Actually, Lockheed was probably doing tests on nitrogen, not helium. They use nitrogen in the tires of planes because it is an inert gas and will not expand when changes in temperature occur.
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Yeah, I believe it was Nitrogen. Now I will say that even though a lot of people say that filling your tires with nitrogen does not really have any effects, I disagree. I have done nitrogen fills in my tires and can definitely tell a difference with the nitrogen.