Fermi Gamma-ray Space Telescope

Observatory Status

Fermi Observations for MW 859

Mission Week 859 begins with a 10-minute freeze observation during which a symmetric +/-50 deg. profile is loaded. Then, on DOY 319 (2024-11-14) at 18:40 UT a 10-minute freeze observation occurs during which a Star Tracker CCD dump will be performed. Next, on DOY 321 (2024-11-16) at 19:45 UT a 10-minute freeze observation occurs during which an asymmetric -50/+60 deg. profile is loaded. Following this, on DOY 324 (2024-11-19) at 11:03 UT a 10-minute freeze observation occurs during which a -50 deg. modified sine profile is loaded. This profile continues until the end of the mission week. The survey repeat period DECREASED from 5684s to 5683s. Note that positive rock angles are south, and negative rock 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, after which Fermi began science operations. A general Fermi mission overview and related media resources can be found here.

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). For more details on the instrument hardware, see the home pages of the GBM and the LAT. Some information about the LAT's Anti-Coincidence Detector (ACD) is available here.

From the start of science operations in August 2008 the adopted default observation mode for the LAT was a survey mode, continuously scanning the sky to provide all-sky coverage every two orbits. Other survey strategies` and inertial pointed Target of Opportunity (ToO) observations motivated by the scientific community were also employed.

On March 16 2018, the spacecraft suffered a mechanical failure and can no longer move one of its solar arrays. As a result of that anomaly, a new sky survey strategy has been implemented. Alternative survey strategies and pointed ToO observations will not be done for the forseeable future. Please see this page for further details of the new sky survey strategy.

For the results of LAT and GBM observations, see:

More information on Fermi Observations: