Update 25 June

Update 25 June

Today was one of the best days yet for GLAST.  Overnight, the LAT high voltage was turned on, completing the instrument turn-on sequence more than a day early.  Around sunrise, the LAT started physics runs.  This was our first chance to use the LAT to detect high-energy particles from space — and everything just worked beautifully!  Data were shipped to the ISOC at SLAC (see previous posts) and processed quickly.  Just having the data chain work end-to-end without significant problems was a great accomplishment, and it was thanks to all the detailed rehearsals.  LAT scientists around the world then examined the data, and so far everything looks even better than we expected.  Initial estimates of backgrounds indicate they are at a very manageable level.  There are some minor details in the instrument diagnostic data (this tells us how the instrument itself is working) we don’t yet understand, but we will soon.  More about all this in future posts.  There are now many days of work ahead to tune, configure, and calibrate the instrument, and we are well on our way.

This evening, the GBM turned on its high voltage, and it is also now operational!  After about a week of testing and calibrations, the GBM should be ready to start looking for gamma-ray bursts.  More about this as well in posts over the next few days.  Everything looks good, and the GBM team is also very happy. 

Overnight, the observatory will transition from pointed mode (always looking in one direction) to sky survey mode: every two orbits (three hours) the LAT will sweep its field of view across the entire sky.  This is the primary science observing mode, so it is an important mode for tuning the instruments.

Here’s an interesting site to check if you’d like to know where your favorite satellite is at the moment.

We had a small celebration in the Mission Operations Center toward the end of the day.  We didn’t pause long, though, since there is much more work to do before we can start routine science operations.  However, none of us thought we’d be this far along so quickly.