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I noticed four(?) towers around the SpaceX launch pad during yesterday's aborted launch

enter image description here

img credit NBC News

What are the towers used for? Tracking? Radio communications?

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Some clearer photographs are available on the Wikipedia page on Cape Canaveral Air Force Station Space Launch Complex 40. ;) –  TildalWave Nov 29 '13 at 20:42

2 Answers 2

up vote 22 down vote accepted

They are used to redirect lightning in the immediate area. This essentially creates a faraday cage, shielding the rocket from being fried by lightning. You can see how high the towers reach, high enough to ensure there is no risk of lightning hitting the craft. Also, since this is a mobile launch platform, it would be safe to assume that the towers have some sort of motorised mechanism to adjust their height, allowing for a wider range of launches.

TL;DR: They're lightning rods.

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The big top rods are insulators. Such cages are grounded through wires sloping out to ground points several tens of meters away. Also the ground points are connected to each other by a potential equalization loop. The metal lattices of the towers are grounded too, and also connected to the loop - but they are insulated from the tips, so in a strike they do not act as conductors. There was one such insulator on the top of the Shuttle launch tower. It was a spun fiber in polymer matrix structure, ad the time the biggest such cylinder in the world. The tip was connected to three ground points.

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Welcome to Space Exploration Stack Exchange! It is clear from your answer that you are knowledgeable about the subject, but for the benefit of others we have a standard here that we try to include the source of our information in our posts. The source does not have to be physical text or a web link, but even if you are an expert in the field and this is from off the top of your head a little bit of an explanation helps the rest of us understand the context of your information and accurately judge its worth. Thanks! Feel free to join us in chat when you reach 20 reputation points for more help. –  called2voyage Dec 2 '13 at 16:40
The user who posted the accepted answer (Mark Adler) is well known around here, and his qualification is publicly available (see Mark Adler on Wikipedia), so no further explanation was needed about his source of the information. –  called2voyage Dec 2 '13 at 16:43
@called2voyage: I didn't realize that is the same Mark Adler from zip! In fact, it has been nagging me that the name seemed familiar. Thanks for mentioning that! –  dotancohen Dec 6 '13 at 9:37
Saying they're insulators doesn't really answer what they're used for so I'm surprised this answer has so many upvotes. –  NickG Feb 10 at 10:29

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