A test inflation of the Echo II satellite. Note the size of the car and people beneath the balloon.
Image: NASA.

On this date in 1964, NASA launched Echo 2, a passive communications satellite. Effectively a simple aluminum-mylar balloon, Echo 2, like its predecessor Echo 1, acted as a simple reflector, allowing other weather and communications satellites to bounce their signals to various points on the globe. A concise summary of the Echo program may be found here.