The Interstellar Boundary Explorer (IBEX) is a NASA satellite tasked with creating a map featuring boundaries between interstellar space and our Solar System. Launched on a Pegasus XL rocket from Vandenberg Airforce Base in California with an assist from Lockheed’s L-1011 Stargaze, IBEX entered into orbit on October 19, 2008. 

The Southwest Research institute designed the craft and operates the mission while collaborating with the Los Alamos National Laboratory and Lockheed Martin Advanced Technology Center. Originally intended to last two years to observe the entirety of our Solar System and establish its official boundaries, IBEX completed its mission in 2011, resulting in an additional two year extension to resume observations through 2013. As of today, the mission continues operations into its eleventh year.


The sun sends out a constant flow of solar material called the solar wind, which creates a bubble around the planets called the heliosphere. The heliosphere acts as a shield that protects the planets from interstellar radiation. Credit: NASA

IBEX performs extensive study on the heliosphere, the bubble-like shell created by the Sun which houses our Solar System. In 2010, IBEX  discovered the helioshere lacks a bow shock, the boundary between the magnetosphere and interstellar space, startling physicists and astronomers worldwide. In 2011, the spacecraft’s orbit was adjusted to avoid close proximity to the Moon’s gravity, allowing for improved fuel usage and a more stable orbit, extending the satellite’s usefulness for another 40 years.

The spacecraft’s unique design enables it to create images with particles instead of light, allowing for the detection energetic neutral atom (ENA) emissions, high energy particles undetectable by conventional telescopes that compose the Solar System’s boundary when interacting with solar wind and interstellar space. IBEX detects around 500 of these particles a day, most emerging from outside the Solar System,  though ENAs have been observed coming from Earth’s magnetosphere. The source of most of these emissions remains a mystery, however. 

IBEX discoveries illustrate the environment in our Solar System, allowing scientists greater insight into understanding our Cosmic neighborhood, and the many strange elements  and mechanics that remain hidden from the naked eye.

Energetic Neutral Atoms (ENAs) emitting from a region outside Earth’s magnetopause where nearly stationary protons from the solar wind interact with the tenuous cloud of hydrogen atoms in Earth’s exosphere.
Credits: NASA’s Goddard Space Flight Center

IBEX map of the complex interactions occurring at the edge of the solar system which revealed a giant ribbon, an anomaly described as a reflection where solar wind particles heading into interstellar space are reflected back into the Solar System by a galactic magnetic field. Credits: NASA/IBEX