2. SPACE WEATHER DEFINED (TELECOMMUNICATION SYSTEM VULNERABILITIES TO SPACE-WEATHER EVENTS
John Michael Goodman1
Radio Propagation Services, Inc.
Alexandria, Virginia)
What is space weather? The US Department of Defense, in its implementation plan (OSD,
2000), indicates, “Space weather refers to adverse conditions on the sun, the solar wind, and in the
earth’s magnetosphere, the ionosphere, and the thermosphere.” Indeed this definition portrays those
aspects of space weather that are generally of most concern, namely the more pathological elements.
But space weather, and ionospheric weather, in particular, can be turbulent or benign. All aspects of
space weather should be included in the definition. Indeed, from a telecommunications perspective, it
can be safely stated that quiet conditions are not always good and disturbed conditions are not always
bad. The National Space Weather Program (NSWP, 1995) has defined space weather as
representing “conditions on the sun and in the solar wind, magnetosphere, ionosphere, and
thermosphere that can influence the performance and reliability of space-borne and ground-based
technological systems.” This definition is more appropriate. On the NOAA/SEC web site, it is indicated
“Space Weather describes the conditions in space that effect Earth and its technological systems.” It goes on to say, “Space Weather is a consequence of the behavior of the sun, the nature of Earth’s
magnetic field and atmosphere, and our location in the solar system”. We like this definition as well.
