Gamma-ray Large Area Space Telescope

From Wikipedia, the free encyclopedia

 This article contains information regarding a satellite that is scheduled to launch in the next 2 days.

Details may change as the countdown and ascent progress. Launch details: ULA will use a Delta II 7920H to launch GLAST for NASA. Launch will occur from LC-17B at CCAFS. • Live countdown clock • Webcast

Launch is scheduled for 11 June 2008 at 15:45 -17:40 UTC. See 2008 in spaceflight and the Spaceflight Portal for further details.
edit this messagebox

Contents

The Gamma-ray Large Area Space Telescope, or GLAST, is a future space-based gamma-ray telescope, designed to explore the high-energy Universe. It will study astrophysical and cosmological phenomena such as active galactic nuclei, pulsars, other high-energy sources, and dark matter. GLAST is a joint venture of NASA, the United States Department of Energy, and government agencies in France, Germany, Italy, Japan, and Sweden.[1]

On February 8, 2008 NASA announced it was seeking suggestions for a new name for GLAST that, "Will capture the excitement of GLAST's mission and call attention to gamma-ray and high-energy astronomy."[2]

[edit] Overview

GLAST logo
GLAST logo

GLAST includes two scientific instruments, the Large Area Telescope (LAT) and the GLAST Burst Monitor (GBM). The LAT is an imaging gamma-ray detector which detects photons with energy from about 30 million to about 300 billion electron volts (30 MeV - 300 GeV). The GBM consists of 14 scintillation detectors which detect bursts of photons from 8 keV to 30 MeV.

General Dynamics Advanced Information Systems (formerly Spectrum Astro) in Gilbert, Arizona built the spacecraft that will carry the instruments. It will travel in a low, circular orbit with a period of about 95 minutes. Its normal mode of operation will maintain its orientation so that the instruments will look away from the earth, with a "rocking" motion to equalize the coverage of the sky. The view of the instruments will sweep out across most of the sky about 16 times per day. The spacecraft can also maintain an orientation that points to a chosen target.

The construction of both instruments is complete. They have undergone environmental testing, being subjected to vibration, vacuum, and high and low temperatures to ensure that they can withstand the stresses of launch and continue to operate in space. They were integrated with the spacecraft at the General Dynamics facility in Gilbert, Arizona.

Data from the instruments will be available to the public through the GLAST Science Support Center web site. Software for analyzing the data will also be available. Scientists with plans for research will be able to apply to the Guest Investigator program.

On 7 February 2008, NASA's Alan Stern, associate administrator for Science at NASA Headquarters, launched a public competition, closing 31 March 2008, to re-name GLAST in a way that would "capture the excitement of GLAST’s mission and call attention to gamma-ray and high-energy astronomy... something memorable to commemorate this spectacular new astronomy mission... a name that is catchy, easy to say and will help make the satellite and its mission a topic of dinner table and classroom discussion."[3]

[edit] Mission

Artist's conception of the GLAST satellite
Artist's conception of the GLAST satellite

The key scientific objectives of the GLAST mission are:[4]

  • To understand the mechanisms of particle acceleration in active galactic nuclei (AGN), pulsars, and supernova remnants (SNR).
  • Resolve the gamma-ray sky: unidentified sources and diffuse emission.
  • Determine the high-energy behavior of gamma-ray bursts and transients.
  • Probe dark matter and early Universe.
  • Search for evaporating primordial micro black holes [MBH] from their presumed gamma burst signatures [Hawking Radiation component].

NASA designed the mission with a five-year lifetime, with a goal of ten years of operations.[5]

[edit] Launch

On 2008-03-04 the spacecraft arrived at the Astrotech payload processing facility in Titusville, Florida.[6] It will launch from pad B at Cape Canaveral Air Force Station Launch Complex 17 aboard a Delta 7920H-10C rocket. On 2008-06-04, after several previous delays, launch status was retargeted for June 11 at the earliest, [7][8] the most recent delays resulting from the need to replace the Flight Termination System batteries.[9]

The launch window thru 2008-08-07 extends from 11:45 a.m. until 1:40 p.m. EDT daily.[9] GLAST will reside in a low-earth circular orbit at an altitude of 550 kilometers, and at a 28.5 degree inclination.[10]

[edit] GLAST Science Packages

[edit] GBM

GBM is an acronym for GLAST Burst Monitor; the GBM detects sudden flares of gamma rays produced by gamma ray bursts and solar flares. Its scintillators are on the sides of the spacecraft to view all of the sky which is not blocked by the earth. The design is optimized for good resolution in time and photon energy.

[edit] GBM Participating Institutions

[edit] US Team Institution

[edit] German Team Institution

[edit] LAT

LAT is an acronym for Large Area Telescope; the LAT detects individual gamma rays using technology similar to that used in terrestrial particle accelerators. Photons hit thin metal sheets, converting to electron-positron pairs. These charged particles pass through interleaved layers of silicon microstrips, causing ionization which produce detectable tiny pulses of electric charge. Researchers can combine information from several layers of this tracker to determine the path of the particles. After passing through the tracker, the particles enter the calorimeter, which consists of a stack of caesium iodide scintillator crystals to measure the total energy of the particles. The LAT's field of view is large, about 20% of the sky. The resolution of its images is modest by astronomical standards, a few arc minutes for the highest-energy photons and about 3 degrees at 100 MeV. The LAT may be a bigger and better successor to the EGRET instrument on NASA's Compton Gamma Ray Observatory satellite in the 1990s. Several countries produced the components of the LAT, who then sent the components for assembly at the Stanford Linear Accelerator Center (SLAC).

[edit] LAT Participating Institutions

[edit] US Team Institutions

[edit] Japanese Team Institutions

[edit] Italian Team Institutions

[edit] French Team Institutions

[edit] Swedish Team Institutions

[edit] Education and Public Outreach

Education and Public Outreach are important components of the GLAST project. The main GLAST education and public outreach website at http://glast.sonoma.edu offers gateways to resources for students, educators, scientists, and the public. NASA’s Education and Public Outreach (E/PO) group operates the GLAST education and outreach resources at Sonoma State University.

[edit] References

  1. ^ An Astro-Particle Physics Partnership Exploring the High Energy Universe - List of funders. SLAC. Retrieved on August 9, 2007.
  2. ^ Name that Space Telescope!. NASA (2008-02-08).
  3. ^ NASA Calls for Suggestions to Re-Name Future Telescope Mission, NASA, 7 February 2008, accessed 10 February 2008
  4. ^ The Mission. SLAC. Retrieved on August 9, 2007.
  5. ^ The GLAST Mission - GLAST Overview, mission length. NASA. Retrieved on August 9, 2007.
  6. ^ GLAST Spacecraft Arrives in Florida to Prepare for Launch. NASA.
  7. ^ Spaceflight Now - Tracking Station - Worldwide launch schedule. Retrieved on 2008-06-04.
  8. ^ GLAST Mission Coverage - Latest News. Retrieved on 2008-06-04.
  9. ^ a b NASA - Expendable Launch Vehicle Status Report. NASA (2008-06-06). Retrieved on 2008-06-09.
  10. ^ The GLAST Mission - GLAST Overview, orbital information. NASA. Retrieved on August 9, 2007.

[edit] External links

Wikimedia Commons has media related to: