COLLECTION NAME:
NASA Astronomy Picture of the Day Collection
Record
Title:
The First Explorer
Explanation:
Fifty years ago (on January 31, 1958) the First Explorer [ http://www.nasa.gov… ], was launched into Earth orbit [ http://www.redstone… welcome.html ] by the Army Ballistic Missile Agency. Inaugurating the era of space exploration for the United States, Explorer I [ http://history.nasa… ] was a thirty pound satellite that carried instruments to measure temperatures, and micrometeorite impacts, along with an experiment designed by James A. Van Allen [ http://history.nasa… ] 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 [ http://www.phy6.org… ] -- an earth-encircling belt of high energy electrons and ions trapped in the magnetosphere [ http://www.phy6.org… ] now known as the Van Allen Radiation Belt [ http://www.phy6.org… ]. Explorer I ceased transmitting on February 28, 1958, but remained in orbit until March of 1970. Pioneering space scientist James Van Allen [ http://www.nasa.gov… james_van_allen.html ] died on August 9th, 2006 at the age of 91.
Credit and Copyright:
Courtesy of Marshall Space Flight Center [ http://mix.msfc.nas… ], NASA [ http://www.nasa.gov… ]
facet_when:
1970
facet_where:
Goddard Space Flight Center (GSFC)
facet_what:
Earth
facet_when_year:
1958
UID:
SPD-APOD-ap080201
