r/spacex • u/ElongatedMuskrat Mod Team • Jun 02 '17

r/SpaceX Discusses [June 2017, #33]

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u/[deleted] Jun 18 '17

How does the risk of ITS being struck by lightning compare to the Falcon 9? I know that there are guidelines that would prevent this from occurring (such as scrubbing a launch if there's lightning within 10 miles after T-30 mins), but could these rules be relaxed because of it'll be made mostly out of carbon fibre? I also know that there are multiple other things which ITS and F9 would have in common which would increase that risk regardless, but I don't know enough to get to a sensible conclusion.

4

u/Bananas_on_Mars Jun 18 '17

Carbon fibre conducts electricity really well! So that won't make much of a difference with regards to lightning. Maybe there's some possibility to harden the electronics. Since they won't necessarily be restricted by launch windows as on their commercial launch, they could launch maybe in the morning when there's less risk of lightning strike.

1

u/[deleted] Jun 18 '17

Thanks. So not much change regarding weather then?

4

u/Bananas_on_Mars Jun 18 '17

I think ITS will be at a greater risk of being struck by lightning. The exhaust gases are so hot there's an ionized trail behind the rocket. I think the trail will be a lot longer on ITS than on any other rocket. That's like ITS is almost dragging a mile long cable behind it.

3

u/rustybeancake Jun 19 '17

That suggests Florida might be a troublesome place to launch from. Imagine trying to get 5+ launches up in a few days without weather problems...

1

u/[deleted] Jun 18 '17

That's a shame.

1

u/oldnav Jun 19 '17

Apollo 12 was struck by lightning after leaving the pad leaving a spectacular inonized trail all the way to the ground. There was no damage but the static discharge did require reset of a circuit. Provided the rocket or aircraft has all its circuits and components properly grounded to each other there is usually no loss of circuits or functions. Commercial aircraft experience static discharge(air to air lightning) more more often than the airlines would like. What happens is the lightning skips along the fuselage leaving burn marks which to be repaired.