NASA is gearing up to launch a new spacecraft to probe the
fringe of the solar system this month where material from the sun hits the cold
expanse of space.
The Interstellar
Boundary Explorer (IBEX) spacecraft is set to lift off atop an air-launched
Pegasus XL rocket Oct. 19 from Kwajalein Atoll, a part of the Marshall Islands
in the Pacific Ocean.
While it won't actually travel beyond all the planets to
investigate the solar system's far reaches, the coffee table-sized spacecraft
must escape the area where Earth's
magnetic field reigns, which could interfere with its measurements. The $169
million observatory is due to climb 200,000 miles (322,000 kilometers) above
Earth and settle into orbit there for a mission of at least two years. For
comparison, the moon orbits about 240,000 miles (385,000 km) from Earth.
"One of [IBEX's] prime goals is to tell us the place of
the solar system in the galaxy," said Eric Christian, IBEX program
scientist at NASA headquarters in Washington, D.C., during a Monday briefing.
"How the solar system moves through the galaxy is scientifically
interesting and may be interesting from an evolution-of-Earth standpoint."
The boundary at the solar system's final frontier was first explored
by the Voyager
1 spacecraft in 2004, when it encountered an invisible shock created as the
charged particles streaming
off the sun hit the neutral gas from interstellar space. This so-called
termination shock marks the beginning of the edge of the solar system.
The spacecraft will utilize a novel three-stage method to
reach its distant orbit around Earth to scan the solar system's edge. Unlike
previous launches of the solid-fueled Pegasus rocket, IBEX will boost itself
beyond its initial orbit using an additional solid rocket motor and a hydrazine
fuel stage, mission managers said.
"IBEX will let us make the first global observations of
the region beyond the termination shock at the very edges of our solar
system," said David J. McComas, IBEX principal investigator from the
Southwest Research Institute (SwRI) in San Antonio, Texas. "This region is
critical because it shields out the vast majority of the deadly cosmic rays
that would otherwise permeate the space around the Earth and other planets."
IBEX plans to create an all-sky map of the interaction
between particles from the solar wind, called the heliosphere, and the material
in the galaxy beyond our solar system. Sometimes, when a neutral atom from
interstellar space passes a positively-charged particle from the sun, an
electron hops from one to the other, making the charged atom neutral. IBEX is
designed to detect these fast-moving neutral particles and trace their
direction back to the solar
system's edge, gradually building up a picture of this chaotic frontier.
"We know that the pictures that IBEX gives us are going
to surprise us, and that's one of the fun things about science," Christian
said. "This is really exciting, it's really going to increase our
knowledge of the heliosphere."
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