IBEX is a breakthrough mission that was achieved with a small, lightweight spacecraft, launched using a Pegasus rocket dropped from a L–1011 aircraft. Prior to the IBEX mission, all other NASA spacecraft that had used the Pegasus launch system utilized it only to reach low–Earth orbit. After IBEX used the Pegasus system to reach low–Earth orbit, it then had an additional solid rocket motor and its own onboard propulsion system to boost itself into a high altitude orbit that, at its farthest point, reaches about 200,000 miles (320,000 kilometers) from Earth.
The IBEX spacecraft spins about 4 times per minute and keeps its solar panels pointed at the Sun at all times. Small onboard thrusters fire twice per orbit to maintain the proper orientation of the solar panels. Perpendicular to the solar panels, IBEX has two sensors, called IBEX–Hi and IBEX–Lo, which are designed to detect energetic neutral atoms, which are neutral atoms that travel very quickly and are not affected by magnetic fields. The IBEX sensors collect neutral atoms all year long, but measurements at various times of year can allow the scientists to not only study neutral atoms created at our Solar System’s outer boundaries, but also neutral atoms drifting in from outside our Solar System, neutral atoms created by the interaction of the solar wind with the surface of our Moon, and neutral atoms created by processes occurring in Earth’s magnetosphere. Details about the different types of IBEX science results achieved using the IBEX sensors are available in the Archived Updates.