Explorer 24 was placed in orbit together with Explorer 25 from a single launch vehicle. Explorer 24 was identical in configuration to the previously launched balloon satellites Explorer 9 and 19. The spacecraft was 3.6 m in diameter, was built of alternating layers of aluminum foil and plastic film, and was covered uniformly with 5.1-cm white dots for thermal control. It was designed to yield atmospheric density near perigee as a function of space and time from sequential observations of the sphere's position in orbit. November 21, 1964 at 17:09 UTC · Launch Successful Scout X-4 — National Aeronautics and Space Administration, to Elliptical Orbit Space Launch Complex 5, Vandenberg SFB, CA, USA The world's 381st orbital launch attempt, and 88th of 1964. Data: Launch Library 2, The Space Devs. Image by U.S. Air Force (Department of Defense Image Use Policy) via The Space Devs.