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Abstract: This chapter reports the recent progress on the space astronomy missions of China, including the following missions: currently operating in orbit, e.g., DAMPE, Insight-HXMT, GECAM, PolarLight, GRID and Lobster-eye X-ray Satellite; approved and under development for launch in the next a couple of years, e.g., SVOM and EP; planned experiments to be onboard China’s Space Station in the next several years, e.g., CSST, HERD, POLAR-2, DIXE and LyRIC; candidate missions that have passed the first round of review of Strategy Priority Program on space science (III) of the Chinese Academy of Sciences, e.g., eXTP, DAMPE-2, Earth 2.0, DSL and CHES.
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Key words:
- Space science /
- Space astronomy /
- Satellite /
- Space station
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Figure 13. Current optimizations of LyRIC: the optical design (upper left), the inside view (upper right); major specifications (lower left); the outlook (lower right). Taken from Ref. [29]
Table 1. Summary of space astronomy missions/projects of China. Phase A-feasibility; Phase B-preliminary definition/design; Phase C-detailed definition/design; Phase D-qualification and flight model
Name of project Launch time Status Category DAMPE 17 Dec. 2015 In orbit 1 Insight-HXMT 15 Jun. 2017 In orbit 1 GECAM 9 Dec. 2020 In orbit 1 PolarLight 29 Oct. 2018 In orbit 1 GRID 29 Oct. 2018 (GRID-01)
6 Nov. 2020 (GRID-02)
27 Feb. 2022 (GRID-03 b and GRID-04)In orbit 1 Lobster-eye X-ray Satellite 2020 Jul. 25 In orbit 1 SVOM 2023 Phase D 2 EP 2023 Phase D 2 CSST 2023/2024 Phase C 2 HERD 2027 Phase B 3 POLAR-2 2024 (European payload)
2025 (Chinese payload)Early Phase D (European payload)
Phase B (Chinese payload)3 DIXE – Phase A 3 LyRIC 2025+ Phase A 3 eXTP 2027 Phase B 4 DAMPE-2 2025–2026 (Suggested) – 4 Earth2.0 TBD – 4 DSL 2026 Phase A 4 CHES TBD – 4 Table 2. Major characteristics of the Insight-HXMT
Detectors LE: SCD, 384 cm2
ME: Si-PIN, 952 cm2
HE: NaI/CsI, 5000 cm2Energy range LE: 1–15 keV
ME: 5–30 keV
HE: 20–250 keVTime resolution HE: 25 μs
ME: 280 μs
LE: 1 msEnergy resolution LE: 2.5% @ 6 keV
ME: 14% @ 20 keV
HE: 19% @ 60 keVField of view of one module LE: 6°×1.6°; 6°×4°, 60°×3°, blind
ME: 4°×1°, 4°×4°, blind
HE: 5.7°×1.1°, 5.7°×5.7°, blindAngular resolution (20σ source) < 5' Source location (20σ source) <1' Sensitivity (3σ, in 105 s) 0.5 mCrab (only statistical uncertainties included) Orbit Altitude: 550 km Attitude Inclination: 43°
Three-axis stabilizedControl precision: 0.1° Measurement accuracy: 0.01° Data rate LE: 3 Mbit·s–1
ME: 3 Mbit·s
HE: 300 kbit·sPayload mass 1000 kg Nominal mission lifetime 4 years Working mode Scan, pointing, GRB Table 3. Specifications of GECAM
Parameters Values Notes Orbit 600 km, 29° – Life time 3 years Goal: 5 years GRD energy range 15 keV–5 MeV – Field of view 60% all-sky For GECAM-B only Burst sensitivity <2×10–8 erg·cm–2·s–1 20 s, 10–1000 keV Burst localization accuracy <1° (1σ stat.) Flux:1×10–6 erg·cm–2·s–1, 10 s Absolute timing accuracy <3 μs – Relative timing accuracy 0.1 μs Between detectors Time latency of
trigger data60 s For the first BDS message Note 1 erg=10–7 J Table 4. Specifications of PolarLight
Energy range 2–8 keV Energy resolution 19% @ 6 keV Field of view 2.3° FWHM or 5.7° FWZR Gas mixture pure DME at 0.8 atm, 1 cm thick Window 100 μm beryllium GEM 100 μm pitch and 100 μm thick ASIC 50 μm pitch Modulation factor 0.42 @ 3.74 keV Weight 580 g Power 2.2 W Size 1 U (about 10 cm × 10 cm × 10 cm) Table 5. Specifications of GRID
Energy range 20 keV–2 MeV Energy resolution 20% FWHM @ 662 keV Field of view 2π Scintillator Ce-doped Gd3(Al,Ga)5O12 (GAGG) SiPM J-60035 manufactured by SensL Payload size 0.5 U (about 10 cm × 10 cm × 5 cm) Table 6. Key parameters of “Lobster-eye X-ray Satellite”
Dimension 750 mm×500 mm×320 mm
(2840 mm with solar panel)Power 30 W Orbit LEO Optics 2×2 MPO
(f = 375 mm, A = 4 cm×4 cm)Detector CCD
1024 pixel×1024 pixelField-of-view 2°(with detector) Angular resolution <0.2° Energy range 1–6 keV (in-orbit) Energy resolution <200 eV Table 7. Specifications of WXT and FXT
Parameters WXT FXT Number of modules 12 2 Telescope optic Lobster-eye MPO Wolter-I Detector CMOS CCD Field of view $ \geqslant $3600 square degrees $ \geqslant $38′(diameter) Focal length/mm) 375 1600 Effective area @1.2 keV·cm–2 2.7 300 (each module) Spatial resolution (1 keV) 5′(FWHM) 30″ (HPD) Bandpass/keV 0.5–4 0.3–10 E-resolution @1.25 keV (eV) 170 120 Sensitivity/(erg·s–1·cm–2) 1×10–11 @ 1 ks 1×10–14 @10 ks Note 1 erg=10–7 J Table 8. HERD main specifications
Energy range (e/γ) 10 GeV–100 TeV (e)
0.5 GeV–100 TeV (γ)Energy range (CR) 30 GeV–PeV Angular resolution 0.1° @10 GeV Charge resolution 0.1– 0.3 c.u Energy resolution (e) 1%@200 GeV Energy resolution (p) 20%@100 GeV–PeV e/p separation 106 G.F. (e) >3 m2·sr@200 GeV G.F. (p) >2 m2·sr@100 TeV Table 9. Main anticipated technical performances of POLAR-2
Characteristics Instrument HPD LPD BSD Detector sensitive material Plastic scintillator bars array DME or Xenon mixture LaBr3 crystal Energy range 30–800 keV 2–10 keV (potentially can be extended to
30 keV depending on the gas)10–2000 keV Detection area 2000 cm2 ≥290 cm2 For each module≥40 cm2 Field of view 50% sky 90°×90° 50% sky Energy resolution – ≤25%@5.9 keV ≤18%@59.5 keV Dimensions 590×664×700 mm3 600×600×710 mm3 Table 10. Key parameters of the preliminary payload design
Parameter Value Notes Lower energy/keV 0.1 Goal Upper energy/keV 5 Point of optimization Energy resolution/eV < 6 Goal: 2 eV at 1 keV Field of view/(º)2 100 With mechanical collimator Effective area/cm2 > 0.5 Goal: 1 cm2 Grasp/[cm2·(º)2] > 50 Goal: 100 cm2·(º)2 Power/W 800 Peak: 1000 W Mass/kg 300 Goal: < 200 kg Table 11. Instrument configuration and key specifications
Instrument SFA LAD PFA WFM Configuration 9 telescopes 40 modules 4 telescopes 6 cameras Optics or Collimator Wolter-I, Nickel
F = 5.25 mcapillary-plate collimators Wolter-I, Nickel
F = 5.25 mCoded mask Detector 19-pixel Silicon
Drift Det. (SDD)SDD Gas Pixel Detector (GPD) SDD Energy range 0.5–10 keV 2–30 keV 2–8 keV 2–50 keV Effective area
or FoV≥0.6 m2@1–2 keV
0.4 m2 @ 6 keV3.0 m2 at 8 keV 500 cm2 @ 2 keV
300 cm2 @ 3 keVFoV ≥ 3.1 sr Energy resolution (FWHM) 180 eV @ 6 keV 260 eV @ 6 keV 25% @ 6 keV ≤500 eV@6 keV Time resolution 10 µs 10 µs 10 µs 10 µs Remarks Unprecedented effective area in the soft X-ray
energy rangeHigh throughput;
effective area is a
factor of 5–10 larger
than any previous
missionAbout 5 times the area
of IXPE, X-ray polar. Pathfinder by NASA; Min. Detectable Polarization about 3%
in 2–8 keV rangePeak sensitivity: 1 Crab in 1 s and 5 mCrab in 50 ks (5σ source).Point source localization ≤ 1′ Table 12. Summary of CHES
Science case Habitable exoplanets orbiting nearby stars Science objectives To discover habitable Earths about nearby solar-type stars
To conduct a comprehensive survey and census on the nearby planetary systems
Extended: cosmology, dark matter and black holesOverview Spacecraft at L2 for 5 years
Optical telescope (500–900 nm);
Micro-arcsecond astrometry (1 μas)
Point and stare strategy to enable relative astrometryWhat makes CHES unique Ultra-high-precision relative astrometry simply reachable from space: 0.3 μas (habitable
Earths about the stars at 10 pc)
To obtain true masses and orbital architecture (inclinations, etc.) of habitable-zone terrestrial
planets and to conduct the census and characterization of nearby planetary systems
Extended: Measurements of orbits and distances to reveal the interiors of neutron, etcPrimary observational targets closeby F, G, K stellar systems (100 stars with 10 pc)
Extended: ultra-faint dwarf galaxies, neutron stars in X-ray binaries, etc.Scientific Payload Coaxial three-reflection TMA system
Primary mirror: D = 1.2 m diameter
Long focal length: f = 36 m
FoV: 0.44°×0.44°, with 6 to 8 reference stars; focal plane with 81 scientific CMOS
detectors (4000×4000, ≥50 frame·s–1)
Nyquist sampling of the PSF
Metrology calibration of the Focal Plane Array (FPA): relative positions of pixels at the micro-pixel level for each detector, geometrical parameters of FPASpacecraft Spacecraft dry mass with margin: 1,558 kg. Launch Mass: 2930 kg, fuel mass (990 kg + 382 kg)
Attitude Control System: pointing accuracy of 0.07 arcsec, pointing stability of 0.0036 arcsec/0.02 sec
Propulsion system: orbital maneuver engines: 490 N+12×10 N,attitude control thrusters:
12×(1–50 µN) + 12×20 mN
Thermal Control System: working temperature: 20±5° and temperature stability of 45 mK
for payload; working temperature: –15 to +45℃ for other instruments
Telecommand: X-band, communication rate: 20 Mbit·s–1Launcher and operations CZ-3 C: GTO (200 km× 35958 km). Orbital maneuver to Halo orbit at L2. Launch in 2025
Nominal mission: 5 years. Launch site: Xichang -
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