1. Next Generation Space VLBI Project: VSOP-2 Inoue, M. 1, Nagai, H. 1, Asada, K. 2, Saito, H. 2, Tsuboi, M. 2, and the Next Generation Space VLBI Working Group 1,2 1: National Astronomical Obs. of Japan (NAOJ) 2: Institute of Space and Astronautical Science (ISAS) Extragalactic Jets, 21-24 May 2007, Girdwood, Alaska

2. 2 Abstract The second space VLBI Project (VSOP-2) has been approved, and just started construction of the satellite Astro-G in ISAS. Its key science targets are to investigate physical phenomena around massive black holes with its superb spatial resolutions up to 40 micro arcsec. By the dual polarization capability at all the three frequencies (8, 22, and 43 GHz), VSOP-2 is anticipated to be a powerful tool to investigate structure of the magnetic field in AGN jets to see the acceleration / collimation mechanism.

3. 3 HALCA and VSOP (1997-2006) VSOP: VLBI Space Observatory Programme HALCA: Highly Advanced Laboratory for Communications and Astronomy Obs. Frequencies at 1.6, 5, and 22 GHz 30,000 km baseline 360 micro arcsec resolution @ 5 GHz Launch: Feb. 12, 1997 Last command: Nov. 30, 2006 (3213 days after the launch) HALCA: 8-m Cassegrain antenna

4. VSOP-2 Science Targets The structure and magnetic fields of accretion disks in AGNs The mechanism of jet acceleration and collimation The motion of H 2 O masers in Galactic star forming regions Proto-stellar magnetospheres M87, M. Reid M87 simulation Takahashi et al. 2005 Uchida, Nakamura & Hirose 1999 ? ?

5. VSOP-2 Compared to VSOP; 10 times higher sensitivity. 10 times higher frequency 10 times higher resolution with 40 micro arcsec Observing bands: 8, 22, 43 GHz Dual polarization Phase-referencing capability 9-m offset Cassegrain antenna with 7-module structure

6. Orbit : Apogee 25,000 km Perigee 1,000 km Inclination 31deg Period 7.5 hours Phase Link & Data Transmission: Downlink 1 Gbps QPSK @ 37-38 GHz 2 IF x 512/256 Msps x 1/2bit Uplink CW @ 40 GHz 3-4 Ground tracking stations Observing bands: X: 8.0 - 8.8 GHz K: 20.6 - 22.6 GHz Q: 41.0 - 45.0 GHz Orbit & Data Transmission Parameters

7. 7 Financial Year (Apr-Mar) 2000 ～ 2005 200620072008200920102011 2012 ～ Spacecraft Development Phase Events Tracking Stations Ground Radio Telescopes. Basic DesignDetailed D.Manufacture and TestDesignConceptOperation Launch Ground Tracking Stations Developments Op. Test Phase -APhase -BPhase -CPhase -D Phase -E More than 3 years operation Pre Phase -A Selection of the science mission in ISAS Approval of project preparation △ Budget Request △ Selection of contractors △△ △ △ △ △ System I/F Fixed PMFM DesignFM ManuPre-ProjectWG phaseOperation I/F test Final Test Unit test FOp NEXT (X) Solar-sail (Jupiter) △ Review △ Project starts Design of PFM Structure Antenna, Obs.system Attidute control system Astro-G construction timeline

8. 8 Discussion and summary Construction of the satellite (Astro-G) for the VSOP-2 project has started, and discussion for international cooperation / collaboration is needed. –International science working group –Pre-launch observations / studies –Ground observing telescopes / VLBI networks –Tracking stations Powerful tool to investigate AGN jets –Very high spatial resolution –Dual polarization with wide frequency bands for magnetic field structure Please visit http://www.vsop.isas.jaxa.jp/vsop2/