Fermi Gamma-ray Space Telescope paths

The Fermi Gamma-ray Space Telescope orbits planet Earth every 95 minutes. It explores the cosmos and by design, it rocks to the north and then to the south on alternate orbits in order to survey the sky with its Large Area Telescope (LAT). Those are the paths of gamma-ray sources from the spacecraft’s perspective, as a result of multiple cycles.  Credit: NASA, DOE, International Fermi LAT Collaboration

It also rolls so that solar panels are kept pointed at the Sun for power, and the axis of its orbit precesses like a top, making a complete rotation once every 54 days.



Centered on the LAT instrument’s field of view, the plot spans 180 degrees and follows Vela’s position from August 2008 through August 2010.

Precession of a gyroscope

via apod