NASA probe to study edge of solar system Agence France-Presse

Published: Sunday October 19, 2008





Print This Email This WASHINGTON, (AFP)  The US space agency was on Sunday to launch a space probe that will go into orbit high above earth to study the distant edge of the solar system where hot solar winds crash into the cold outer space.



The Interstellar Boundary Explorer (IBEX) is on a two-year mission to take pictures and chart the mysterious confines of the solar system, located billions of kilometers (miles) from Earth.



The IBEX is equipped with instruments that will allow it to take images and for the first time chart a remote region known as the interstellar boundary, where the solar system meets interstellar space. The area is a vast expanse of turbulent gas and twisting magnetic fields.



"The interstellar boundary regions are critical because they shield us from the vast majority of dangerous galactic cosmic rays, which otherwise would penetrate into Earth's orbit and make human spaceflight much more dangerous," said David McComas, IBEX principal investigator from the Southwest Research Institute (SwRI) in San Antonio, Texas.



The only information that scientists have of this distant region are from the twin Voyager 1 and 2 probes, launched in 1977 and still in service today.



After flying past Jupiter and Saturn, and in the case of Voyager 2, Uranus and Neptune, the probes are on their way to travel beyond the solar system.



In December 2004 Voyager 1 reached an area that scientists describe as the "termination shock" zone, where solar winds crash into the gas of interstellar space, marking the boundary of the solar system.



"The Voyager spacecraft are making fascinating observations of the local conditions at two points beyond the termination shock that show totally unexpected results and challenge many of our notions about this important region," said McComas.



In 2007 Voyager 2 reached the heliosheath -- the area where the termination shock begins -- and on its current path and speed should reach the heliopause in 2010.



The National Aeronautics and Space Administration (NASA) remains in regular contact with the two probes, which return data recorded by their particle detectors.



By 2020 however contact with Voyager probes will be lost because of the weakening of their plutonium generators.



IBEX, armed with two very large aperture single pixel "cameras" that measure energetic neutral atoms, is to produce images of the region that will allow scientists for the first time to better understand what happens when the solar system meets the outer space galaxy.



The mission will also study cosmic radiation, which has a negative impact on human health and space exploration.



The IBEX probe weighs 462 kilos (1016 pounds) and is shaped like an octagon, measuring a mere 52 centimeters (23 inches) high and 97 centimeters (38 inches) across.



The probe is to be launched from the Kwajalein Atoll, a part of the Marshall Islands in the Pacific Ocean, aboard a Pegausus rocket that will be dropped from a large Lockheed L-1011 carrier aircraft flying some 12,000 meters (40,000 feet) above the Marshall Islands.



The Pegasus will put the IBEX in a low orbit some 96 kilometers (60 miles) above the earth. The IBEX spacecraft's own solid rocket motor will then carry the probe into a much higher altitude orbit of around 200,000 miles, NASA said.



The launch window is on Sunday between 1744 GMT and 1752 GMT, NASA said



