Unmanned Space Probes Call For World Teamwork
While international astronaut teams catch the spotlight, space scientists focus on a show of their own. It's an armada of scientific satellites due to take up positions during the next few weeks.
Some will study the farthest galaxies. Others will put the sun and its magnetized ''wind'' of charged particles under scrutiny. That will help scientists better understand how that wind sometimes disrupts communications and electric-power transmission. And, like the shuttle-Mir teamwork, this comprehensive solar program illustrates how major space projects can only proceed through international partnerships these days.
Take SOHO, for example, the Solar Heliospheric Observatory that is now waiting for a Dec. 7 launch at Cape Canaveral. The US National Aeronautics and Space Administration (NASA) and the 14-member European Space Agency (ESA) are splitting its roughly one-billion-dollar cost about 50-50. It's a key part of the new solar exploration.
''[Yet] the only way ESA and NASA could have conducted this program was to collaborate and financially share in the funding,'' says SOHO project scientist Arthur Poland at NASA's Goddard Space Flight Center in Greenbelt, Md. He adds that ''SOHO represents the way future enterprises between NASA and ESA will operate.''
That goes for the entire International Solar-Terrestrial Physics (ISTP) program. Japan has already placed its Geotail satellite where it can monitor conditions in our planet's long ''tail'' of magnetic fields and electrically charged particles. It's swept out by the solar wind as it blows past Earth's so-called magnetosphere. That's the region dominated by Earth's magnetic field - where aurorae flash and magnetic storms take shape. ESA plans to launch four satellites early next year in a project called Cluster to monitor that region. And NASA plans to launch yet another magnetospheric monitor early next month. Called Polar, it will orbit over Earth's poles.
Polar complements NASA's Wind satellite, launched Nov. 1, 1994. Traveling a stretched-out figure-eight orbit ranging 18,000 to 990,000 miles from Earth, Wind has already shown the value of intensive monitoring. Last Oct. 18, a magnetized cloud of solar particles 65 million miles across swept past the satellite at 2.1 million miles an hour. When it hit Earth's magnetosphere, aurorae flashed for two days. Had the Polar and Cluster satellites been in place, they would have given a detailed account of what happened. As it was, officials concerned about electrical disruptions had advanced warning that trouble was coming.
Now SOHO is moving into position to maintain continuous watch on the sun itself. Besides looking for visible solar activity, it will study conditions deep within the star. Like seismologists who study Earth's interior with earthquake seismic waves, scientists who now call themselves helioseismologists will use surface undulations to study conditions in the solar depths.
The ISTP's aim is to focus all this orbiting observational power to get a better understanding of the space environment around us and how it affects Earth. This would simply be impossible without major international cooperation. There still are less-costly missions that individual agencies can mount, however. ESA's Infrared Space Observatory, for instance, now is moving into operational position. It left the Kourou space center in French Guiana Nov. 16. The first major infrared observatory to orbit in 12 years, it will study objects by infrared light both within our solar system and in distant galaxies. Its instruments are sensitive enough ''to detect an ice-cold object the size of a human being 100 km away,'' according to ESA.
Put it all together and there's a lot of action in space exploration that doesn't require astronauts. What's more, the information and images from many of these missions will be available on the Internet. In this electronic age, even computer-savvy lay people can join in the scientists' fun.