What was the first communications satellite launched by the U.S. in 1958, and what did it broadcast?

Answer

SCORE, broadcasting a pre-recorded Christmas message from President Eisenhower.

The launch of the U.S. communications satellite SCORE in 1958 was a major demonstration of capability, notable for broadcasting a pre-recorded Christmas message from President Eisenhower.

What was the first communications satellite launched by the U.S. in 1958, and what did it broadcast?
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