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ASTROD and ASTROD I: DeepSpace Laser Ranging Missions ASTROD: ASTRODYNAMICAL SPACE TEST OF RELATIVITY USING OPTICAL DEVICES ASTROD I --- A FIRST STEP OF ASTRODYNAMICAL SPACE TEST OF RELATIVITY USING OPTICAL DEVICES presented by Wei-Tou Ni, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 1 Current ASTROD Collaborators ZARM, Bremen Hansjörg Dittus Claus Lämmerzahl Stephan Theil Imperial College Henrique Araújo Diana Shaul Timothy Sumner CERGA J-F Mangin Étienne Samain ONERA Pierre Touboul Humboldt U, Berlin Achim Peters 2006.04. 21. Purple Mountain Obs, CAS U Düsseldorf Wei-Tou Ni, Gang Bao, Stephan Schiller Guangyu Li, H-Y Li, Andreas Wicht Max-Planck, Gårching A. Pulido Patón, J. Shi, F. Wang, Y. Xia, Jun Yan Albrecht Rüdiger Technical U, Dresden CAST, Li Wang, Hou, Zhang, ... Sergei Klioner IP, CAS, Y-X Nie, Z. Wei Soffel U Missouri-Columbia Yunnan Obs, CAS, Y.Xiong ITP, CAS, Y-Z Zhang Sergei Kopeikin Nanjing U Tianyi Huang IAA, RAS George Krasinsky Tsing Hua U Sachie Shiomi Nanjing A & A U H. Wang Elena Pitjeva Nanyang U, Singapore Nanjing N U, X. Wu, C. Xu H S & T U, Ze-Bing Zhou H-C Yeh ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 2 ASTRODynamical Space Test of Relativity using Optical Devices S/C 2 S/C 1 Laser Ranging Launch Position Inner Orbit Sun Outer Orbit Earth Orbit point .EarthL1(800 days after launch) 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 3 OBJECTIVE ASTROD Testing relativistic gravity and the fundamental laws of spacetime with 5 order-of-magnitude improvement in sensitivity; Improving the sensitivity in the 5 µHz - 5 mHz low frequency gravitational-wave detection by several orders of magnitude as in LISA but shifted toward lower frequencies; Revolutionize the astrodynamics with laser ranging in the solar system, increasing the sensitivity of solar, planetary and asteroid parameter determination by 3-4 orders of magnitude. 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 4 ASTROD I: Two-Way Interferometric and Pulse Laser Ranging between Spacecraft and Ground Laser Station 0.8 Testing relativistic gravity with 3-order-ofmagnitude improvement in sensitivity; Astrodynamics & solar-system parameter determination improved by 1-3 orders of magnitude; Improving gravitational-wave detection compared to radio Doppler tracking (Auxiliary goal). 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions (B) 0.6 0.4 0.2 Y Axis (AU) 0.0 Sun -0.2 -0.4 -0.6 -0.8 Venus Mercury spacecraft -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 ASTROD study team X axis (AU) 5 0.6 0.8 1.0 1993 Laser Astrodynamics was proposed to study the relativistic gravity and to explore the solar system in 2nd William Fairbank Conference (Hong Kong) and in the International workshop on Gravitation and Fifth Force (Seoul). ASTROD mission concept – 7th Marcel Grossmann (Stanford, 1994) and 31st COSPAR (Birmingham, 1996) Ġ /G and solar-system mass loss measurement (Seoul, 1996) G-wave sensitivity studied; Mini-ASTROD and Super-ASTROD proposed (1st TAMA Meeting, Tokyo, 1997) Lab and Mission Concept Studies (1993-2000) 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 6 International Collaboration Period 2000: ASTROD proposal submitted to ESA F2/F3 call (2000) 2001: 1st International ASTROD School and Symposium held in Beijing; Mini-ASTROD study began 2002: Mini-ASTROD (ASTROD I) workshop, Nanjing 2004: German proposal for a German-China ASTROD study collaboration approved 2005: 2nd International ASTROD Symposium of these combined meetings (June 2-3, Bremen, Germany) 2004-2005: ESA-China Space Workshops (1st &2nd, Noordwijk & Shanghai), potential collaboration discussed 2006: Collaboration Proposal Applied to Sino-German Center; 3rd ASTROD Symposium (July 14-16, Beijing) before COSPAR (July 16-23) in Beijing May- September, 2006: Joint ASTROD I proposal to be submitted to ESA call for Cosmic Vision proposals 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 7 Gravitational wave strain sensitivity for ASTROD compared to LISA 1E-15 LISA Bender extension LISA, 1 yr int. time S/N=5 1E-16 Gravitational Wave Strain ASTROD, 1 yr int. time, S/N=5 1E-17 1E-18 1E-19 1E-20 1E-21 1E-22 1E-23 1E-24 1E-25 1.00E-06 1.00E-05 1.00E-04 1.00E-03 1.00E-02 1.00E-01 Frequency (Hz) 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 8 Outgoing Laser beam Telescope Optical readout beam Incoming Laser beam Dummy telescope 2006.04. 21. Proof mass Large gap ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 9 Orbit Simulation Assumptions (1) The uncertainty due to the imprecision of the ranging devices: 1 ps one way (Gaussian) (2) Unknown acceleration due to the imperfections of the spacecraft drag-free system: 10-17m/s2 & change direction randomly every 4 hr (~104s) [This is equivalent to (10-17m/s2) (104s)1/2 = 10-15m/s2(Hz) ½ at 10-4Hz] 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 10 Error (s) An error simulation for 2015 launching orbit 2.0x10 -11 1.5x10 -11 1.0x10 -11 5.0x10 -12 Outer 0.0 -5.0x10 -12 -1.0x10 -11 -1.5x10 -11 -2.0x10 -11 -2.5x10 -11 0 2006.04. 21. 500 1000 1500 2000 Time (day) ASTROD & ASTROD I: Deep-Space Laser Ranging Missions 2500 3000 ASTROD study team 11 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 12 Gaussian Fits & Propagation of Errors 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 13 Simulation for 3000 days 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 14 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 15 Expected Mass-Loss Rate of the Sun Mechanism Fractional Rate -------------------------------------------------Solar EM Radiation 7 Х 10-14/yr Solar Wind ~ 10-14/yr Solar Neutrino ~ 2Х 10-15/yr Solar Axion ~ 10-15/yr -------------------------------------------------2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 16 Aimed accuracy of PPN space parameter γ for various ongoing / proposed experiments. The types of experiments are given in the parentheses. 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 17 Crucial Technology 100 fW weaklight phase locking Design and development of sunlight shield system Design and development of dragfree system 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 18 The Results for 20 pW Power Beam Error Signal 2006.04. 21. X: 20 s/div Y: 10 mV/div Locked ASTROD & ASTROD I: Deep-Space Laser Ranging Missions X: 50 ms/div Y: 10 mV/div ASTROD study team 19 Experemental Results Low Power Beam Intensity (measured using oscilloscope) High Power Beam Intensity (mW) Low Power Intensity Measured by Lock-in Amplifier r.m.s. Error signal Vrms(mV ) r.m.s Phase error(rad) Phase-locking time 20 nW 2 nW 200 pW 20 pW 2 pW 2 2 0.2 0.2 0.2 153 ~247 pW N/A N/A 20.9 nW 2.15 nW 2.01 2.06 2.29 2.03 2.70 0.0286 0.057 0.2 0.16 0.29 Longer than observation duration Longer than observation duration >2 hours >2 hours 1.5 presented by Wei-Tou Ni, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing mins 20 Weaklight Phase Locking Requirement: phase locking to 100 fW weak light Achieved: phase locking of 2 pW weak light with 200 µW local oscillator With pre-stabilization of lasers, improving on the balanced photodetection and lowering of the electronic circuit noise, the intensity goal should be readily be achieved This part of challenge should be focussed on offset phase locking, frequency-tracking and modulation-demodulation to make it mature experimental technique (also important for deep space communication) Weak light phase locking experiment re-started at PMO 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 21 Drag-free System R & D Consists of a high-precision accelerometer/inertial sensor to detect non-drag-free motions and microthruster system to do the feedback to keep the spacecraft drag-free Looking for collaboration with ONERA and Trento University to learn the R & D they have for accelerometer/inertial sensor Collaboration with ZARM, Bremen University for feedback control and end-to-end spacecraft model Collaboration with Imperial College on charge control of the proof mass 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 22 Design of Sunlight Shield System Sun shutter Narrow band filter FADOF filter 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 23 Design of Sunlight Shield System The sunlight shield system consists of a narrow-band interference filter, a FADOF (Faraday Anomalous Dispersion Optical Filter) filter, and a shutter The narrow-band interference filter reflects most of the Sun light directly to space The bandwidth of the FADOF filter can be 0.65 GHz With the shutter, the Sun light should be less than 1 % of the laser light at the photodetector 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 24 Solar oscillation modes 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 25 BISON network observations 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 26 μ 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 27 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 28 1-year amplitude modulation of solar oscillation for ASTROD A joint/dedicated mission are under investigation 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 29 ASTROD GOAL Testing relativistic gravity and the fundamental laws of spacetime with 5 order-of-magnitude improvement in sensitivity; Improving the sensitivity in the 5 µHz - 5 mHz low frequency gravitational-wave detection by several orders of magnitude as in LISA but shifted toward lower frequencies; Revolutionize the astrodynamics with laser ranging in the solar system, increasing the sensitivity of solar, planetary and asteroid parameter determination by 3-4 orders of magnitude. Chance to detect solar g-mode oscillations 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 30 ASTROD I 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 31 ASTROD I: Two-Way Interferometric and Pulse Laser Ranging between Spacecraft and Ground Laser Station 0.8 Testing relativistic gravity with 3-order-ofmagnitude improvement in sensitivity; Astrodynamics & solar-system parameter determination improved by 1-3 orders of magnitude; Improving gravitational-wave detection compared to radio Doppler tracking (Auxiliary goal). 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions (B) 0.6 0.4 0.2 Y Axis (AU) 0.0 Sun -0.2 -0.4 -0.6 -0.8 Venus Mercury spacecraft -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 ASTROD study team X axis (AU) 32 0.6 0.8 1.0 Typical Launch Trajectory of ASTROD I 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 33 Spacecraft Trajectory 0.8 (B) 0.6 0.4 Y Axis (AU) 0.2 0.0 Sun -0.2 -0.4 -0.6 -0.8 Venus Mercury spacecraft -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 X axis (AU) 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 34 Spacecraft-Venus Distance 1.6 (B) Distance between spacecraft and Venus 1.4 Distance (AU) 1.2 1.0 0.8 0.6 0.4 0.2 0.0 (111.75 day, 34904.2 km) -0.2 0 200 (336.24 day, 24640.6 km) 400 600 800 Mission Day 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 35 Orbit Description Launch via low earth transfer orbit to solar orbit with orbit period 300 days First encounter with Venus at 118 days after launch; orbit period changed to 225 days (Venus orbit period) Second encounter with Venus at 336 days after launch; orbit period changed to 165 days Opposition to the Sun: shortly after 370 days, 718 days and 1066 days 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 36 Apparent Angles during 2 Solar Oppositions 0.4 0.3 0.2 0.1 Angle Z (Deg) 0.0 Sun -0.1 -0.2 719.7 day 717.1 day -0.3 -0.4 369.1 day 371.3 day -0.5 -0.6 -0.7 -0.8 -0.6 1st closest approach nd 2 closest approach o 0.377 (1.51R¡ó )@ 370.2 day 0.315 (1.26R¡ó )@ 718.4 day o -0.4 -0.2 0.0 0.2 0.4 0.6 Angle Y (Deg) 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 37 Shapiro Time Delays Shapiro Time Delay (£gsec) 120 111.4 £gsec 107.2 £gsec 100 80 60 40 20 0 0 200 400 600 800 Mission Day 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 38 Orbit Simulation Assumptions (1) The uncertainty due to the imprecision of the ranging devices: 10 ps one way (Gaussian) (2) Unknown acceleration due to the imperfections of the spacecraft drag-free system: 10-15m/s2 & change direction randomly every 4 hr (~104s) [This is equivalent to (10-15m/s2) (104s)1/2 = 10-13m/s2(Hz) ½ at 10-4Hz] 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 39 3 Sets of Simulated Data (Total: 50 sets) 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 40 Uncertainties of Determining Gamma and Beta as a function of Epoch 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 41 Uncertainties of Determining Solar Quadrupole Parameter J2 as a function of Epoch 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 42 Gaussian Fit of 50 Determinations of Relativistic Parameters 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 43 Orbit Simulation Results Determine the relativistic parameter γ to 10-7. Determine the relativistic parameter β to 10-7 and others with improvement. Improve the solar quadrupole moment parameter J2 determination by one order of magnitude, i.e., to 10-9. Ġ /G to 10-13/yr 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 44 Schematic Diagram of the ASTROD I Spacecraft Black Surface FEEP Power Unit Optical Comb Clock CW Lasers Optical Cavity Thermal Control Electronics Telescope TIPO Pulse Laser Power Unit Black Surface 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions FEEP ASTROD study team 45 Schematic Diagram of the ASTROD I Spacecraft: (i) Cylindrical spacecraft with diameter 2.5m, height 2m and cylindrical surface covered with solar panels, (ii) In orbit, the cylindrical axis is perpendicular to the orbit plane with the telescope pointing toward the ground laser station. The effective area to receive sunlight is about 5m2 and can generate over 500 W of power. (iii) The total mass of spacecraft is 300-350 kg. That of payload is 100-120 kg. (iv) Science data rate is 500 bps. The telemetry rate is 5 kbps for about 9 hours in two days. 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 46 Payload (1) Laser systems for interferometric and pulse ranging (i) 2 (plus 1 spare) diode-pumped Nd:YAG laser (wavelength 1.064 m, output power 1 W) with a Fabry-Perot reference cavity: 1 laser locked to the Fabry-Perot cavity, the other laser pre-stabilized by this laser and phase-locked to the incoming weak light. (ii) 1 (plus 1 spare) pulsed Nd:YAG laser with transponding system for transponding back the incoming laser pulse from ground laser stations. (2) Quadrant photodiode detector (3) 380-500 mm diameter f/1 Cassegrain telescope (transmit/receive), /10 outgoing wavefront quality 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 47 Payload (4) Sunlight Shield System (5) Drag-free proof mass (reference mirror can be separate): 50 35 35 mm3 rectangular parallelepiped; Au-Pt alloy of extremely low magnetic suceptibility (<10-5); Ti-housing at vacuum 10-5 Pa ; six-degree-offreedom capacity sensing. (6) Cesium clock (7) Optical comb 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 48 One Way Laser ranging Time Transfer by Laser Link TIPO Etienne Samain, Patrick Vrancken OCA, Gemini 2130 route de l’Observatoire 06460 Caussols, FRANCE Philippe Guillemot CNES Av Edouard Belin 31400 Toulouse, FRANCE Cheng Zhou (PMO) is in OCA studying and working on 3 ps event timer 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team Ground Station for the ASTROD I Mission at Yunnan Observatory ◆ Introduction of Yunnan Observatory 1.2m Telescope & Its Laser Ranging System ◆ Key Requirements of Ground Station for the Mission ◆ Telescope Requirement: Pointing and Tracking Accuracy ◆ Atmospheric Turbulence Effects on Laser Ranging ◆ F. Song of Yunnan Observatory is collaborating with Y. Luo of PMO to study the laser acquisition and pointahead presented by Wei-Tou Ni, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 50 ◆ Yunnan Observatory 1.2 mTelescope Its Laser Ranging System Coordinates: Latitude 25.0299 N Longitude 102. 7972 E Elevation 1991.83 m 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 51 Optics Design for ASTROD I 2006.04. 21. Albrecht Ruediger and Haitao Wang : Bremen talk 2005, and ASTROD2006 talk ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 52 ASTROD I Drag-free Control Hongying Li from PMO is in Bremen studying and working with Stephan Theil, Hansjoerg Dittus, and Claus Laemmerzahl to work out a preliminary drag-free control for ASTROD I. Paper to be presented in the forthcoming COSPAR general assembly. 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 53 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 54 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 55 Theoretical Foundations Chongming Xu: 2nd order light deflection Kopeikin, Klioner, Soffel Tianyi Huang: time scales Peng Dong, Yi Xie: 2nd order Post-Newtonian Approximation and Astrodynamics 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 56 Acceleration disturbances and requirements for ASTROD I Sachie Shiomi and Wei-Tou Ni Center for Gravitation and Cosmology Dept. of Phys., Tsing-Hua Univ., Hsinchu presented by Wei-Tou Ni, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 57 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 58 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 59 ASTROD I: Charging Simulation & Disturbances Gang Bao(1,2), Diana N A Shaul(3), Henrique M Araujo(3), Wei-Tou Ni(1,2), Tim J Sumner(3) & Lei Liu(1) (1)Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (2)National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (3)Department of Physics, Imperial College London, London, SW7 2BZ, UK 2nd presented by Wei-Tou Ni, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 60 International ASTROD Symposium, 2-3 June 2005, ZARM, Bremen, Germany GEANT4 Charging Simulation Charging for Protons Q(t) = 26.2 +e/s 180 160 Charge(+e) 140 120 100 80 60 40 20 0 -20 0 2 4 6 8 Time(s) 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 61 Launcher and Mission Lifetime Launcher: Long March IV B (CZ-4B) Mission Lifetime: 3 years (nominal) 8 years (extended) 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 62 OUTLOOK ASTROD I Testing relativistic gravity and the fundamental laws of spacetime with three-order-of-magnitude improvement in sensitivity; gamma to 10-7 or better, beta to 10-7, J2 to 10-9, asteroid masses to 10-3 fraction Improving the sensitivity in the 5 µHz - 5 mHz low frequency gravitational-wave detection by several times; Initiating the revolution of astrodynamics with laser ranging in the solar system, increasing the sensitivity of solar, planetary and asteroid parameter determination by 1-3 orders of magnitude. Optimistic date of launch: 2015 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 63 Spacecraft and Mission Analysis Study 2006.04. 21. Li Wang, Hou, Zhang, ... from China Academy of Space Technology are working on it ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 64 Thank you! 2006.04. 21. ASTROD & ASTROD I: Deep-Space Laser Ranging Missions ASTROD study team 65