Profile of ISTP

ISTP

News

December 1997

Profile of a Sun-Earth
Observatory: ISTP

istp2'>
</td>
</tr></ul>
</table>

<dl>
<dt><font size=4 color=#ff3333><i><b>What?</b></i></font><br>
<dd>The International Solar-Terrestrial Physics (ISTP) program is a
comprehensive effort to observe and understand our star and its
effects
on
our environment. An armada of space- and ground-based
observatories
probe
the Sun, the Earth, and the space between them from many angles and
in
many
different ways...most of them invisible to the human eye.<br><br>

<dt><font size=4 color=#ff3333><i><b>Why?</b></i></font><br>
<dd>Events on the Sun can trigger changes in Earth's environment,
particularly in the regions of the atmosphere known as the
ionosphere
and the
magnetosphere. Like the wind here on Earth, the solar wind blows
soft
and
hard, sometimes leading to magnetic storms in the atmosphere. Such
storms
can interfere with radio, television, and telephone signals, upset
the
navigation systems of ships and airplanes, and cause blackouts.
Also,
Sun-induced storms can damage satellites and spacecraft or force
them to
re-enter the atmosphere prematurely. By closely observing the Sun
and
the
energy and material it blows at Earth, scientists may someday be
able to
anticipate changes in Earth's environment. Aside from disturbing
our
electronic tools and toys, the Sun and its wind--the solar
wind--seem to
play
a role in long-term climate changes on Earth. And finally, since
our
solar
system is probably typical of other single-star systems in the
universe,
what
scientists learn about the Sun-Earth connection could lead to a
better
understanding of other solar systems.<br><br>

<dt><font size=4 color=#ff3333><i><b>Who?</b></i></font><br>

<dd>
<table border=0>
<caption>ISTP includes spacecraft launched by:</caption>

<ul>
<tr>
<td align=center>
<a href=http://www.nasa.gov/ target=

Spacecraft and significant computer and radar facilities are provided by: Max Planck Institute, NOAA, LANL, and the Air Force. Canadian Space Agency, British Antarctic Survey, U.S. National Science Foundation, and Johns Hopkins Applied Physics Laboratory.

Where and How?

The spacecraft of ISTP are placed in orbits that allow physicists to observe the key regions of Earth's space, or "geospace." Those regions include the Sun's surface and atmosphere, the solar wind, Earth's magnetosphere, from the bow shock to the auroral regions to the magnetic tail. Orbiting as far as one million miles from Earth and as close as a few hundred, the spacecraft of ISTP make coordinated, simultaneous observations of the Sun and geospace over extended periods of time.

With such observations, scientists are increasing our knowledge of:

The structure and dynamics of the Sun;
The origin of the solar wind;
The composition and character of the solar wind;
The flow of energy between Sun and Earth; and
The cause-effect relationship between events on the Sun and their impact on Earth.

When?

ISTP was conceived in the 1970s, planned in the 1980s, and launched in the 1990s. The first spacecraft, Geotail, was launched in 1992, and the most recent, Polar, went up in 1996. Each of the missions of ISTP is scheduled to continue through 1998, and scientists and engineers are now making plans to extend their mission through the next solar maximum in 2000-2002.

Comments, Questions, Suggestions Webmaster
Author: Mike Carlowicz
Official NASA Contact: ISTP-Project
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