# What are the rectangular wires around Atlas V launch site?

You can see those wires spanning between four towers directly around the rocket in the following screenshot (taken from this video). I assume they are some kind of antenna or for some kind of measurement. I have also seen this setup in at other rocket launches. Can anyone tell what it is there for?

• Like the towers around: Lightning rods. – asdfex Mar 25 '16 at 17:34
• Is there a reason some sites do have those and others do not? – flawr Mar 25 '16 at 17:34
• Mainly geometrical reasons - the rocket must not be the highest point within some area. If the towers are tall enough or close enough the wires are not needed. Same if the weather is reasonably stable at the launch side. – asdfex Mar 25 '16 at 17:37
• If these were antennas, the frequencies involved would be in the MF or low HF range (up to a few MHz). Outside of specialty applications, that frequency range isn't in common use any longer. To a first order approximation, if these were antennas they would probably be half-wavelength or one-wavelength loops. $\lambda = \frac{c}{f}$ and you do the math if you think that's plausible. :) – a CVn Mar 29 '16 at 15:31
• @MichaelKjörling That is actually a quite nice way of looking at it and totally makes sense, thank you=) – flawr Mar 29 '16 at 17:36

These wires are part of the lightning protection. As a rocket contains flammable [citation needed] components as well as sensitive electronics, it needs to be protected from lightning strikes. The main protective measure are the huge towers surrounding the rocket. If theses towers are high enough and closely located around the rocket they might provide sufficient protection. In your picture an additional grid of wires is used to better shield the central part of the start complex.

To determine whether protection is sufficient, one uses a geometry based method: If a ball of a given size (blue, typically 20 to 60 meter radius, depending on how much protection is needed) can not reach the object, then it is safe. In the drawing, the two black masts are sufficient to protect the green rocket but not tall enough to protect the red one. In the later case the towers need to be taller, closer together or an additional mesh is needed. Note that protection from sideways is not needed as much as protection from top.

• So where's the citation for the statement that rockets contain electronics? :-) – a CVn Mar 29 '16 at 15:32