Complex sentence: The man who United States President Eisenhower was not surprised by "Sputnik", having been forewarned of the R-7s capabilities by information derived from U2 spy plane overflight photos as well as signals and telemetry intercepts.
Split into simpler sentences: The man who United States President Eisenhower was not surprised by "Sputnik." He had been forewarned of the R-7s capabilities by information derived from U2 spy plane overflight photos as well as signals and telemetry intercepts.