March 9, 2017

Satellite

SVOM is a minisatellite supplied by CNSA. The payload is composed of the following four main instruments:

  • the ECLAIRs large field telescope (French supply)
    An experimental instrument designed to detect and study gamma-ray bursts (GRBs) in the X-ray and low-energy gamma-ray band, the ECLAIRs telescope is a key element of the SVOM payload. This instrument includes the following sub-systems:
    • TXG (Telescope X and Gamma), a large wide-field X- and gamma-ray telescope (2 sr) with acoded mask to detect the GRBs in the 4-50 keV range and to observe their prompt emission in the 4 - 150 keV range
    • the management and data processing electronic module called (UGTS Unit for detector manaGement, Triggering and Scientific processing)

  • MXT narrow-field telescope (Microchannel X-ray Telescope) (supplied by France)
    This telescope is sensitive in the so-called "soft" X-ray spectral domain (0.2 keV to 10.0 keV) with a field of view of about 1° able to locate the position of GRBs in the sky with an accuracy better than 2 arcminutes.

  • GRM gamma detector (Gamma-Ray burst Monitor) (supplied by China)
    Set of three "phoswich" (phosphor sandwich) detectors, based on two scintillator planes joined together for which scintillations are collected by the same photomultiplier tube. The GRM set designed to measure the light curve and spectral parameters of the prompt emission of bursts (already detected by ECLAIRs) in the hard X-ray and low-energy gamma-ray range (30 keV to 5 MeV).

  • VT narrow field telescope (Visible Telescope) (supplied by China)
    Narrow-field telescope (21 x 21 arcminutes) designed to observe the early afterglow in the visible (400 - 650 nm) and the near-infrared (650 - 950 nm) until the K band. For GRB observation, the platform can direct itself automatically in the direction of the burst indicated by ECLAIRs.


Where instruments are located on the satellite

The SVOM satellite will be put in an orbit at an altitude of 600 km with a slight inclination to avoid disturbances in the polar areas. When a GRB is detected by the ECLAIRs instrument, the satellite will be able to reposition itself very quickly (a few minutes) to complete the observations in the soft X-ray domain with the MXT and in the visible domain with the VT. The information must also be transmitted to the ground in less than one minute to cue dedicated robotic telescopes as well as large ground telescopes.

Animation showing the SVOM mission principle.

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