The Dynamics Explorer A and B satellites designed to explore the interactive processes occuring between the magnetosphere and Earth's ionosphere, upper atmosphere, and plasmasphere are described. Effects of these interactions, satellite orbits, data collecting antennas, solar power systems, axes, configurations, and Earth based command, control and data display systems are mentioned

Redmond, C.

English

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IWNSANews
National Aeronautics and
Space Administration
Washington, D.C. 20546
AC 202 755-8370
For Release:
Charles Redmond
Headquarters, Washington, D.C. IMMEDIATE
(Phone: 202/755-3680)
James Lacy
Goddard Space Flight Center, Greenbelt, Md.
(Phone: 301/344-5565)
RELEASE NO: 81-35
DYNAMICS EXPLORER TWIN SPACECRAFT UNDER EVALUATION TESTS
Two spacecraft that will ride piggy-back into orbit next
July are currently undergoing rigorous prelaunch testing at the
Goddard Space Flight Center, Greenbelt, Md.
Called Dynamics Explorer (DE) -A and -B, the twin satellites
are scheduled to be stacked together and placed into coplanar
polar orbits by a Delta 3913 launch vehicle from the Western
Space and Missile Center, Lompoc, Calif., on July 31.
Their mission will be to explore the boundary region between
Earth and space that affects the atmosphere, auroral displays,
radio transmissions and perhaps climate and_we.a.ther_
 N
(HASA-8ews-Release-81-35) DYNAMICS*EXPLORER 881-21104
THIN (SPACECRAFT JUNDER EVALUATION TESTS
(National Aeronautics and Space
Administration) 4 p CSCL 22B Unclas
00/15__19836
March 13, 1981
„ -.mo ire-
https://ntrs.nasa.gov/search.jsp?R=19810012575 2020-03-21T13:28:50+00:00Z
-2-
Solar radiation and the solar wind have a dynamic impact on
the near Earth environment, result of which affect the state of
the atmosphere, ionosphere, magnetosphere and the more familiar
phenomena — weather, auroral displays and radio disturbances.
Prior spacecraft such as the Atmospheric Explorers have pro-
vided new information on solar radiation upon the lower thermo-
sphere and upper atmosphere. The ISEE (International Sun-Earth
Explorer) program has provided additional new information on
interactions between the solar wind and the Earth's magnetic
/
field; however, adequate knowledge does not exist regarding
interactions between the two regions.
The Dynamic Explorer program is designed to supply such
knowledge — specifically, the strong interaction processes coup-
ling the hot, tenuous, convecting plasmas of the magnetosphere
and the cooler, denser plasmas and gases co-rotating in Earth's
ionosphere, upper atmosphere and plasmasphere.
To accomplish this, the project will provide a central data
processing and analysis system available so that each investiga-
tor on the science team can display geophysical data from all
spacecraft instruments.
In their polar, coplanar orbits, one satellite (DE-B) will
have a perigee sufficiently low (305 kilometers or 190 miles) for
neutral composition, temperature and wind measurements.
-more-
-3-
Its apogee will be sufficiently high (1,300 km or 808 mi.)
to provide a lifetime greater than one and one-half years and to
allow measurements above the interactive regions for super-
thermal ions and plasma flow measurements of the magnetospheric
field lines.
The second spacecraft (DE-A) will be placed into a highly
elliptical orbit having an apogee of 24,875 km (15,457 mi.) to
allow for global auroral imaging, wave measurements in the middle
of the magnetosphere and crossings of auroral field lines at sev-
eral Earth radii.
The DE-B (low mission) has six 3-centimeter (1.2-inch) dia-
meter flexible stem antennas 10 meters (33 feet) long, and a
single rigid boom 6 m (20 ft.) long. These external antennas will
collect data for the scientific instruments on board.
The solar cell arrays mounted on the 136-cm (53.5-in.) dia-
meter spacecraft body will supply the satellite with electrical
energy which can be delivered directly to the scientific instru-
ments or stored in nickel-cadmium batteries as required.
DE-A is spin stabilized; its pitch, or spin axis having a
spin rate of 10 rpm while the DE-B spacecraft is three axis sta-
bilized with its pitch axis controlled to continually point
towards the Earth's surface. Configurations of both spacecraft
are designed to minimize unbalancing torques created by atmos-
pheric drag encountered in space.
-more-
-4-
Tracking, command, realtime and recorded data will be pro-
vided by NASA's Space Tracking and Data Network; the NASA World-
wide Communications System* NASCOM; and the DE-Operations Control
Center at Goddard.
-end-
Note:
Photographs to illustrate this news release will be distri-
buted without charge only to media representatives in the United
States. They may be obtained by writing or phoning:
Public Affairs Audio-Visual Office
Code LFD-10/NASA Headquarters
Washington, D.C. 20546
Telephone No: 202/755-8366 Photo No: 81-H-33
81-H-34
(Index: 33, 36)


Dynamics Explorer twin spacecraft under evaluation tests

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