The First Explorer
Credit & Copyright: ABMA,
Courtesy
JPL
Explanation:
The first US spacecraft was
Explorer 1.
The
cylindrical 30 pound satellite
was launched (above) as the fourth stage of a
Jupiter-C rocket (a modified
US Army Redstone
ballistic missile) and achieved orbit on January 31, 1958.
Explorer I carried instrumentation to measure internal and external
temperatures, micrometeorite impacts,
and 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 Belt.
Explorer I ceased
transmitting on February 28 of that year but
remained in orbit until March of 1970.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
