NASA will conduct a sounding rocket campaign in the South Pacific during August
and September to better understand the Earth’s ionosphere in the equatorial
region. The EQUatorial Ionospheric Study (EQUIS II) project is designed to study
disturbances in the ionosphere created by interactions between the Sun and the
Earth’s magnetic field.
NASA Goddard Space Flight Center’s Wallops Flight Facility, Wallops Island, Va.,
will launch 14 suborbital sounding rockets from a launch complex located on the
island of Roi-Namur, Kwajalein Atoll, Republic of the Marshall Islands. EQUIS II
is similar to studies conducted from Roi-Namur during the EQUIS project in 1990.
"NASA and a team of scientists from several universities will launch the rockets
to make measurements of electrical and turbulent layers that occur in the
ionosphere," said Miguel Larsen, campaign scientist from Clemson University,
S.C. "People tend to think that space is a quiet place with relatively little
activity. Over the years, we have come to realize that this is not true."
Four separate scientific missions will investigate nighttime plasma structures,
electrodynamics, and mesospheric scattering processes. Six rockets will carry
experiments containing Trimethyl Aluminum (TMA), a tracer of atmospheric
motions, that when released will form milky, white clouds in the nighttime sky.
Two rockets will carry instrumentation as well as TMA and six rockets will carry
only scientific instruments.
The TMA will be released over the Pacific Ocean at altitudes from 50 miles (80
kilometers) to 125 miles (200 kilometers) and will produce light that can be
tracked visually and with special camera equipment located at optical sites on
the islands of
Roi-Namur, Likiep, Rongelap, and Bikini. The clouds form within seconds after
the TMA release and are visible for 10 to 30 minutes. The tracer, which breaks
down into harmless components of aluminum oxide, carbon dioxide and water vapor,
will show the location of shears and turbulence responsible for electrical
disturbances in the upper atmosphere.
"Winds in the ionosphere create disturbances, just as winds on Earth impact our
weather. Space weather in turn can affect communication and electrical systems
such as Global Positioning Systems (GPS)," said Dr. David Hysell, Principal
Investigator, from Cornell University, Ithaca, N.Y. "Communication and
navigation systems, particularly those that involve ground to satellite links
either experience errors or they fail altogether when this phenomenon called
Spread-F occurs."
The time and day of launch depends on two major factors: clear nighttime skies
are required at two of the four special camera sites and a layer of ionized
particles must form in the upper layers of the ionosphere and begin to descend.
The launches will include eight Terrier-Improved Orions, two Terrier-Malemutes,
two Nike-Black Brants and two Black Brant rockets.
Dr. David Hysell, Cornell University, is the principal investigator for
experiments that will investigate the electrodynamics of the nighttime
equatorial ionosphere and the bearing this has on the thin radar scattering
layers that form within the upper atmosphere.
Dr. Lynette Gelinas, Cornell University, will use TMA releases to characterize
the neutral winds associated with the ionospheric gravity wave disturbances
using ground-based imagers and wind profile measurements.
Dr. Gerald Lemacher, Clemson University, will use instrumented payloads to
measure neutral density, temperature fluctuations, electron, ion and particle
environment parameters in order to understand the unusually strong radar
scattering often observed in the equatorial mesosphere.
Dr. Robert Pfaff, NASA Goddard Space Flight Center, Greenbelt, Md., will conduct
an investigation of plasma irregularity structure in the nighttime equatorial
ionosphere and the bearing this has on strong radio wave scattering layers that
form in this region.
The EQUIS II project is being conducted under the Sounding Rocket Program, which
is managed at Wallops for NASA’s Office of Science, Washington, D.C.
Approximately 125 people from NASA Wallops Flight Facility and the scientific
community will be involved in the campaign.
Further information and updates on the EQUIS II project, including a schedule of
the rocket launches, is available at:
http://www.wff.nasa.gov/~code810/
