NASA scientists and engineers have completed final testing and integration of the GLAST Burst Monitor, a space-based instrument for studying gamma ray bursts.

These bursts, scientists believe, originate in the collapse of massive stars up to 100 times that of our sun, a process that eventually forms a black hole in space and poses unanswered questions to scientists on Earth.

The monitor is one of two instruments on the Gamma-ray Large Area Space Telescope, or GLAST, an orbiting observatory scheduled to launch from NASA's Kennedy Space Center, Fla., in fall 2007.

The GLAST Burst Monitor shipped from NASA's Marshall Space Flight Center, Huntsville, Ala., on July 24. It arrived two days later at General Dynamics C4 Systems, Scottsdale, Ariz., where it will be integrated with the spacecraft.

GLAST's primary instrument, the Large Area Telescope, is nearing completion of four months of environmental testing at the U.S. Naval Research Laboratory, Washington, its final stop before shipment to General Dynamics.

Together, the Large Area Telescope and the GLAST Burst Monitor will observe gamma rays ranging in energy from a few thousand electron volts to many tens of billions of electron volts or higher, the widest range of coverage ever available on a single spacecraft for gamma-ray studies.

"A single gamma-ray burst releases more energy than the sun will release during its entire 4.5 billion-year lifecycle," said the project's principal investigator, Charles Meegan, an astrophysicist at Marshall. "Believed to be the explosions of massive stars, gamma-rays remain one of the greatest mysteries of astrophysics."

More energetic than X-rays, gamma rays are the highest-energy form of electromagnetic radiation. When a burst occurs, the GLAST Burst Monitor will detect gamma rays from the explosion. Within seconds, the instrument will identify the location of the burst. This information will be sent to scientists on the ground, and if the burst is exceptionally strong, the spacecraft will reorient its position so that the Large Area Telescope also can observe the burst. Data gleaned by GLAST will span an energy range hundreds of times larger than ranges monitored by earlier instruments.

The GLAST project builds on previous experience developing and integrating large complex space systems. To design and test the GLAST Burst Monitor, Marshall Center scientists tapped more than two decades of experience building and operating the Burst and Transient Source Experiment, also known as BATSE. One of four instruments on NASA's Compton Gamma Ray Observatory, BATSE observed more than 2,700 gamma-ray bursts from 1991 to 2000. The instrument fueled a greater understanding of these powerful events.

To design the GLAST Burst Monitor, Marshall scientists collaborated with scientists from the Max Planck Institute for Extraterrestrial Physics, Garching, Germany, working with NASA through an agreement with the German Aerospace Center. The Marshall manages the GLAST Burst Monitor with the Max Planck Institute, which built the monitor's crystal detectors - the main component for intercepting gamma rays. Scientists from the Marshall and the University of Alabama, Huntsville, provided flight electronics, software and testing for the instrument.

"The effort tapped local and international expertise," said Meegan. "When the GLAST Burst Monitor delivers its first set of data - about a month after launch - it will culminate years of research, design and testing by many dedicated individuals."

NASA Goddard Space Flight Center in Greenbelt, Md., manages the mission. The Stanford Linear Accelerator Center (a DOE Office of Science national laboratory), Menlo Park, Calif., manages the Large Area Telescope with collaborators at Goddard, University of Calif., Santa Cruz; University of Washington, Seattle; Ohio State University, Columbus; U.S. Naval Research Laboratory; and institutions in France, Italy, Japan, and Sweden. Marshall manages the GLAST Burst Monitor with the Max Planck Institute. General Dynamics is responsible for spacecraft and instrument integration, and Sonoma State University, Rohnert Park, Calif., manages education/public outreach efforts for the Large Area Telescope.