The HEASARC welcomes your participation in a brief survey to capture how users access and utilize HEASARC data, software, and services. The outcome(s) of this survey will be used to guide, prioritize, and plan our activities and development in the coming years. It contains 18 questions, generally takes just a few minutes to complete, and your answers will remain totally anonymous. We thank you in advance for your valuable feedback.
Fermi Gamma-ray Space Telescope

Observatory Status

Fermi Observations for MW 550

Mission Week 550 starts with a continuation of the -50 degree only rock profile from MW 549. On day 348 (Dec 14) at 11:26 there is a 10 minute freeze observation during which a sine profile (for both orbit day and orbit night) with an amplitude of +/- 50 degrees is loaded. This profile continues until the end of the week. Note that positive rock angles are south, and negative angles are north.

» More Timeline Info

The Fermi Gamma-ray Space Telescope was launched from Kennedy Space Center on June 11, 2008. The observatory checkout phase completed on August 11, 2008, and Fermi is now in nominal science operations. The current status (and beautiful graphics) can be found at

The Fermi spacecraft supports two gamma-ray instruments; the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM). The LAT is a wide-field gamma-ray telescope (20 MeV - 300 GeV). From the start of regular observations in August 2008 until December 2013 the LAT continuously scanned the sky, providing all-sky coverage every two orbits. In December 2013 the LAT will transition to a modified observing strategy that combines pointed observations, designed to increase coverage of the Galactic center, together with sky survey observations. Details of the new observing strategy are provided here. LAT observations may also be interrupted by occasional additional pointed observations, including target of opportunity observations, and autonomous repointing of the observatory to follow GRB afterglows, and by regular passages through the South Atlantic Anomaly (a region of high particle backgrounds). The GBM is an all-sky monitor (10 keV - 25 MeV) that detects transient events such as occultations and gamma-ray bursts. GBM detections of strong GRBs can result in an autonomous repoint of the observatory to allow the LAT to obtain afterglow observations.

For more details on the instrument hardware, see the home pages of the GBM, the LAT, and the ACD.

For the results of LAT and GBM observations, see:

More information on Fermi Observations: