next space vlbi mission, astro-g (vsop-2) and its spectrum management astro-g project (jaxa) y....
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NEXT SPACE VLBI MISSION, ASTRO-G (VSOP-2)
ANDITS SPECTRUM MANAGEMENT
ASTRO-G Project (JAXA)
Y. Murata ( JAXA)
HALCA and VSOP (1997-2005)Highly Advanced Laboratory for Communications and Astronomy
VLBI Space Observatory Programme
3C345
VLBA VSOP
Launch: Feb. 12, 1997 Apogee 21,000km Perigee 560 km 380 minutes period
Observing bands:
1.6, 5.0 GHz
(22 GHz)
Phase Link & Data Transmission:
Downlink 128 Mbps QPSK
@ 14.2 GHz
Uplink CW @ 15.3 GHz
TT&C: S-band with LGA
Plasma torus
VSOP with HALCA
• The first space VLBI imaging mission
• Studied AGN environment and jet physics– Structure and kinematics of jet
in AGN– Absorption near the core and
study of torus structure– Existence of high brightness
temperature sources
Also Pulsars, X-ray binaries, OH masers
Beamwidth 100 Rs at 5 GHz for M87
Plasma Torus in absorption
4-years jet monitoring
3C273
Jet Structure
1928+738
ASTRO-G (VSOP-2) – VLBI Space Observatory Programme – 2
10 times higher sensitivity
10 times higher frequency observation
10 times higher resolution with ~ 40 arcseconds
Observing bands 8, 22, 43 GHz
Dual polarization
Phase-referencing capability
The next generation Space VLBI (SVLBI) mission following the VSOP mission
9.26 m Antenna for
Radio Astronomy
Mass 1200kg (Nominal)
1 Gbps Data Downlink
Compared to VSOP:
Astrophysics with ASTRO-G (VSOP-2)
Generate VLBI array with Ground Radio Telescopes.
Magnetic fields of galaxies
Jets from the accretion disks around black holes
Radio galaxies
Quasars
Observe astronomical objects with the highest resolution.
Lobanov, A.P. 2003, SKA Memo 38
Comparison of Telescope Resolutions
VSOP
CurrentTelescopes
VERA
Radio IROptical
UV X γ
1mas
1SKA
ASTRO-G(VSOP-2)
Comparison ofASTRO-G/VSOP-2 and HALCA/VSOP
• More information on fine structure and magnetic field from AGN jets and cores– Higher resolution with polarization capability
• Higher sensitivity– With 2 polarization, 8 times wider bandwidth (only continuum sources)
• High agility attitude control system using control moment gyros– Improved calibration capability (ASTRO-G can observe calibrators, HALCA could not)– Phase-referencing observations enabled
Allows weaker source detection by extending integration time and astrometry observations
• High accuracy navigation using onboard GPSR and SLRRequired for phase-referencing
ASTRO-G Satellite Configuration• 9.3-m offset Cassegrain antenna with module structures
– Light weight– gimbal adjuster– focusing system
– Mass (wet) 1200Kg– Power 2000W
第22号科学衛星 SOLAR-B ASTRO-G Configuration
Orbit Apogee Height 25,000 km Perogee Height 1,000 km Inclination 31° Orbit Period 7.5 h
Solar Paddle
rSolar Paddle天体方向
副鏡
主鏡
9.6 m
Ka Ant for VLBI Link
Satelite Size Mass 1,200 kg Power 2,000 W
Observation Target Satellite For VLBI• 9 meter Deployable Antenna for 43GHz• Cooled LNA ( 30 K )• 1 Gbps Down Link• Phase Compensation Observation Target Switching (3deg manoeuvre in 15 sec) Orbit Determnation with 10 cm Accuracy
Solar Paddle
Sub Reflector
Main Reflector
Rocket & Orbit
• Launch Rocket is H2A – Launch epoch; FY 2012– Single or Shared Launch is not decided now.
• ASTRO-G Orbit (HALCA)– Apogee Height: 25,000 km (21,300 km)– Perigee Height: 1,000 km (560 km)– Inclination 31°(31 °)– Orbit Period 7.5 hours (6.3 h)
Key Technology: Large Deployable Antenna
Module-type offset-Cassegrain antenna(use ETS-VIII deployment mechanism)
Mesh + Tension Truss
Need higher accuracy moduleOffset-cassegrain antenna
HALCA ( 1997 )
ETS-VIII ( Dec. 2006 )
Large Deployable Antennas (2/2)
Seven Modules (Stow / Deployment)
Azimuthal Hoop Cable & Radial Rib. Cable Network
XY
Development Module (2003)
Improve Surface accuracy (0.4mmrms)ETS-VIII 2GHz, ASTRO-G 43GHz
ASTRO-G Observing System
ASTRO-G tracking station
H Maser
Data Storage
VLBI Data DownlinkFrequency 37-38 GHzBit Rate 1 GbpsModulation QPSKTX-Power 25 W
High Gain AntennaDiameter: 80cm
Data StorageCapacity 4 TB / 8 hours
Phase Transfer UplinkFrequency 40 GHzNo ModulationTX-Power 100mW
Phase Comparison
Ground Link Station Diameter >10mOver 3 stations
ASTRO-G
Precision Oribt Determination
GPS
Precision LaserReflectors
Postioning Accuracy<10 cm
Ground Laser Stations
ASTRO-G25,000x1,000km
GPS20,000km
1,2 GPS Sats @ Apogee.Many GPS Sats @ Perigee
Astro-G Operation and Data flow
Ground telescopes
Tracking
Station
Satellite Operation
Correlator
Data Analysis
SchedulingScheduling
• Note: very similar to HALCA operation and data flow
Current Status of ASTRO-G
System Definition Review 19 Mar. 2007PROJECT Official START 1 Jul, 2007Basic Design of the satellite system (April 2007 – March 2008) Structure and Thermal model analysis is on going. Thermal deformation, Fix of the interfaces.Preliminary Design Review #1 (February – June 2008) 3 month delay For instruments need to start detailed design earlier. Main Reflector, Structures, Cryostat, Ka-HGA Preliminary Design Review #2 (March 2009) Other instrumentsCritical Design Review (March 2010) 6 month delay to the last schedule
Basic DesignSub-reflector
Antenna Tower
Bus System Solar ArrayPaddle
Ka HGA
Main Reflector
International Matters
• Meetings– Tracking station meetings
• #4 @ Greenbank, Aug. 2007• #5 @ Sagamihara, Dec. 2007
– VSOP-2 symposium (Dec 3-7, 2007 @ Sagamihara) • 135 participants. Half from outside of Japan (13 countries)
– VSOP-2 Science Meeting (14-16, 2008 @ Bonn)
• Proposals– SAMURAI proposal (submitted in Jan. 2008)
• Proposal to NASA Mission of opportunity for US VSOP-2 supports (Tracking station, VLBA, JPL project office and navigation. See. NRAO report)
– European Proposals FP7 SPIRIT • ESA Nationally Led proposal (Tracking station, SVLBI use of GRT, Correlat
ors).
International Matters (2)• VISC-2 Formation
– VISC-2(VSOP-2 International Science Council) We form VISC-2 to make consensus related to scientific operations of VSOP-2. Possible VISC-2 fu
nctions are selection of KSPs, scientific scheduling, decisions of international relations, scientific operations. (Finally decided in the first VISC-2 meeting in Bonn in May, 2008)
– pre-meeting • Dec. 2007 @ Sagamihara• April, 2009 @Telecon• May, 2009 First F-F Meeting in Bonn
– Members: • Ex-officio(ISAS/JAXA): H.Saito, M.Tsuboi • Institutional members (12):ISAS(1): Y.Murata (co-chair), NAOJ(1): M.Inoue, JVN(1): K.Fujisawa EAVN (1): H.Kobayashi, KVN/KASI (1): S.-H.Cho, NRAO(1): J.Ulvestad( JPL(1): D.Murphy ), JIVE(1): L.Gurvits, EVN(1): A.Zensus (co-chair)OAN(1): R.Bachiller, ATNF(1): P.Edwards, GVWG(1): J.Romney (NRAO)• At-large members (3): D. Gabuzda (Univ. Collage Cork, Ireland), S.Kameno (Kagoshima Univ.), + Astrome
try person (TBD)• VISC2 adviser (2): D.Jauncey, H.Hirabayashi• Liaison (1): R.Schilizzi (ISPO (International SKA Project Office))• Secretary(1): Y.Hagiwara (NAOJ)
ASTRO-G radio frequency usage
Ground Radio Telescopes Ground Tracking StationsCommanding
Station
40 GHz 37-38 GHz
3-4 stations in the world.10-20 radio telescopes around the world.
JAXA commanding
station
Frequency Management Activities
1. Frequency Selection:• Observing bands, Space VLBI (Up/downlink data), TT&C
2. SFCG (Space Frequency Coordination Group)• Coordination among space agencies• Information for ASTRO-G was submitted in September, 2007
3. ITU-R SG7• General SVLBI (Space VLBI) coordination have already done by US (JPL)
group at WP7B. Recommendation ITU-R SA.1344 : SVLBI system description “Preferred frequency bands and bandwidths for Space VLBI” Up 40-40.5 GHz, Down 37-38 GHz• Sharing studies in 37-38 GHz band are going now.• Observing band protection in radio astronomy bands in 22/43 GHz is not cl
ear now.
ASTRO-G frequency SelectionObserving band:
8.0 – 8.8 GHz, 20.6 – 22.6 GHz, 41.0 – 43.0 GHz
ASTRO-G (VSOP-2) Specifications (1/2)
Status of the frequency sharing study for ASTRO-G in 37-38 GHz downlink
•Space VLBI (SVLBI) system : Recommendation ITU-R SA.1344.
•Drafting Group 3 in ITU-R SG-7 Working Party 7B (WP7B)
•Sharing study to Lunar systems (SRS) and FSS.
•WP7B chairman's report (Document 7B/168-E) was released last February
•VSOP-2/ASTRO-G parameters are in Table 3.1 in Annex 8 to document 7B/168-E. But some of the parameters in this table have already updated. Difference of the table is as follows:
ASTRO-G (VSOP-2) – VLBI Space Observatory Programme – 2
10 times higher sensitivity
10 times higher frequency observation
10 times higher resolution with ~ 40 arcseconds
Observing bands 8, 22, 43 GHz
Dual polarization
Phase-referencing capability
The next generation Space VLBI (SVLBI) mission following the VSOP mission
9.26 m Antenna for
Radio Astronomy
Mass 1200kg (Nominal)
1 Gbps Data Downlink
Compared to VSOP:
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