Geophysics: Dragonflies in Space

While headlines glamorize the U.S.

Russian race to the moon, man's most useful achievements in space have come as the result of an unsung project started in 1964: the U.S. Orbiting Geophysical Observatory series. Last week the fourth OGO satellite, launched from California's Vandenberg Air Force Base on July 28, was buzzing along in polar orbit without a hitch.

Resembling giant stub-winged dragonflies, OGOs circle in polar and equatorial orbits at altitudes of 170 to 90,000 miles. So far, they have logged 500,000 hours studying near-earth environment and the sun's effects on it. OGOs have recorded cosmic rays, studied very low-frequency noise in the ionosphere and fluctuations of the earth's magnetic field.

They have measured the solar wind, monitored solar flares and gathered in formation on the nature and energy of the luminous particles in the auroras.

Among OGO accomplishments: map ping the earth's magnetic field; plotting the puzzling bursts of radio noise from Jupiter; and revealing a surprising boundary layer of ions (charged sub atomic particles) some 16,000 to 24,000 miles out in space. By continuously transmitting such evidence, OGOs have given scientists an unprecedented blue print of the earth's environment.

Pennies for Progress. Designed and built by TRW systems, each OGO is a refrigerator-size box with 14 simultaneously operating instruments pointing in five directions. To maintain the proper altitude for the instruments, the core contains sensors and controls that are used to stabilize the craft. One face al ways points toward earth, another toward the sun, another away from the earth, one away from the sun, and a fifth in the direction the OGO travels. When two 20-ft. instrument booms and two solar panels are fully extended, the OGOs are 49 ft. long and almost 20 ft. wide, the biggest scientific satellites yet produced. According to TRW project Manager Ralph C. Turkolu, "the OGOs are to previous satellites what a jet is to a glider."

Each OGO has two $300,000 tape recorders that store 86 million bits of information, transmit 64,000 bits a second. An OGO can send back twelve hours of stored information from 20 simultaneously operating instruments in only three minutes.

The project has suffered its share of setbacks. After 46 days in orbit, for example, OGO-3 developed a control-mechanism failure and has since operated at only 75% efficiency. But overall, the OGOs have been a resounding success. By week's end, OGO-4 was performing without a sign of trouble. At TRW's Redondo Beach, Calif., plant, scientists and engineers are testing OGO-5 and building OGO-6, both of which will be sent up next year. The entire program will cost about $150 million—mere pennies, considering the dragonflies' scientific achievements.