The GSFC MOXE Information Page

The MOnitoring X-ray Experiment (MOXE) is an X-ray all-sky monitor to be launched on the Russian Spectrum-X-Gamma satellite. It will monitor several hundred X-ray sources on a daily basis, and due to its four day high-earth orbit will be the first instrument to monitor most of the X-ray sky most of the time. MOXE will serve as an alarm, to alert users of more sensitive instruments on Russia's giant high energy astrophysics observatory and of other instruments to transient activity. MOXE will also produce long time baseline light curves of many sources which will be virtually free of gaps due to Earth occultation. MOXE consists of an array of 6 X-ray pinhole detectors, sensitive from 2 to 25 keV, which views 4 pi steradians (except for a 20 X 80 square degree patch which obscures the Sun). The pinhole apertures of 0.625 X 2.556 square cm imply an angular resolution of 2.4 X 9.7 square degrees(FWHM on-axis). The flight instrument will mass approximately 118 kg and draw 38 Watts. For a non-focussing all-sky instrument that is limited by sky background, the limiting sensitivity is a function only of detector area. MOXE will, for a 24 hrs exposure, have a sensitivity of approximately 2 mCrab. MOXE distinguishes itself with respect to other all-sky monitors in its high duty cycle, thus having unprecendented sensitivity to transient phenomena with time scales between minutes and hours.