  It has now been firmly established that the Universe is expanding at an
accelerated rate, driven by a presently unknown form of dark energy that
appears to dominate our Universe today. A dedicated satellite mission has been
designed to precisely map out the cosmological expansion history of the
Universe and thereby determine the properties of the dark energy. The
SuperNova/Acceleration Probe (SNAP) will study thousands of distant supernovae,
each with unprecedented precision, using a 2-meter aperture telescope with a
wide field, large-area optical-to-near-IR imager and high-throughput
spectrograph. SNAP can not only determine the amount of dark energy with high
precision, but test the nature of the dark energy by examining how its equation
of state evolves. The images produced by SNAP will have an unprecedented
combination of depth, solid-angle, angular resolution, and temporal sampling
and will provide a rich program of auxiliary science.
