Space telescope arrives in Washington, D.C.

By Heather Rock Woods

A pioneering space telescope that researchers from Stanford and around the world recently assembled at the Stanford Linear Accelerator Center (SLAC) has taken a continent-sized step in its journey toward launch. The Large Area Telescope (LAT) arrived safely May 14 at the U.S. Naval Research Laboratory (NRL) in Washington, D.C., after a 3,000-mile trip from Menlo Park, Calif., in a special atmospherically controlled truck.

The 3000-kilogram LAT is the primary instrument for the Gamma-ray Large Area Space Telescope (GLAST) mission to detect gamma rays, the most energetic particles of light in the universe. Gamma rays are up to 100 million times more energetic than the average X-ray taken in a dentist's office. GLAST also will sport a smaller instrument, called the GLAST Burst Monitor, to detect lower-energy gamma-ray bursts. Physicists and astronomers expect that this unprecedented look at the gamma-ray sky will reveal vital information about the nature of dark matter, the evolution of stars and the production of energy by supermassive black holes.

"GLAST will probe extreme environments and cataclysmic events in the universe with hope of unraveling some of nature's deepest mysteries," said GLAST LAT Principal Investigator Peter Michelson, a Stanford physics professor with an appointment at SLAC. "The gamma-ray sky is a unique window on our universe, and GLAST will see it like never before."

The mission is an international collaboration of about 150 researchers with significant contributions from NASA, the U.S. Department of Energy (DOE) and foreign institutions. SLAC, a DOE laboratory operated by Stanford University, manages the development of the LAT in collaboration with NASA's Goddard Space Flight Center; Stanford's W.W. Hansen Experimental Physics Laboratory; the University of California-Santa Cruz; the University of Washington; Ohio State University; NRL; Italy's INFN (particle physics organization) and ASI (space agency); France's IN2P3 (particle physics organization) and CEA (atomic energy agency); and institutions in Japan and Sweden. For a complete list of collaborators see:

http://glast.stanford.ed

u.

GLAST is scheduled to launch from Kennedy Space Center in the fall of 2007, ending up in orbit 330 miles above the Earth.

LAT collaborators from around the world designed, built and tested subsystems for the instrument, which was assembled at SLAC. "It was a technical and managerial challenge for SLAC, but in the end the team achieved a great success," said Raymond L. Orbach, director of the DOE's Office of Science.

The 1.8-meter-per-side cube offers an enormous leap in capabilities to examine the invisible gamma-ray universe. It will be at least 30 times more sensitive than previous detectors and have a far greater field of view. Its ability to see what optical telescopes can't comes from particle physics detectors adapted for space conditions. The LAT detects a gamma ray as a result of its conversion into an electron and a positron that then travel through 18 "tracking layers" that indicate the direction from which the gamma ray came.

The LAT left its clean room at SLAC on May 11. Crews from Goddard Space Flight Center in Maryland, which manages the GLAST mission for NASA, transported the instrument across the country.

At the NRL, the LAT will undergo three months of grueling "shake and bake" testing to ensure the instrument will survive the extreme temperatures, noises and vibrations it will endure during launch and in space. Electromagnetic interference tests will double-check that LAT operations do not interfere with the spacecraft's onboard computers.

"We're confident we're going to pass these tests," said LAT Project Manager Lowell Klaisner of SLAC. "Each subassembly has been put through the same set of tests at SLAC at a wider range than they will see at the NRL."

SLAC and Stanford researchers will go to Washington, D.C., to run the tests with NRL staff. After completing the environmental tests, the LAT will be shipped to Arizona, where engineers at General Dynamics C4 Systems will put LAT and the second GLAST instrument on a spacecraft with solar wings and altitude-control and communications devices.

The orbiting LAT will send data to a mission operation center at NASA Goddard, which in turn will relay the data to a computing center at SLAC, where an international team of collaborators will monitor the health and safety of the instrument and process and analyze the data.

"It was a pleasure to work with such a dedicated team on this challenging endeavor," said Persis Drell, director of Particle and Particle Astrophysics at SLAC. "We at SLAC are thrilled to see the LAT taking its next step toward launch."

Editor Note:

Photos of the Large Area Telescope leaving the Stanford Linear Accelerator Center and arriving at the Naval Research Laboratory are available at http://home.slac.stanford.edu/pressreleases/2006/20060515photos.htm.

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