The small mission A-STAR (All-Sky Transient Astrophysics Reporter) aims to locate the
X-ray counterparts to ALIGO and other gravitational wave detector sources, to study the
poorly-understood low luminosity gamma-ray bursts, and to find a wide variety of transient
high-energy source types, A-STAR will survey the entire available sky twice per 24 hours.
The payload consists of a coded mask instrument, Owl, operating in the novel low energy
band 4−150 keV, and a sensitive wide-field focussing soft X-ray instrument, Lobster,
working over 0.15−5 keV. A-STAR will trigger on ~100 GRBs/yr, rapidly
distributing their locations.