
LEO
Heliophysics
IBEX
Interstellar Boundary Explorer
FACTS AT A GLANCE
Mission Description
As part of a Southwest Research Institute team led by Principal Investigator Dr. David McComas,
Orbital was selected in January 2005 to develop, build and launch a small spacecraft for NASA’s
Interstellar Boundary Explorer (IBEX) mission. The spacecraft is based on Orbital’s LEOStar-1™
spacecraft product line.
The IBEX satellite orbits the Earth every eight days on a highly-elliptical path that takes it to an apogee
of 320,000 kilometers (approximately 80 percent of the distance to the Moon) to make the rst
comprehensive map of the boundary between our Solar System and interstellar space. Measuring
this interstellar interaction is important for understanding our protection from galactic cosmic rays –
energetic particles from beyond the Solar System – that could pose health risks to future astronauts
exploring deep space.
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IBEX was launched on October 19, 2008, aboard Orbital's Pegasus
Kwajalein Atoll launch site in the central Pacic Ocean. The spacecraft incorporated an on-board
solid rocket motor and hydrazine propulsion system to propel it to the nal high-altitude orbit beyond
Earth’s magnetosphere, as required by IBEX’s scientic instrument.
launch vehicle from the
Spacecraft
The IBEX spacecraft is based on Orbital’s highly reliable LEOStar-1 spacecraft platform, subsystems
and supporting software, which has a proven track record of success on a total of 45 missions.
The payload consists of two narrow angle image sensors (IBEX-Hi and IBEX-Lo) and a Combined
Electronics Unit (CEU).
IBEX's orbit takes it up to 200,000 miles
from Earth.
Six months into its mission, IBEX
surveyed the entire sky to reveal the
structure of the edges of our solar
system.
Mission:
NASA Small Explorer (SMEX) Program
Customer:
Southwest Research Institute –
San Antonio, Texas
IBEX in Orbital's Dulles, Virginia satellite
manufacturing facility

IBEX
Specications
Spacecraft
Mass: <110 kg (243 lb.)
Power: <85 W
Stabilization: Sun-pointing major axis spinner
Orbit: 7,000 km perigee altitude, 50 Earth-radii apogee altitude
Mission Life: 24 months (baseline mission)
Payload
Two single pixel image sensors (IBEX-Hi and IBEX-Lo)
Combined Electronics Unit (CEU)
Launch
Launch Vehicle: Pegasus
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XL
Site: Kwajalein, Marshall Islands
Date: October 19, 2008
IBEX Mission
In its elliptical orbit around the Earth, the IBEX spacecraft is pointed towards the
sun, and spins continuously. Two narrow angle image sensors (IBEX-Hi and IBEX-
Lo) are positioned perpendicular to the spin axis. These special imagers detect
neutral atoms from the solar system’s outer edge, enabling scientists to map the
boundary between our Solar System and interstellar space.
Mission Partners
Southwest Research Institute
Principal investigator, mission management, science
instruments and operations
Orbital Sciences Corporation
Spacecraft and launch vehicle design, fabrication, test,
launch operations, and mission operations
Additional Partners
Lockheed Martin Advanced Technology Center
Applied Physics Laboratory
Los Alamos National Laboratory
Alliant Techsystems
University of New Hampshire
Adler Planetarium and Astronomy Museum
Orbital Sciences Corporation
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