The first artificial satellite of Earth was placed in orbit almost 40 years ago. That event, in October 1957, had great political and technological significance. Almost overnight, thoughtful people began to discuss the possible uses of Earth satellites. Two great applications of space technology have emerged since then. Communication satellites in synchronous orbit now play a prominent role in our lives. They complement terrestrial links and offer communication services not previously available. Equally profound has been the development of a worldwide navigation service based on the constellation of Global Positioning System satellites.

Topics
Geographic information systems, Space instruments, Space technology, Communication satellites
1.
K. C. Ruffner, ed., Corona, America's First Satellite Program, Center for the Study of Intelligence, CIA, Washington, DC (1995).
2.
R. C.
Hall
,
Prologue, Quarterly of the National Archives
27
,
59
(
1995
).
3.
J. E. Lipp, R. M. Salter, Project Feed Back Summary Report, contract no. AF 33(038)‐6413, Rand Corporation, Santa Monica, Calif. (1954).
4.
R. A.
MacDonald
,
Photogrammetric Engineering and Remote Sensing
61
,
689
(
1995
).
5.
F. D. Smith, Optics and Photonics News, October 1995, p. 34.
6.
R. E.
Hufnagel
,
N. R.
Stanley
,
J. Optical Soc. Am.
54
,
52
(
1964
).
Crossref
Search ADS
 
7.
D. L.
Fried
,
J. Optical Soc. Am.
56
,
1380
(
1966
).
Crossref
Search ADS
 
8.
A. D. Wheelon, in Space Technology, H. Seifert, ed., Wiley, New York (1959).
9.
A. D.
Wheelon
, “
Antisatellite Weapons and Space Warfare
,”
Ann. New York Acad. Sci.
489
,
38
(
1986
).
Google Scholar
Crossref
Search ADS
 
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© 1997 American Institute of Physics.
1997
American Institute of Physics
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