Explanation:
Fifty years ago
(on January 31, 1958)
the
First Explorer, was
launched into Earth orbit
by the Army Ballistic Missile Agency.
Inaugurating the era of space exploration for the United States,
Explorer I
was a thirty pound satellite that
carried instruments to measure temperatures,
and micrometeorite impacts, along with an experiment designed by
James A.
Van Allen to measure
the density of electrons and ions in space.
The measurements made by Van Allen's experiment led to an unexpected and
startling
discovery -- an earth-encircling belt of high energy electrons
and ions trapped in the
magnetosphere
now known as the
Van
Allen Radiation Belt.
Explorer I ceased transmitting on February 28, 1958, but
remained in orbit until March of 1970.
Pioneering space scientist
James Van Allen died on August 9th,
2006 at the age of 91.
