Space Variable Objects Monitor

Using synergy between space and ground instruments, the mission has these scientific objectives:{{cite web|url=http://www.svom.fr/en/|title=The SVOM mission, a new generation GRB mission|publisher=Commissariat à l'énergie atomique et aux énergies alternatives|access-date=26 October 2015}}

• Permit the detection of all known types of Gamma-ray bursts (GRB)
• Provide fast, reliable GRB positions
• Measure the broadband spectral shape of the prompt emission (from visible to MeV)
• Measure the temporal properties of the prompt emission (from visible to MeV)
• Quickly identify the afterglows of detected GRBs at X-ray and optical wavelengths, including those which are highly redshifted (z>6)
• Measure the broadband spectral shape of the early and late afterglow (from visible to X-rays)
• Measure the temporal evolution of the early and late afterglow (from visible to X-rays)

The selected orbit is circular with an altitude of {{cvt|600|km}} and an inclination angle of 30° with a precession period of 60 days.{{cite web |url=http://www.svom.fr/en/|title=SVOM: The scientific payload|publisher=Commissariat à l'énergie atomique et aux énergies alternatives|access-date=26 October 2015}} The payload is composed of the following four main instruments:{{cite web|url=http://missions-scientifiques.cnes.fr/SVOM/GP_satellite.htm|title=SVOM Satellite |publisher=CNES|date=2014|access-date=26 October 2015}}

File:ECLAIRs coded mask.jpg

; ECLAIRs

: ECLAIRs is a wide-field (~2 sr) coded mask camera with a mask transparency of 40% and a {{cvt|1024|cm2}} detection plane coupled to a data processing unit, so-called UGTS, which is in charge of locating GRBs in near real time image and rate triggers.{{Cite conference |editor1-last=Takahashi |editor1-first=Tadayuki |editor2-last=Den Herder |editor2-first=Jan-Willem A. |editor3-last=Bautz |editor3-first=Mark |last1=Godet |first1=O. |last2=Nasser |first2=G. |last3=Atteia |first3=Jonathan |last4=Cordier |first4=B. |last5=Mandrou |first5=P. |date=July 2014 |title=The x-/Gamma-ray camera ECLAIRs for the gamma-ray burst mission SVOM |conference=Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray |publisher=SPIE |volume=9144 |page=914424 |arxiv=1406.7759 |bibcode=2014SPIE.9144E..24G |doi=10.1117/12.2055507 |display-authors=et al |s2cid=119248306 }} The trigger system of the coded-mask telescope ECLAIRs onboard SVOM images the sky in the 4-120 keV energy range, in order to detect and localize GRB in its 2 sr-wide field of view. The low-energy threshold of ECLAIRs is well suited for the detection of highly red-shifted GRB.{{Cite conference |last1=Schanne |first1=S. |last2=Paul |first2=J. |last3=Wei |first3=J. |last4=Zhang |first4=S.-N. |last5=Basa |first5=S. |last6=Atteia |first6=J.-L. |last7=Barret |first7=D. |last8=Claret |first8=A. |last9=Cordier |first9=B. |last10=Daigne |first10=F. |last11=Evans |first11=P. |last12=Fraser |first12=G. |last13=Godet |first13=O. |last14=Götz |first14=D. |last15=Mandrou |first15=P. |last16=Osborne |first16=J. |date=13–17 October 2009 |title=The future Gamma-Ray Burst Mission SVOM |conference=The Extreme Sky: Sampling the Universe Above 10 keV |location=Otranto, Italy |arxiv=1005.5008}} ECLAIRs is expected to detect ~200 GRBs of all types during the nominal 3 year mission lifetime. To reach a 4 keV low-energy threshold, the ECLAIRs detection plane is paved with 6400 4×4 mm² and 1 mm-thick Schottky CdTe detectors. The detectors are grouped by 32, in 8x4 matrices read by a low-noise ASIC, forming elementary modules called XRDPIX.

; Gamma-ray Burst Monitor (GRM)

: A gamma-ray non-imaging spectrometer (GRM), sensitive in the 50 keV to 5 MeV domain, will extend the prompt emission energy coverage. GRB alerts are sent in real-time to the ground observers community.

; Microchannel X-ray Telescope (MXT)

: A spacecraft slew is performed in order to place the GRB within the narrow fields of view of two instruments - a soft X-ray telescope (MXT) and a visible-band telescope (VT), to refine the GRB position and study the early phases of the GRB afterglow.{{Cite conference |last1=Gotz |first1=D. |last2=Paul |first2=J. |last3=Basa |first3=S. |last4=Wei |first4=J. |last5=Zhang |first5=S. N. |last6=Atteia |first6=J.-L. |last7=Barret |first7=D. |last8=Cordier |first8=B. |last9=Claret |first9=A. |last10=Deng |first10=J. |last11=Fan |first11=X. |last12=Hu |first12=J. Y. |last13=Huang |first13=M. |last14=Mandrou |first14=P. |last15=Mereghetti |first15=S. |last16=Qiu |first16=Y. |last17=Wu |first17=B. |date=20–23 October 2008 |title=SVOM: a new mission for Gamma-Ray Burst Studies |conference=6th Huntsville Symposium on Gamma-Ray Bursts |location=Huntsville, Alabama |publisher=American Institute of Physics |arxiv=0906.4195 |bibcode=2009AIPC.1133...25G |doi=10.1063/1.3155898 |display-authors=et al }} MXT uses lobster-eye optics that will give it a wide field of view.{{Cite web|url=https://www.svom.eu/en/delivery-of-the-mxt-telescope-optics/|title=Delivery of the MXT telescope optics – Svom}}

; Visible Telescope (VT)

: A {{cvt|45|cm}} visible telescope operating from 400 to 950 nm, with a FOV of 21 × 21 arcminutes. It will reach a sensitivity of about 23 magnitudes, in the R band, in a 300 seconds exposure time, at 5 seconds.{{Clarify|reason=What does 5 seconds refer to if the exposure time is 300s?|date=November 2024}}

The ground segment includes a set of three ground-based dedicated instruments – two robotic Ground Follow-up Telescopes (GFT) and an optical monitor, Ground Wide Angle Camera (GWAC) – which will complement the space borne instruments. A large fraction of GRB will have redshift determinations, an observing strategy optimized to facilitate follow-up observations by large ground-based spectroscopic telescopes.

A key elements of the SVOM mission are the Ground Wide Angle Cameras (GWACs) and the Ground Follow-up Telescopes (GFTs).{{cite web|url=http://www.svom.fr/en/|title=SVOM: The ground segment |publisher=Commissariat à l'énergie atomique et aux énergies alternatives|access-date=26 October 2015}}{{cite web|url=https://svom.cnes.fr/en/SVOM/GP_segment_sol.htm|title=Ground Segment |date=24 April 2015 |publisher=CNES|access-date=26 October 2015}}

; Ground Wide Angle Cameras (GWACs)

: The GWACs, an array of wide FoV optical cameras operating in the optical domain, will permit a systematic study of the visible emission during and before the prompt high-energy emission. It will cover a field of view of about 8000 deg², with a sensitivity of about 15 magnitudes at 5 seconds (under the full Moon condition), in the V band and with a 15 seconds exposure time. It will monitor continuously the field covered by ECLAIRs in order to observe the visible emissions of more than 20% of the events, at least 5 minutes before and 15 minutes after the GRB trigger.

; Ground Follow-up Telescopes (GFT)

: The GFTs, two robotic 1-meter class telescopes (one managed by France, another one by China), will point automatically their field-of view towards the space-given error box within tens of seconds after the alert reception and will provide panchromatic follow-up (visible to near-infrared). They will contribute to the improvement of the link between the scientific payload and the largest telescopes by measuring the celestial coordinates with an accuracy better than 0.5{{''}}, and by providing an estimate of its photometric redshift in less than 5 minutes after the beginning of the observations. This data will be available to the scientific community through an alert message. Evenly placed on the Earth (one in South America in a place to be defined, the other one in China), they will be in a position to start the research of the GRB optical emission immediately after the alert reception in more than 40% of the cases.

{{Portal|Astronomy|Spaceflight}}

• List of gamma-ray bursts
• List of X-ray space telescopes

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{{Commons category|SVOM}}

• [http://www.svom.fr/en/ SVOM website] by Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
• [https://svom.cnes.fr/en/SVOM/index.htm SVOM website] by CNES

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