Donald L. Savage Headquarters, Washington, D.C. August 1, 1994 (Phone: 202/358-1547) Keith Kohler Wallops Flight Facility, Wallops Island, Va. (Phone: 804/824-1579) RELEASE: 94-126 NASA Sounding Rocket Campaign to Study Ionosphere with Brazil ASA will conduct with Brazilian space agencies a joint campaign to study the Earth's space environment over the magnetic equator from August 15 through October 20, 1994. During the campaign, the NASA Goddard Space Flight Center's (GSFC) Wallops Flight Facility (WFF), Wallops Island, Va., will launch 33 rockets from the Centro de Lancamento de Alcantara launch range in the northeastern state of Maranhao, Brazil. The campaign will help scientists better understand the unique properties of the Earth's ionosphere at the equator and is an integral part of the International Equatorial Electrojet Year. The project has been named the Guara Campaign after a beautiful species of bird native to the equatorial region of Brazil. The ionosphere interests scientists because it acts like a mirror, reflecting high frequency radio waves, carrying currents that affect power systems on the ground and disturbing satellite transmissions that must pass through it. According to the NASA campaign scientist, Dr. Robert Pfaff Jr., from GSFC in Greenbelt, Md., the Earth's magnetic field lines, which are parallel to the Earth's surface at the equator, affect the physics and electrodynamics of the equatorial ionosphere. This creates a variety of natural phenomena, including spectacular "eruptions" and turbulence in space, as well as intense currents or "electrojets." The location where the field lines are exactly horizontal to the Earth is known as the magnetic equator. The Alcantara launch range is within one degree of the magnetic equator. The sounding rocket campaign will investigate the electrodynamics and irregularities in the ionosphere and mesosphere along the magnetic equator and will study their relationship with the neutral atmosphere and winds. The sounding rocket experiments primarily will measure electric fields, currents, electron densities, neutral winds and ionospheric instabilities. Suborbital sounding rockets provide the only means possible to take direct measurements in some regions of the Earth's atmosphere. The sounding rocket experiments during the Brazilian campaign require simultaneous measurements taken by ground-based scientific instruments, including backscatter radar, magnetometers and ionosondes. These instruments will be provided by scientists from the Brazilian Space Agency, Instituto Nacional de Pesquisas Espaciais (INPE). More than 50 U.S. and Brazilian scientists will participate in the Guara campaign, supported by teams of approximately 300 engineers, technicians and staff. NASA plans to fly a Brazilian science experiment as part of one of the payloads. The Brazilian scientific participation is coordinated by the INPE. Both sides will share the data from the rocket-borne and ground-based instruments. The Commission for Space Activities of the Federative Republic of Brazil (COBAE) will provide launch support services to NASA. The rockets are divided among four experimental groups. Between August 15 and 27, four Nike-Orion sounding rockets and 20 Viper 3A small meteorological rockets will be launched. The payloads will explore the interactions between small-scale turbulence and large-scale tidal motions and waves in the middle atmosphere at the magnetic equator. The Principal Investigator (PI) for the Nike-Orion experiments is Dr. Richard Goldberg from GSFC, and the PI for the Viper rockets is Frank Schmidlin from the WFF. From September 1 through 20, four Black Brant VC sounding rockets will be launched during daytime, sunset and nighttime conditions carrying experiments to study the equatorial electrojet. The electrojet is an intense current of electrons that forms a corridor about one degree wide, encircling the Earth precisely along the magnetic equator at about 60 to 70 miles (96 to 112 kilometers) altitude. The payloads will measure, for the first time, the polarization electric fields that drive the electrojet current, as well as the current density itself. The PI is Dr. Robert Pfaff. Four Nike-Tomahawk sounding rockets will be launched between September 21 and October 6. These experiments include a series of barium and trimethyl aluminum chemical releases near 127 miles (205 kilometers) altitude to study the winds and associated electric fields in the ionosphere at sunset. The chemical trails are studied using photographs taken on the ground as well as on board a NASA airplane. The PI is Dr. Miguel Larsen from Clemson University in South Carolina. The final launch will be a Black Brant X sounding rocket carrying experiments to measure the density and electric field turbulence associated with large depletions (or bubbles) that occur in the ionosphere at night along the Earth's magnetic equator. This payload includes the Brazilian experiment to measure plasma density. The PI is Dr. Jim LaBelle from Dartmouth College, Hanover, N.H. NASA has conducted nine previous equatorial sounding rocket campaigns since 1964 from South America, Asia, Africa and the southern Pacific Ocean. These campaigns have included launching 97 suborbital rockets. The WFF manages the NASA Sounding Rocket Program for the Office of Space Science, NASA Headquarters, Washington, D.C. The program conducts an average of 30 missions annually from sites worldwide. - end -