Interstellar Boundary Explorer
The Pegasus XL launch vehicle released the IBEX satellite at 17:47:23 UTC on the 19th of October 2008. This specific moment occurred after a Lockheed L-1011 Stargazer mother airplane flew from Vandenberg Air Force Base to Kwajalein Atoll in the central Pacific Ocean. The aircraft arrived at the atoll on the 12th of October 2008, positioning the mission for an equatorial drop. Launching near the equator allowed the rocket to lift as much as 50 kilograms more mass to orbit than it could have achieved from Florida. Dr. David J. McComas led the mission team from the Southwest Research Institute during this critical deployment phase. Orbital Sciences Corporation manufactured the satellite bus and conducted environmental testing before the flight system reached its final destination.
In June 2011, engineers shifted the spacecraft into a new orbit that raised its perigee to more than 60,000 kilometers. This adjustment created a period of one third of a lunar month to avoid taking the craft too close to the Moon. Lunar gravity previously threatened to negatively affect the satellite's trajectory and fuel reserves. The new orbit allows IBEX to use less fuel to maintain stability while increasing its useful lifespan to more than 40 years. The original orbit ranged from about 300 kilometers to roughly 80% of the distance to the Moon. Moving out of Earth's magnetosphere became essential for making scientific observations without charged-particle interference. Telemetry downlinks now occur when the satellite remains within the magnetosphere at lower altitudes.
The payload consists of two energetic neutral atom imagers known as IBEX-Hi and IBEX-Lo. Each sensor features a collimator limiting fields of view to roughly 7 degrees by 7 degrees. A conversion surface transforms neutral hydrogen and oxygen into ions for detection. An electrostatic analyzer suppresses ultraviolet light and selects ions within specific energy ranges. IBEX-Hi records particle counts in a higher energy band ranging from 300 eV to 6 keV. IBEX-Lo operates in a lower energy band between 10 eV and 2 keV. On average, IBEX-Hi detects about 500 particles per day while IBEX-Lo captures fewer than 100 daily. Both sensors function as single-pixel cameras with a Combined Electronics Unit controlling voltages on the collimator and ESA.
Initial data revealed a previously unpredicted very narrow ribbon that is two to three times brighter than anything else in the sky. This structure appeared in full sky maps generated every six months across all directions. Initial interpretations suggest the interstellar environment has far more influence on structuring the heliosphere than anyone previously believed. In October 2010, significant changes were detected in the ribbon after six months based on the second set of observations. It remains unknown what creates these energetic neutral atom emissions. The Sun travels through the Local Interstellar Cloud while the heliosphere's size determines its shielding power from cosmic rays. Should IBEX detect shape changes in the ribbon, it could reveal how the heliosphere interacts with the Local Fluff.
By 2012, over 100 scientific papers related to IBEX were published under the direction of the principal investigator. Dr. McComas described this output as an incredible scientific harvest for the mission team. Results from July 2013 revealed a four-lobed tail on the Solar System's heliosphere. IBEX discovered that the heliosphere has no bow shock and measured its speed relative to the local interstellar medium at 26 kilometers per second. Those speeds equate to 25% less pressure on the Sun's heliosphere than previously thought. The spacecraft continues operation in its extended mission phase beyond the original two-year baseline. A follow-on project called the Interstellar Mapping and Acceleration Probe now builds upon these findings.
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Common questions
When was the Interstellar Boundary Explorer satellite launched?
The Pegasus XL launch vehicle released the IBEX satellite at 17:47:23 UTC on the 19th of October 2008. This specific moment occurred after a Lockheed L-1011 Stargazer mother airplane flew from Vandenberg Air Force Base to Kwajalein Atoll in the central Pacific Ocean.
Who led the mission team for the Interstellar Boundary Explorer project?
Dr. David J. McComas led the mission team from the Southwest Research Institute during this critical deployment phase. Orbital Sciences Corporation manufactured the satellite bus and conducted environmental testing before the flight system reached its final destination.
What orbit did engineers shift the Interstellar Boundary Explorer into during June 2011?
In June 2011, engineers shifted the spacecraft into a new orbit that raised its perigee to more than 60,000 kilometers. This adjustment created a period of one third of a lunar month to avoid taking the craft too close to the Moon.
How many particles does the IBEX-Hi sensor detect each day compared to IBEX-Lo?
On average, IBEX-Hi detects about 500 particles per day while IBEX-Lo captures fewer than 100 daily. Both sensors function as single-pixel cameras with a Combined Electronics Unit controlling voltages on the collimator and ESA.
What major discovery did the Interstellar Boundary Explorer make regarding the heliosphere in July 2013?
Results from July 2013 revealed a four-lobed tail on the Solar System's heliosphere. IBEX discovered that the heliosphere has no bow shock and measured its speed relative to the local interstellar medium at 26 kilometers per second.