eXTP Accomodation Study Hong Bin, Zhang Long Institute of Spacecraft System Engineering. CAST Oct 27th, 2015

Outline The XTP Remarks11 The eXTP Requirements22 WFM Configuration33 LAD Configuration44 Discussion and Summary55

XTP Instruments High energy X-ray Focusing Array (5 Units) FL=5500mm Low energy X-ray Focusing Array (10 Units) FL=4500mm High energy Collimating Array (2 Units) or LAD (20 Units, 1.5m 2 ) Wide Field Camera (1 Unit) 1.The XTP Remarks

Launch Vehicles Lauch VehiclesLM-3C Lauch SiteXichang Payload Fairing4200F The 4200F fairing has an external diameter of 4,200 mm, a total height of 9,381 mm,is the biggest one in the series of the LM-3 family. 1.The XTP Remarks

Observation Mode a.The –X axis points to the specific targets in the inertial space ； b.The sun vector is constrainted in XOZ plane and in a obtuse angle with the +Z axis ； c.The normal vector of solar array shall be parallelled to the sun vector by rotating the solar array ； d.Altitude maneuver is performed to observation continually according to the user‘s plan of observation. 1.The XTP Remarks targets Suns

XTP System Parameters ItemRequirement (XTP) Mass3500 kg Power Budget3200 W (include short-term power consumption) Orbit550km, 28°(14°backup) Observation ModePointing Observation Accuracy of attitude pointing < 0.01° (3σ) Accuracy of attitude measurement < 0.002° (3σ) Attitude stabilization 0.005°/s (3σ) 1’/500s (3σ) Attitude maneuver<10min in +/-30degree, 20 times/year Life time5 years 1.The XTP Remarks

eXTP Instruments High energy X-ray Focusing Array(5 Units) FL= 4500mm Low energy X-ray Focusing Array (10 Units) FL= 4500mm LAD (40 Units——4 panles 3 m 2 ) Wide Field Monitor (2 pairs) 2.The eXTP Requirements

eXTP Anticipate Parameters ItemeXTP Anticipate Parameters Mass3700 kg Power Budget3600 W (include short-term power consumption) Orbit 550km 28°(14° ？ ) Observation ModePointing Observation Accuracy of attitude pointing < 0.01° (3σ) Accuracy of attitude measurement < 0.002° (3σ) Attitude stabilization 0.005°/s (3σ) 1’/500s (3σ) Attitude maneuver<10min in +/-30degree, 20 times/year Life time5 years It’s impossible to decrease the orbit inclination(less than 14°). 2.The eXTP Requirements

First, the WFM is placed on the optical bench where is blank; Part of the cameras would be obstructed by the sunshield In place B ; No space enough to mount the camera due to the two star trackers in place A and C, and the fairing is another reasons; So there is only one place could mount the WFM; 3. WFM Configuration(2 pairs) WFM Configuration （ 2 pairs ） B C A D √

place D is an ideal place to mount the WFM because the tube could act as the sunshield which could protect the masks and detectors from the solar radiation; Two anti-sun camera pairs are mounted on place D, inclined by 0°, 60°; With respect to the optical axis (+15°, -15° ， +30°) 3. WFM Configuration(2 pairs) WFM Sunshield-By Satellite Structure

on the ground LAD Configuration （ 40 modules ） Two panels per side; Each panels assembled 10 modules; Folded on the ground; Stretched out in two opposite direction In orbit; The temperature could be under control if we could protect the detector from the solar radiation, according to the results of thermal analysis. The sunshield is required. 4. LAD Configuration(4 panels) In orbit

LAD Sunshield Dimensions Sunshield acreage requirement ： 40 m 2 (all optics in the shadow) ; The temperature of the LAD could be controlled at -20 ℃ ~-10 ℃ ; The atmospheric drag is increased, so it needs more than 40kg fuel to maintain the orbit height. 4. LAD Configuration(4 panels) More details talked by Mr Li Xiao ！

LAD Structure and Mechanical structure Supports the 40 Units LAD module ; Made of CFRP; Permit the alignment of the LAD module; Stiff enough to avoid deformations due to accelerations and thermal stresses. mechanical Withstand launch loads; Release the panels in obit ; deploy and latch in the final position. 4. LAD Configuration(4 panels) More details talked by Mr Li Xiao ！

It’s impossible to decrease the orbit inclination ( less than 14°). It’s feasible to mount 2 pairs WFM and 40 LAD Module. The sunshield is required to fufill temperature requirements of the LAD. With the sunshield, the temperature of LAD could be controlled at -20 ℃ ~-10 ℃. The sunshield would increase the atmospheric drag, more fuel is required to maintain the orbit height. 5. Dicussion and Summary

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