Thread: Hypothetical ICBM Question

Here's a hypothetical question:
Could an ICBM, whether with a nuclear payload or not, be targeted to hit an object (say, an alien spaceship haha) that's hovering 30 miles above the ground? If so, in what stage of its flight would it do that: boost phase or reentry phase?
Thanks,
Rconor

Most ICBMs are set to blow up pretty far above the ground (like 2-5 miles), because that gives them the maximum damage area. There's no reason that 30 miles wouldn't be equally possible. That's still inside the Stratosphere (though not by much), so it's not outer space.


Whether it was setup to hit it on re-entry or boost phase just depends on how close the space ship is. If it's located on another continent (which is what ICBM's are for "Inter-Continental Ballistic Missile"), then it would have to hit it on re-entry. If it's closer then you could hit it during the boost phase. You'd probably use a much shorter ranged nuclear rocket for that, however.

Is this for a sci-fi novel?

My question is this.

Do you expect them to stay still for it?

the only problem i see with using an ICBM to take out an alien spacecraft would be that if it were close to us, we wouldn't use an ICBM we'd probably use a SAM launcher. and if it were over another continent, we probably wouldn't be firing at it, they would.

plus, it's never a good idea to detonate a nuclear payload 30 miles above the earth, the EMP blast would wipe out electronic devices over an extremely vast area if that were to happen.

Thanks for the info guys,
Actually, the reason I'm asking this is because of a Model UN conference I'm attending, in which the situation is an alien spacecraft that has come to a hover above Pyongyang, North Korea. According to the "Background Guide" for the committee, North Korea has aimed missiles at the spaceship, and I'm just wondering whether North Korea actually has the capability to shoot down an object 30 miles above the ground. As far as their SAMs go, they have none which have an engagement altitude of 30 miles; I believe their highest-altitude SAM has a range of 24.6 miles (this is altitude remember, not overall range). So I was just wondering if there was some other way they could shoot it down. From your responses, it looks like they could rewire a Taepodong or a Rodong (ICBM and IRBM, respectively) to detonate prematurely in Boostphase before they reach the atmosphere, at an altitude of 30 miles, and in doing so destroy the ship. I say boost phase because North Korea currently doesn't have a viable reentry vehicle, so any strikes would have to be made before the missiles entered the atmosphere.
Am I sounding correct here? I hope I'm wrong, cuz I don't want N. Korea to be able to shoot it down...

This is definitely not a matter of simply punching in new target coordinates. ICBMs have dedicated software that coordinates boost, ballistic and reentry phases to engage a stationary target. Targeting an object 30 miles above a launch site requires totally rewriting the software and probably modifying the hardware. It's a novel concept, and all this requires many months, if not years, of work, including test flights.

Originally Posted by jrmonroe

This is definitely not a matter of simply punching in new target coordinates. ICBMs have dedicated software that coordinates boost, ballistic and reentry phases to engage a stationary target. Targeting an object 30 miles above a launch site requires totally rewriting the software and probably modifying the hardware. It's a novel concept, and all this requires many months, if not years, of work, including test flights.

That's good news for me.
Thank you!

Originally Posted by jrmonroe

This is definitely not a matter of simply punching in new target coordinates. ICBMs have dedicated software that coordinates boost, ballistic and reentry phases to engage a stationary target. Targeting an object 30 miles above a launch site requires totally rewriting the software and probably modifying the hardware. It's a novel concept, and all this requires many months, if not years, of work, including test flights.

Hmm, I'm not so sure about that. It seems like it would be relatively easy to shoot an ICBM at something 30 miles up, even if the ICBM wasn't built for it. Just launch it on a trajectory that will bring it very close to the target (presumably you would do this by telling the guidance computer to hit some specific spot elsewhere on Earth, since the whole thing is being cobbled together on a moment's notice). They you just cause the warhead to detonate at the right time. Not knowing anything about nuclear warhead detonation procedures I don't know exactly how this would be done, but it doesn't seem like it would take a team of warhead-making engineers too long to modify a warhead to detonate when it receives a radio signal or something. Presumably people on the ground would track the missile's path and hit the "detonate" button when it was passing close to the alien ship.

Okay, so we would need software to predict the flight path based on an aimpoint and to create an aimpoint that would result in the flight path intersecting the alien spaceship. Another alternative method would simply target the spaceship and let the missile fly up and then back down again. Either way, if the spaceship is moving, we’d need real-time data about the position of the spaceship so the software would update its trajectory.

Originally Posted by jrmonroe

Okay, so we would need software to predict the flight path based on an aimpoint and to create an aimpoint that would result in the flight path intersecting the alien spaceship. Another alternative method would simply target the spaceship and let the missile fly up and then back down again. Either way, if the spaceship is moving, we’d need real-time data about the position of the spaceship so the software would update its trajectory.

If they made it this far, they'd probably detect the ballistic missile and just change their elevation or azimuth of flight.

Martian Bubba.
"Hey look they're launching another one at us."
(the crew chuckles as the pilot hit the uber throttle and ascends another 10km.)
"Wee!"

Originally Posted by Lynx_Fox

If they made it this far, they'd probably detect the ballistic missile and just change their elevation or azimuth of flight.

If the missile is launched from the other side of the world, they might not notice it as it coasted toward them on an unpowered ballistic trajectory. I guess it would all depend on how hard they were looking for it. Surely their race will have technology capable of detecting such a thing, but that doesn't necessarily mean that they'll be actively looking for it.

as to whether or not they'll be actively looking for it:

there is an almost statistically insignifigant chance that when they show up there won't be some form of war going on here on earth. and any alien race intellengent enough to build a spaceship that can make it to earth and hover in our atmosphere is probably going to check out our arsenal if it sees that we like war(which, as a species we do).

and besides, i'm of the opinion that hawking is correct in his prediction of alien species:

"If aliens visit us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans"

Originally Posted by Scifor Refugee

Originally Posted by Lynx_Fox

If they made it this far, they'd probably detect the ballistic missile and just change their elevation or azimuth of flight.

If the missile is launched from the other side of the world, they might not notice it as it coasted toward them on an unpowered ballistic trajectory. I guess it would all depend on how hard they were looking for it. Surely their race will have technology capable of detecting such a thing, but that doesn't necessarily mean that they'll be actively looking for it.

That would also assume they hadn't changed their flight path in hours. Even our planes don't use such predictable travels.

Originally Posted by Lynx_Fox

That would also assume they hadn't changed their flight path in hours. Even our planes don't use such predictable travels.

In the scenario given in the thread's opening post, the ship is simply hovering...