May 17, 2006
‘Extreme Physics’ Observatory Prepares for Flight
Scientists and engineers have completed assembly of the primary instrument for the Gamma-ray Large Area Telescope, or GLAST, a breakthrough orbiting observatory scheduled to launch from NASA Kennedy Space Center in the fall of 2007.
The main instrument, called the Large Area Telescope, or LAT, arrived at the U.S. Naval Research Laboratory (NRL) in Washington for environmental testing on May 14. LAT had left the Stanford Linear Accelerator Center (SLAC) in Menlo Park, Calif., where it was assembled, on May 11 for its cross-country journey in a special atmospherically-controlled truck.
This novel and highly anticipated mission, led by NASA with the Department of Energy and international partners, brings together the astrophysics and particle physics communities.
"With GLAST, physicists will be able to search for signals of new laws of physics and astronomers will gain valuable information about the evolution of the universe," said LAT Principal Investigator Prof. Peter Michelson of Stanford University. "The completion of the LAT assembly and its shipment from SLAC are major milestones in its development."
GLAST, a gamma-ray observatory, will detect light many billions of times more energetic than what our eyes can see or what optical telescopes such as Hubble can detect. Key targets include powerful particle jets emanating from enormous black holes, and possibly the theorized collisions of dark matter particles. The LAT will be at least 30 times more sensitive than previous gamma-ray detectors and will have a far greater field of view.
"The relative range of light energies that the LAT can detect is thousands of times wider than that of an optical telescope, which captures only a thin slice of the electromagnetic spectrum," said GLAST Project Scientist Dr. Steven Ritz of NASA Goddard Space Flight Center in Greenbelt, Md. "GLAST offers a huge leap in capabilities in this important energy band, and it opens a wide window for exploration and discovery."
Unlike visible light, gamma rays are too energetic to be focused by traditional telescope mirrors onto a detector. The LAT will employ detectors that convert incoming gamma rays into electrons and their antimatter partners, called positrons. This technique, a change of light into matter as described by Einstein's equation E=mc^2, is called pair conversion; and it will enable scientists to track the direction of gamma rays and measure their energy.
The LAT will now undergo three grueling months of "shake and bake" testing to ensure it will survive the intense vibration and noise during launch and operate properly in space. Electromagnetic interference tests also will be performed to ensure LAT operations do not interfere with the spacecraft. When testing is finished at NRL, the instrument will be shipped to Arizona, where engineers at General Dynamics C4 Systems will integrate LAT and a second instrument, the GLAST Burst Monitor, onto the spacecraft.
"The mission is progressing extremely well," said GLAST Project Manager Kevin Grady of NASA Goddard. "The mission's gamma-ray tracking detector is the largest ever constructed. Completing the LAT integration is a culmination of efforts of numerous collaborators from around the globe."
"Building the LAT was a fabulous team effort," said Persis Drell, Director of Particle and Particle Astrophysics at SLAC. "It was a pleasure to work with such a dedicated team on this challenging endeavor. We at SLAC are thrilled to see the LAT taking its next step towards launch."
NASA Goddard manages the GLAST mission. The LAT was built with significant contributions from NASA, U.S. Department of Energy, and foreign collaborating institutions. The Stanford Linear Accelerator Center at Stanford University manages the LAT, which includes collaborators at NASA Goddard, University of Calif., Santa Cruz, University of Washington, Ohio State University, NRL, and institutions in France, Italy, Japan, and Sweden. NASA Marshall Space Flight Center manages the GLAST Burst Monitor in collaboration with the Max Planck Institute in Germany. General Dynamics C4 Systems is building the spacecraft and is responsible for instrument integration. Education and Public Outreach efforts for the GLAST mission are coordinated by Sonoma State University.
View photos of the LAT departing SLAC and arriving at NRL at: