Five years ago today — October 19, 2008 — a Pegasus-XL rocket lofted a satellite designed to study the edge of the solar system.
(IBEX. NASA image from Wikimedia Commons.)
From its L-1011 cargo plane flying near Kwajalein Island in the Pacific Ocean, the Pegasus carried the IBEX (Interstellar Boundary EXplorer) satellite to orbit. The probe specifically monitors hydrogen and oxygen atoms in the vicinity of the heliosphere where the solar wind interacts with elements in interstellar space.
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