|Mission type||Earth science|
|Mission duration||1,426 days|
|Manufacturer||Langley Research Center|
|Launch mass||8.6 kg (19 lb)|
|Start of mission|
|Launch date||21 November 1964, 17:09:39UTC|
|Launch site||Vandenberg SLC-5|
|End of mission|
|Decay date||18 October 1968|
|Perigee altitude||525 km (326 mi)|
|Apogee altitude||2,498 km (1,552 mi)|
|Epoch||21 November 1964|
|Nonsystematic Changes of Air Density|
Systematic Changes of Air Density
Explorer 24 (also called AD-B and S-56C) was a U.S. satellite designed for atmospheric studies. Explorer 24 was launched on 21 November 1964 from Vandenberg Air Force Base, Lompoc, California, with a Scout rocket. Explorer 24 was launched along with its successor satellite, Explorer 25.
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. To facilitate ground tracking, the satellite carried a 136 MHz tracking beacon.
The satellite reentered the earth's atmosphere on October 18, 1968.
Explorer 24 helped determine the variation in density between the day and night of the Earth and gave rise to studies on the zone winds in the exosphere, at an altitude of between 450 kilometres (280 mi) and 620 kilometres (390 mi).