The GLAST (Gamma Ray Large Area Space Telescope) was sent into low-Earth orbit on June 11, 2008. Several months prior to Launch, NASA commissioned a series of interviews with project scientists, as well as a series of animations illustrating what those scientists described.
At the bottom of the GLAST tower array is a one and a half ton sensor called the calorimeter. This device is responsible for reporting the amount of energy released by the inbound gamma photons by converting them into a shower of positrons, electrons, and more gamma photons. By counting the number of particles in this shower, scientists are able to measure the amount of energy released by the gamma-producing event.
Click here to see the full interview sequence in which these animations are featured.