History of Juno 1

Successful Launches

Jan 31, 1958

Explorer 1
https://en.wikipedia.org/wiki/Explorer_1

Unsuccessful Launches

Mar 5, 1958

Attempted orbit of Explorer 2. Failed because fourth stage did not ignite .
https://en.wikipedia.org/wiki/Explorer_2

Successful Launches

Mar 26, 1958

Explorer 3
https://en.wikipedia.org/wiki/Explorer_3

Successful Launches

Jul 26, 1958

Explorer 4
https://en.wikipedia.org/wiki/Explorer_4

Unsuccessful Launch

Aug 24, 1958

Explorer 5 . It failed after booster collided with second stage after separation, causing upper stage firing angle to be off .
https://en.wikipedia.org/wiki/Explorer_5

Unsuccessful Launch

Oct 23, 1958

Attempted orbit of 12 ft inflatable Beacon satellite (of Project Echo) . It failed when second stage separated prematurely from booster
https://en.wikipedia.org/wiki/Juno_I