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Delta-V of an ICBM


Skyler4856

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Kim Jong Un, is that you? Now what did we tell you about trying to get information for your ballistic missile program from the Kerbal Space Program forums? That's right, it's a bad idea. Now if you want to make long range ballistic missiles you'll just have to do it yourself.

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Depends on range. For maximum range, you need an almost orbital velocity. So that's about 7.8km/s to reach ballistic trajectory, plus about 1.5km/s for aerodynamic losses, which puts you at about 9.3km/s.

However, far from all ICBMs are capable of targeting a point clear on the opposite side of the world. A rocket capable of about 7km/s can already put a projectile on a high ballistic trajectory with a target located over 6,500km away, which is definitely intercontinental range. So if you are looking for a minimum, it's about that.

Interesting thing to note. While long range missile will have a shallow trajectory, with apogee just high enough above the atmosphere to avoid loosing too much speed on the way, a "short range" ICBM will have a trajectory that's much closer to what you picture a ballistic trajectory to be, with apogee well above 1,000km.

Edited by K^2
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Depends on what you put on it.

Nuclear missile Dv: Absolutely no clue, nor do I want or need to know.

ICBM converted into a launch vehicle: enough to get to the moon.

Unless you are talking about the warp drive-capable Phoenix from Star Trek, I don't think any ICBM has the capacity to go to the Moon.

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  • 1 year later...
On 1/27/2014 at 8:51 PM, rdfox said:

Just go to www.astronautix.com and look up any ICBM of your choice. It'll have full stats, including thrust of each stage, TWR on each stage, and total delta-V, just like any other launch vehicle.

Bit of necromancy here:  That site has no delta-v numbers on any ICBM I looked up.  (I was interested in how far out an ICBM could go.)

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1 hour ago, Loren Pechtel said:

Bit of necromancy here:  That site has no delta-v numbers on any ICBM I looked up.  (I was interested in how far out an ICBM could go.)

You could do the calculations, it has the data to allow you to do that.

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Total dv of say, a Minuteman III? I'd suspect upwards of 10km/s.

Remember, you've gotta have enough on the booster to put the bus almost into orbit, and then enough on the bus to do a plane change and multiple deorbit burns to set the independent trajectories of the RVs.

The upside is that you can go for high TWR, since there's no fleshbags aboard to complain about G forces.

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1 hour ago, tater said:

Why would they do a plane change with the MIRV bus, when they could simply target all warheads aboard in the same rough plane? Seems needlessly complex.

Probably for more precise plane changes, to be as damaging as possible.

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Yeah, but it doesn't need much dv for small plane changes to scatter RVs over a few hundred km wide swath. The discussion was about dv requirements, I'm thinking substantial plane changes would be a bad design choice when you have hundreds of missiles to use so you have no need for large plane changes after boost (you'd incline the launch for MIRVs to a particular region, instead)

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7 minutes ago, tater said:

Yeah, but it doesn't need much dv for small plane changes to scatter RVs over a few hundred km wide swath. The discussion was about dv requirements, I'm thinking substantial plane changes would be a bad design choice when you have hundreds of missiles to use so you have no need for large plane changes after boost (you'd incline the launch for MIRVs to a particular region, instead)

I'm thinking it would be for precision adjustments- they are used as post-boost stages, after all.

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1 hour ago, tater said:

Why would they do a plane change with the MIRV bus, when they could simply target all warheads aboard in the same rough plane? Seems needlessly complex.

Likely to alter trajectory at midcourse from the boost trajectory predicted by observers at launch, think FOBS

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I get what you mean, I'm assuming they do small changes to facilitate hitting diverse targets. My point is that the buss stage doesn't have substantial dv, as they are making (as you say) only small changes for a given bus. 

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13 hours ago, tater said:

I get what you mean, I'm assuming they do small changes to facilitate hitting diverse targets. My point is that the buss stage doesn't have substantial dv, as they are making (as you say) only small changes for a given bus. 

There's more to it. To conceal the destination, one would launch misaligned with the target, and realign at apoapsis, thus giving minimal warning of destination

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3 minutes ago, tater said:

Well, assuming missile defense systems are deployed that don't actually exist. It has not yet actually been required. Countermeasures for SDI were always far cheaper than the SDI systems envisioned.

Nike Sprint wasn't SDI

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No, those terminal defense systems were actually deployed :) Still, that system was not really a complete defense, and the boost data didn't matter, they'd only target RVs heading into their defense zone anyway, so plane changes wouldn't matter, they picked targets that were already inbound to their defense zone.

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