Washington - NASA launched its Interstellar Boundary Explorer (Ibex) on Sunday to examine the weakening solar wind, which shields planets in the solar system from dangerous cosmic rays. Over the next two years, the Ibex spacecraft will conduct extremely high-altitude orbits above Earth to investigate and capture first images of processes taking place at the interstellar boundary - the farthest reaches of the solar system.
"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 Ibex principal investigator David J McComas.
Cosmic rays pose health threats to astronauts and can wreak havoc with electronics, so must be taken into account when launching satellites.
Ibex may confirm that the sun's heliosphere or the protective bubble surrounding the solar system, is shrinking and weakening. It will also be the first spacecraft to image the interactions between the hot solar wind that slams into the cold expanse of space.
Last month, data from the joint National Aeronautics and Space Administration and European Space Agency Ulysses solar mission revealed that the solar wind is at a 50-year low, potentially opening up the solar system to more dangerous rays from outer space.
Researchers were not surprised that the solar wind has decreased. In fact, the amount of radiation sent off by the sun operates in an 11-year cycle, but this dip was lower than those recently observed. Still, it may be in line with centuries-long patterns, said Nancy Crooker, a research professor at Boston University.
"This is not a good time to be travelling in space," Crooker said, but noted that astronauts travelling to the International Space Station are in no additional danger because the ISS is close enough to Earth to be protected by its magnetic shield.
However, the lower solar wind and resulting exposure to cosmic rays will have to be considered as NASA plans to return astronauts to the Moon and beyond.
Ibex was launched aboard a Pegasus rocket, NASA's smallest orbital vehicle, which was dropped from under the wing of an L-1011 aircraft flying over the Pacific Ocean. The rocket would carry Ibex to an orbit about 200,000 miles above Earth.
