Template:Are You Sure/January 20

• ... that Project SCORE (Signal Communications by Orbiting Relay Equipment) was the world’s first communications satellite, as well as the first successful use of the Atlas rocket as a launch vehicle?
• ... that electrical engineer Elisha Gray invented a harmonic telegraph which transmitted multiple tones simultaneously, and that each tone was controlled by a separate telegraph key?
• ... that physicist David Brewster discovered the photoelastic effect while studying double refraction by compression, inaugurating the field of optical mineralogy?