Orbital Fermi User Manual
Fermi, Mission description, Spacecraft

Astrophysics
• Fermi represents a collaboration
of astronomers, physicists, and
engineers at NASA, the U.S.
Department of Energy, U.S.
universities, and institutes and
universities in France, Germany, Italy,
Japan, and Sweden
• Spacecraft design based on Orbital's
flight-proven LEOStar-3 standard bus.
• 565 km circular Low Earth Orbit
mission
• Fermi carries two instruments: the
Large Area Telescope (LAT) and the
GLAST Burst Monitor (GBM).
• The LAT weighs over 6,000 lb
with almost a million channels of
electronics, but it uses less than half
the power of an ordinary hair dryer.
• Fermi orbits the Earth every 96
minutes. It is oriented to point the
instruments upward at all times, so
the Earth does not block the view. On
alternate orbits, Fermi rocks to the left
and right, allowing the instruments to
survey the entire sky in two orbits.
Customer:
NASA Goddard Space Flight Center
FACTS AT A GLANCE
Fermi in final checkout. (NASA photo)
Fermi
Orbiting Gamma-Ray Observatory
LEO
Mission Description
Formerly known as the Gamma-Ray Large Area Space Telescope (GLAST), the Fermi Gamma-Ray
Space Telescope (Fermi) is a next generation, high-energy gamma-ray orbiting observatory designed
to probe black hole particle jets, gamma-ray bursts, dark matter, and other energetic phenomena by
observing gamma rays. Fermi makes observations of celestial gamma-ray sources in the energy band
extending from 10 kiloelectron volt to more than 300 gigaelectron volt; the broadest energy coverage
ever provided by a single spacecraft for gamma-ray studies. It follows in the footsteps of the Compton
Gamma-Ray Observatory and joins its orbiting sister, the Swift Gamma-Ray Observatory.
Spacecraft
Under contract to NASA Goddard Space Flight Center (GSFC), Orbital designed and manufactured the
spacecraft, integrated the NASA-furnished payload instruments, and performed full system testing of
the observatory, including EMI-EMC and environmental tests. This follows a similar effort at Orbital for
the development of NASA’s highly successful Swift Gamma-Ray Observatory, launched in 2004. The
spacecraft design was based on Orbital's flight-proven LEOStar
™
-3 standard bus.