMs are easy, hm? Just slapp in some smartphone components? Then why is, e.g. North Korea struggling so hard with them? Sure they have access to some Samsung Galaxy 12 over there.

[kragen]

they're struggling with the rockets, not the imus or guidance algorithms. rockets that can launch things into orbit are at the boundary of being physically impossible; if earth was a bit bigger, we'd have to use a different space launch method

[brippalcharrid]

It's p̶a̶r̶t̶i̶c̶u̶l̶a̶r̶l̶y̶ pretty hard to obtain guidance systems and components or certain types of ruggedized electronics that haven't been deliberately gimped to prevent them from being used in supersonic or exoatmospheric missiles while on the USA Naughty List, and North Korea doesn't yet seem to have an advanced manufacturing base for this that I'm aware of, whereas Texas or Japan would be a different story.

[kragen]

while this is true, the resulting difficulty is often overstated for both political and historical reasons. itar was conceived in a very different technological, political, and economic world

[thereisnospork]

Um yes they are, that's the point. It might have been hard 40 years ago, but it's not today. SpaceX could build a rocket to park a nuke on your front lawn[0], wherever that is, inside about 30 minutes, without breaking a sweat.

[0]Read: at an optimal altitude and velocity for air detonation.

[amarant]

It's not so much that they are easy per se, but compared to what SpaceX does regularly, it's peanuts. A simplified version of what they already do.

Assuming the warhead itself can handle the detonation part, what part of "fly to these coordinates fast, don't brake" do you think would be difficult for SpaceX based on their current capabilities?

[Sharlin]

Sarcasm truly is the lowest form of wit, doubly so when you’re in fact wrong.

Do you really think ICBMs are difficult conditional on being an entity with the infrastructure and degree of expertise and experience in both launching stuff to orbit and bringing it down from orbit (not just from a suborbital trajectory) that SpaceX now has? Ballistic missiles were first developed and deployed by Nazi Germany. Before transistors were invented. They were already developing ICBMs capable of reaching New York. The war just happened to end before they managed to deploy them.

[hef19898]

Oh, sure SoaceX could do it. Right now, they cannot. And yes, guidance systems for multiple warheads, single warheads are a thing of the past, is not easy to get right. At the very least, it is a major development project.