The UFFO (Ultra-Fast Flash Observatory) Pathfinder
  Hundreds of gamma-ray burst (GRB) UV-optical light curves have been measured
since the discovery of optical afterglows, however, even after nearly 5 years
of operation of the SWIFT observatory, only a handful of measurements have been
made soon (within a minute) after the gamma ray signal. This lack of early
observations fails to address burst physics at the short time scales associated
with burst events and progenitors. Because of this lack of sub-minute data, the
characteristics of the UV-optical light curve of short-hard type GRB and
rapid-rising GRB, which may account for ~30% of all GRB, remain practically
unknown. We have developed methods for reaching the sub-minute and the
sub-second timescales in a small spacecraft observatory appropriate for launch
on a microsatellite. Rather than slewing the entire spacecraft to aim the
UV-optical instrument at the GRB position, we use rapidly moving mirrors to
redirect our optical beam. Our collaboration has produced a unique MEMS
(microelectromechanical systems) micromirror array which can point and settle
on target in only 1 ms. This technology is proven, flying successfully as the
MTEL (MEMS Telescope for Extreme Lightning) on the Tatiana-2 Spacecraft in
September 2009 and as the KAMTEL on the International Space Station in April
2008. The sub-minute measurements of the UV-optical emission of dozens of GRB
each year will result in a more rigorous test of current internal shock models,
probe the extremes of bulk Lorentz factors, and provide the first early and
detailed measurements of fast-rise and short type GRB UV-optical light curves.
