In this section you can determine where Fermi pointed in the past and is scheduled to point in the future.
The following are utilities that provide you with these capabilities:
Following the March 16, 2018 anomaly which prevents the movement of one of Fermi's solar arrays, a weekly observing timeline is created by the FSSC to schedule sky survey observations in three modes. The observing mode used depends on the angle between the spacecraft's orbital plane and the Sun, i.e. the beta angle. This angle varies on both a yearly timescale and with an approximate period of 46 days driven by the precession of Fermi's orbit. More information about beta angle dependent observing modes and sky coverage is available here.
Assigned a Fermi mission week number (e.g. 513), the weekly observing timeline is prepared starting with an preliminary draft to facilitate mission planning about 3 weeks before implementation. One week before upload to the observatory a final timeline is generated based on the preliminary draft. An as-flown timeline records the observations as performed. The latest version of the timelines will be posted.
The following table compares the different timelines.
|If an observation is on this timeline...||Then...|
|Preliminary weekly observing timeline||The observation will most likely occur when scheduled, but could be rescheduled.|
|Final weekly observing timeline||The observation will occur when scheduled, unless disrupted.|
|As-flown timeline||Observation occurred at the reported time|
The FSSC compares the timeline as actually implemented with the planned timeline and updates the observing timeline with the results.
For the forseeable future Fermi will be operated in a beta angle dependent sky survey mode.