The Universe is home to numerous exotic and beautiful phenomena, some of which can generate almost inconceivable amounts of energy. Supermassive black holes, merging neutron stars, streams of hot gas moving close to the speed of light ... these are but a few of the marvels that generate gamma-ray radiation, the most energetic form of radiation, billions of times more energetic than the type of light visible to our eyes. What is happening to produce this much energy? What happens to the surrounding environment near these phenomena? How will studying these energetic objects add to our understanding of the very nature of the Universe and how it behaves?
The Fermi Gamma-ray Space Telescope, formerly GLAST, is opening this high-energy world to exploration and helping us answer these questions. With Fermi, astronomers at long last have a superior tool to study how black holes, notorious for pulling matter in, can accelerate jets of gas outward at fantastic speeds. Physicists are able to study subatomic particles at energies far greater than those seen in ground-based particle accelerators. And cosmologists are gaining valuable information about the birth and early evolution of the Universe.
For this unique endeavor, one that brings together the astrophysics and particle physics communities, NASA has teamed up with the U.S. Department of Energy and institutions in France, Germany, Japan, Italy and Sweden. General Dynamics was chosen to build the spacecraft. Fermi was launched June 11, 2008 at 12:05 pm EDT.
Both instruments on Fermi have been returned to operational status and are actively collecting science data. For the LAT, this data will be used to monitor performance as the instrument returns to normal operating temperatures. GBM has returned to full functionality.
Fermi was commanded out of sun-point mode earlier today (3/27). It is now oriented at a 50 degree rock angle (towards the northern hemisphere) with respect to the zenith. Operations at a fixed rock angle will continue while spacecraft performance is monitored. We plan to start bringing the instruments back online over the next week or so - GBM first and then the LAT. We will post updates on the status of the observatory as the recovery proceeds.
At 5:11 UT on March 16, Fermi encountered an issue with the solar array drive that caused the observatory to go into safe hold. In this mode, the instruments are powered off, and thus science data taking has stopped. Initial investigation suggests that one of the solar panels is stuck.
Investigation into the cause of the anomaly is ongoing and will continue for some time. We are exploring options to resume some science operations with a fixed solar panel which would run while the anomaly investigations are ongoing. The team is planning to start a return to science ops next week, to run in parallel with the ongoing engineering investigation.