Space-Based Multi-band Astronomical Variable Objects Monitor (SVOM)

The space-based multi-band astronomical variable objects monitor (SVOM) is a Sino-French space mission dedicated to the study of gamma-ray bursts (GRBs). The mission is designed to detect, localize, and follow-up GRBs and other high-energy transients. The satellite is equipped with two wide-field gamma-ray instruments for detecting transients and two narrow-field telescopes operating at X-ray and optical wavelengths for follow-up observations. It is complemented by a dedicated ground segment with a set of wide-field optical cameras for prompt optical emission and two 1-meter class follow-up telescopes. A VHF communication system is built to downlink SVOM alerts to the ground. The Beidou short-message communication system is used for upload commands quickly for ToO observation requirements, and used as the supplement for the VHF downlink system. The pointing strategy of the satellite has been optimized to maximize the detection of GRBs located in the night hemisphere. This strategy enables the study of the optical emission in the first minutes after a GRB with robotic observatories and the early spectroscopy of the optical afterglow with large telescopes to measure its redshift. The satellite is planned to be launched in 2023.