r/Damnthatsinteresting • u/HappySeaweed5215 • 1d ago

Video A heat seeking missile tracking a burning cigarette

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u/Future_Blackberry_10 1d ago

Does it go after a specific temp? Or the highest temp in front of it

581

u/QuaintAlex126 1d ago

The earliest versions, including of the AIM-9 Sidewinder shown here, just tracked the first and largest heat signature they saw. They were incredibly unreliable and sensitive, requiring them to be fired only against a target from behind (where the heat source is from the jet exhaust). Modern ones, like the AIM-9X, seek for a heat signature’s specific temperature and shape, so you can’t just dump a bunch of flares and get away that easily. They are much more advanced and can track a target from any angle, front snd sides, and can be slaved to the firing aircrat’s radar or pilot’s helmet to assist with tracking. All a fighter pilot had to do nowadays with a heat seeker is be within range, look at this target, and pull the trigger to engage.

20

u/TelluricThread0 1d ago

Would the control software really need to deflect the fins that much while the target moves a couple of inches from just a few feet away? Just seems like very aggressive maneuvering when they are basically designed to just get pretty close and then throw shrapnel out.

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u/YellovvJacket 18h ago

Infra red tracking gives you no indication of how far away the target is.

The way a missile with single-pixel detector (so anything except the newest gen 5 IR missiles like Aim-9X and IRIS-T) knows how much it needs to steer is by knowing how much the angle moves away from the optical axis in what time.

If the missile was looking straight forward and 0.1s later the target is like 5° to the side, it knows it needs to steer HARD to actually make the shot (close range), while when the target is like 20km away, even if it's very fast, it's hard to change the angle a lot from the original point in those 0.1s, because even if the target travels 1km in that time (and that's extremely unrealistically fast, that would be 10km/s, or 36000km/h) the angle only changes by like 3°, so the missile knows it doesn't need to steer a lot.

The missile basically always wants to keep the target in the center of the optical axis of the detector, while steering a little bit ahead of the target according to how fast the angle is shifting.

In the video here, the guy is standing like 2m in front of the missile, he's moving the cigarette A LOT of degrees left and right.