1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) DECIGO Pathfinder Seiji Kawamura, Takashi Nakamura, Kimio Tsubono, Takahiro Tanaka, Ikkoh Funaki, Naoki Seto, Kenji Numata, Shuichi Sato, Nobuyuki Kanda, Takeshi Takashima, Kunihito Ioka, Kazuhiro Agatsuma, Tomotada Akutsu, Tomomi Akutsu, Koh-suke Aoyanagi, Koji Arai, Yuta Arase, Akito Araya, Hideki Asada, Yoichi Aso, Takeshi Chiba, Toshikazu Ebisuzaki, Motohiro Enoki, Yoshiharu Eriguchi, Masa-Katsu Fujimoto, Ryuichi Fujita, Mitsuhiro Fukushima, Toshifumi Futamase, Katsuhiko Ganzu, Tomohiro Harada, Tatsuaki Hashimoto, Kazuhiro Hayama, Wataru Hikida, Yoshiaki Himemoto, Hisashi Hirabayashi, Takashi Hiramatsu, Feng-Lei Hong, Hideyuki Horisawa, Mizuhiko Hosokawa, Kiyotomo Ichiki, Takeshi Ikegami, Kaiki T. Inoue, Koji Ishidoshiro, Hideki Ishihara, Takehiko Ishikawa, Hideharu Ishizaki, Hiroyuki Ito, Yousuke Itoh, Shogo Kamagasako, Nobuki Kawashima, Fumiko Kawazoe, Hiroyuki Kirihara, Naoko Kishimoto, Kenta Kiuchi, Shiho Kobayashi, Kazunori Kohri, Hiroyuki Koizumi, Yasufumi Kojima, Keiko Kokeyama, Wataru Kokuyama, Kei Kotake, Yoshihide Kozai, Hideaki Kudoh, Hiroo Kunimori, Hitoshi Kuninaka, Kazuaki Kuroda, Kei-ichi Maeda, Hideo Matsuhara, Yasushi Mino, Osamu Miyakawa, Shinji Miyoki, Mutsuko Y. Morimoto, Tomoko Morioka, Toshiyuki Morisawa, Shigenori Moriwaki, Shinji Mukohyama, Mitsuru Musha, Shigeo Nagano, Isao Naito, Noriyasu Nakagawa, Kouji Nakamura, Hiroyuki Nakano, Kenichi Nakao, Shinichi Nakasuka, Yoshinori Nakayama, Erina Nishida, Kazutaka Nishiyama, Atsushi Nishizawa, Yoshito Niwa, Masatake Ohashi, Naoko Ohishi, Masashi Ohkawa, Akira Okutomi, Kouji Onozato, Kenichi Oohara, Norichika Sago, Motoyuki Saijo, Masaaki Sakagami, Shin-ichiro Sakai, Shihori Sakata, Misao Sasaki, Takashi Sato, Masaru Shibata, Hisaaki Shinkai, Kentaro Somiya, Hajime Sotani, Naoshi Sugiyama, Yudai Suwa, Hideyuki Tagoshi, Kakeru Takahashi, Keitaro Takahashi, Tadayuki Takahashi, Hirotaka Takahashi, Ryuichi Takahashi, Ryutaro Takahashi, Takamori Akiteru, Tadashi Takano, Keisuke Taniguchi, Atsushi Taruya, Hiroyuki Tashiro, Mitsuru Tokuda, Masao Tokunari, Morio Toyoshima, Shinji Tsujikawa, Yoshiki Tsunesada, Ken-ichi Ueda, Masayoshi Utashima, Hiroshi Yamakawa, Kazuhiro Yamamoto, Toshitaka Yamazaki, Jun'ichi Yokoyama, Chul-Moon Yoo, Shijun Yoshida, Taizoh Yoshino Masaki Ando Department of Physics, the University of Tokyo

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 2 Overview Overview Mission payload Mission payload Noise estimation Noise estimation Current status Current status Summary Summary

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 3 Overview Overview

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 4 DECIGO Roadmap Figure: S.Kawamura Mission Objective Test of key technologies GW observation at low frequencies Detection of GW w/ minimum spec. Test FP cavity between S/C Full GW astronomy Design 1 S/C 1 Fabry-Perot arm 3 S/C 1 interferometer 3 S/C, 3 interferometer 3 or 4 units DICIGO Pathfinder (DPF) Pre-DECIGO DECIGO R&D Fabrication R&D Fabrication R&D Fabrication

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 5 DECIGO Pathfinder DECIGO Pathfinder (DPF) One small satellite (Weight: ~350kg, Orbit: around the Earth) 30cm Fabry-Perot cavity formed by free masses Stabilized laser source Drag-free control system Local Sensor Actuator Thruster Scientific observation Low-frequency (0.1-1Hz) GWs Intermediate-mass BHs at the Galactic center Gravity distribution of Earth Test and demonstration for DECIGO Laser stabilization system Control of Fabry-Perot interferometer Drag-free control system

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 6 DPF Satellite Size : 950mm cube Weight : 200kg SAP : 940W Battery: 50AH Downlink : 2Mpbs DR: 1GByte 3N Thrusters x 4 Stabilized Laser Interferometer Module Thruster Control Unit Solar Paddle Interfererometer Control Unit Housing Control Unit Mission Thrusters Central Processing Unit Bus Thrusters Satellite Bus (‘Standard bus’ system) DPF Payload Size : 950mm cube Weight : 150kg Power : 120W Data Rate: 800kbps Mission thruster x12 Power Supply SpW Comm.

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 7 DPF Mission Outline Orbit: Low-Earth (Altitude 500km), Sun-synchronous orbit (dusk-dawn) Launcher: Single launch by M-V follow-on (solid rocket booster under development) PBS (Post-Boost stage) for fine orbit insertion Mission Lifetime: 1 year (nominal) 500km DPF Attitude Control: Gravity-gradient stab. Drag-free control with mission thrusters

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 8 Mission payload Mission payload

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 9 DPF Payload Fabry-Perot interferometer Finesse : 100 Length : 30cm Test mass : 1kg Signal extraction by PDH Laser source Yb:YAG laser (1030nm) Power : 25mW Freq. stab. by Iodine cell Drag-free control Local sensor signal  Feedback to mission thrusters Weight : ~150 kg Size : ~95 cm cube Upper half of the satellite

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 10 Stabilized laser Laser source Yb:YAG laser (1030nm) Power : 25mW Freq. stab. by Iodine absorption line  0.5 Hz/Hz 1/2 (at 0.1Hz) Comparable stability with that by a reference cavity at 0.1Hz Advantage of I 2 stabilization Less affected by environment Easier ground-base tests Moderate vibration isolation No vacuum system Disadvantages Less experience Narrow absorption line at 515nm Musha-san and Nagano-san’s talks tomorrow

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 11 Main interferometer Test-mass module Keeps a test inside Local sensor/actuator Launch-lock system Interferometer sensors for fine measurement Sato-san’s talk tomorrow Fabry-Perot interferometer Finesse : 100 Length : 30cm Test mass : ~1kg Signal extraction by PDH

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 12 Drag-free and attitude control Drag-free control for demonstration of control system suppression of external disturbances (solar radiation, air drag, …) Passive + Active stabilization Passive stabilization by gravity-gradient Mast (~30kg) attached for MOI adj. Active drag-free with 12 mission thrusters Satellite Bus Attitude control at initial phase and fail safe 3N thruster x4, Magnetic torquer x3 Solar sensor, Fiber gyroscope Requirement: m/Hz 1/2 (0.1Hz) for satellite disp. Mast Moriwaki-san’s talk tomorrow

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 13 DPF Sensitivity Satellite mass : 350kg, Area: 2m 2 Altitude: 500km Thruster noise: 0.1μN/Hz 1/2 Laser source : 1030nm, 25mW IFO length : 30cm Finesse : 100, Mirror mass : 1kg Q-factor : 10 5, Substrate: Fused Silica Temperature : 293K (Preliminary parameters)

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 14 DPF Targets Quasi-normal mode oscillation Binary inspiral of BHs Detectable with SNR~5 h ~ , f ~ 0.3 Hz Distance 10 kpc, m = 10 5 M sun h ~ , f ~ 4 Hz Distance 10kpc, m = 10 3 M sun Science target: Intermediate-mass BHs at GC KAGAYA

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 15 Noise estimation Noise estimation

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 16 Comparison with LPF LPF (LISA Pathfinder) DPF (DECIGO Pathfinder) Stabilized Laser Interferometer Module Thruster Control Unit Solar Paddle Interfererometer Control Unit Housing Control Unit Mission Thrusters Central Processing Unit Bus Thrusters Purpose Launch Weight Orbit Test Mass Laser source Interferometer Sensitivity Demonstration for LISA 2010 Dedicated launcher (Vega) 1,900 kg Halo orbit around L1 Drag-free attitude control Au-Pt alloy x2 Nd:YAG (1064nm) Mach-Zehnder 3x m/s 2 /Hz 1/2 (1mHz) Demonstration for DECIGO GW observation ~2012 Dedicated launcher (M-V follow-on) 350 kg SSO altitude 500km Drag-free attitude control TBD x2 Yb:YAG (1030nm) Fabry-Perot 1x m/s 2 /Hz 1/2 (0.1Hz)

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 17 Gravity-gradient noise Global gravity field model Public data obtained by GRACE Up to 2190 th-order coefficients in spherical harmonics Satellite velocity of 5km/sec Sufficiently small at 0.1Hz band m/s 2 acceleration at low freq. Satellite moves in the gravity field of Earth

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 18 Geomagnetic noise Public data at Esashi observatory 1 sample/min data  Extrapolate for higher frequency Two effect by geomagnetic field Geomagnetic field model IGRF-10 model (10 th generation of International Geomagnetic Reference Field) Altitude 500km Satellite velocity of 5km/sec Satellite self-field Effect of geomagnetic field: smaller than satellite self-field ~10 -7 T  noise level ~ 1.5 x m/s 2 /Hz 1/2 Magnetic-field noise Fluctuation in geomagnetic field Satellite motion in magnetic field

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 19 Noise sources Residual Gas Thermal radiation Magnetic field Laser freq. noise Force Acceleration Acceleration noiseDisplacement noise

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 20 Current Status Current Status

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 21 JAXA’s small satellite series Plan to launch 3 small satellites by the year 2015 using next-generation solid rocket booster Reduce time and cost by means of ‘Standard bus system’ Bus weight : ~ 200kg, Bus power : ~ 900W Downlink ~ 2Mbps, Data storage ~ 1GByte 3-axes attitude control SpaceWire-based data processing system 1 st mission (2011) : decided to be TOPS (Planetary science) 2 nd mission will be selected by 2009 March 5 Candidate missions ERG: Plasma and particle detector for geo-space investigation DPF: GW observation DIOS: X-ray telescope for dark baryon investigation Satellite for Magnet-plasma sail technology demonstration, … Image CG of TOPS (design has been changed now)

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 22 DPF Current status Laser frequency stabilization Mirror and its housing Micro thruster Drag-free control simulation Detailed design and noise investigation Submitting Phase-A proposal R&D for core technologies Proposing to launch in 2012 as 2 nd small satellite of JAXA 2005 Jan. Submit a proposal of small GW detector mission 2006 Nov. Submit a proposal of GW-detector satellite as DECIGO pathfinder (DPF) 2007 Aug. Selected as a Pre-Phase-A mission R&D costs funded Brief History Precursor: Small GW sensor (SWIM  ) to be launched in FY2008 SWIM fixed to SDS-1 satellite (July 11, 2008)

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 23 SWIM  Sensor module to demonstrate SpW communication Observation of gravitational waves (10 -7 /Hz 1/2 ) Monitor the satellite environment as accelerometers SWIM  : Tiny gravitational-wave detector Test mass Photo sensor Coil TAM: Torsion Antenna Module with free-falling test mass (Size : 80mm cube, Weight : ~500g) Reflective-type optical displacement sensor Separation to mass ~1mm Sensitivity ~ m/Hz 1/2 6 PSs to monitor mass motion ~47g Aluminum, Surface polished Small magnets for position control Used for test-mass position control Max current ~100mA 2 TAMs in the frame

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 24SWIM Small module for demonstration of SpaceWire-based data processing system SWIM (Space wire demonstration module) Total system Size : 220x200x180 Weight ~ 5.6 kg Power ~ 14 W One of main missions of SDS-1 CPU: HR5000 (64bit, 33MHz) System Memory: 2MB Flash Memory 4MB Burst SRAM 4MB Asynch. SRAM Data Recorder: 1GB SDRAM 1GB Flash Memory SpW: 3ch Comprised of SpaceCube2 and SWIM  SpaceCube2: Space-qualified Computer SWIM  : User Module Processor test board GW+Acc. sensor FPGA board DAC 16bit x 8 ch ADC 16bit x 4 ch  32 ch by MPX Torsion Antenna x2 ~47g test mass Size: 71 x 221 x 171 Weight: 1.9 kg Power: 7W Power ±15V, +5V SpW x2 for CMD/TLM Data Rate : 380kbps Size: 124 x 224 x 174 Weight: 3.5 kg Power: ~7W Power +28V RS422 for CMD/TLM GPS signal SDS-1 Bus System Current status: Fixed to SDS-1 CMD/TLM checked Photo by JAXA

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 25SDS-1 Small satellite for demonstration of space technologies SDS-1 (Small Demonstration Satellite) Size : 70x70x60cm,Weight : 100kg Power : >100W, Downlink : ~5kbps Orbit : SSO (~660km) Spin stabilization and 3-axis attitude control Mission Lifetime : ~Half year (nominal) Launch: FY2008 by H-IIA (piggy-back) SDS-1 and GOSAT (Press Release, November 4, 2008) Photo from Nainich Newspapser Web

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 26 Summary Summary

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 27Summary One small satellite (Weight: ~350kg, Orbit: around the Earth) 30cm Fabry-Perot cavity formed by free masses Stabilized laser source Drag-free control system Local Sensor Actuator Thruster Gravitational-wave observation Test and demonstration for DECIGO DECIGO Pathfinder: First precursor satellite for DECIGO Selected and funded as one of the candidates of JAXA’s small satellite missions Hoping to be launched in 2012 Observation band : 0.1Hz-1Hz Target : IBHs at the Galactic center

1st International LISA-DECIGO Workshop (November 12-13, 2008, JAXA/ISAS, Sagamihara, Japan) 28 End End