By the way Mr Musk,

 

to ensure safety.

 

Several turbines can have a separate power source,

in case one fails.

 

Or some combination that can minimize sudden dysfunction.

 

You know how aircrafts still float if one engine fails

same concept.

 

Then combined with the auto parachutes,

energy level checks and component failure sensors....

 

I don't think there's much risk of failure.

 

Unless, someone gets struck by thunder.

 

Why also, fortified plastic is a better option

as its shell.