1. Tiny torsion-type gravitational wave detector in space: SWIM  Wataru Kokuyama (University of Tokyo) on behalf of SWIM team

2. SWIM  : Technology Demonstration Module 80mm Sensor Module Test Mass 50mm - Torsion-type GW detector with noncontact-controlled test mass - A tiny module on a piggyback satellite - Position sensing with reflective infrared sensors - Actuation with coil-magnet pairs - Digital PID control implemented on FPGA - Space-qualified computer (SpC2) along with this box 120x180x220 mm 3, 3.5kg Demonstrate important technologies for DPF (FPGA-based feedback control, SpC2, etc.) SpC2

3. Photo of SDS-1 and other piggy-back satellites SDS-1 (equipped with SWIM  ) ©JAXA Not a CG! Jan. 23, 2009 Launch of SWIM 

4. SWIM  Operation - Operation time : Only 2-5 days/month! - # of Paths: 39 - Downloaded data: ~ 16.4MB Path: a comm. session with the satellite (~10min.) Statistics as of May 2010 - Successful test mass control (Total ~ 7 hours) - Noise spectrum of the sensor - Interesting behavior of test mass - Clock synchronization with GPS (6-digits accuracy) - In preparation for demonstration of GW observation Initial Check-out Lock Acquisition Calibration Noise Measurement (~Apr. 2009) (~May. 2009) Net power-on time : 46.7 hours in 16 months (~Mar. 2010) - send commands to the detector - typically 1 path/day

5. SWIM  Results: Lock Acquisition Vertical Control Start Horizontal Control Start

6. SWIM  Results: Noise Level Spin stabilized (Dec. 2009) 3-Axis, earth-oriented (Jan. 2010) 3-Axis, solar-oriented (Jan. 2010) Coupling with satellite spin (~50mHz)

7. SWIM  Results: Test mass as a Foucault pendulum Just after lock acquisition, test mass’s horizontal oscillation was observed. Center of mass motion 0.2mm Estimated spin rate ： 46.7 mHz Measured by Gyro ： 46.3 mHz in satellite-fixed coordinate ~2Hz ~50 mHz ~2Hz a Foucault pendulum on the spinning satellite SDS-1

8. Observation Plan with SWIM  Tokyo SWIM  Observation & data analysis demonstrations are planned. 2) Coincident observation with ground-based torsion-bar antenna at U.Tokyo / Kyoto U. - Detector in low-earth orbit moves around the earth in every 100min. http://www.astro.ucla.edu/~ghezgroup/gc/ journey/images/mw7b_gleason.jpg 1) GWs from the Galactic Center - Main target for DPF observations - SWIM  can be oriented at GC. Galactic center 10-digits worse sensitivity than DPF … Interesting analysis? (If there is, it can be applied to DPF.)