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SPICA
Mission profile
M class presentation
Paris, 1 December 2009
Advanced Studies and Technology
Preparation Division
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Overview of SPICA mission
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SPICA is a JAXA led mission scheduled for launch by 2018 (Phase A).
Medium and far IR observatory (5 – 210 um), with sky background limited
sensitivity via a cryogenically cooled telescope (3.5 m diameter, T < 6K).
Launcher vehicle is JAXA’s HII-B. Large halo orbit at SE-L2 (P ~ 180 days).
Nominal mission lifetime: 3 yr (5 yr goal).
Advanced Studies and Technology
Preparation Division
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Overview of SPICA mission
•
•
•
•
•
SPICA is a JAXA led mission scheduled for launch by 2018 (Phase A).
Medium and far IR observatory (5 – 210 um), with sky background limited
sensitivity via a cryogenically cooled telescope (3.5 m diameter, T < 6K).
Launcher vehicle is JAXA’s HII-B. Large halo orbit at SE-L2 (P ~ 180 days).
Nominal mission lifetime: 3 yr (5 yr goal).
Cryogenic model payload (cryogens free):
- Cryogenically cooled telescope assembly.
- MIRACLE (MIR camera & spectro-photometer).
- SAFARI (FIR imaging spectrometer).
- MIRHES (MIR High Resolution Spectrometer)
- MIRMES (MIR medium resolution spectrometer).
- SCI (MIR coronagraph).
- FPC (Focal Plane Camera dedicated to guidance).
- BLISS (FIR and sub-mm spectrometer – optional).
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The SPICA spacecraft
Configuration:
Cryogenic PLM supported by an octagonal SVM
via truss structure. ~ 4.4 m diameter, 7.5 m high.
Mass & power:
Total mass ~ 4 ton; total peak power ~ 2.4kW (EOL).
Attitude Control:
3-axis stabilised. RW’s. Focal Plane Camera (FPC)
in AOCS loop (to meet RPE < 7.5 mas/200s).
Thermal Control
System:
Passive cooling via coaxial Sun and thermal shields,
(reaching ~11K). Active cooling via 2-stage Stirling
and JT units (4.5 and 1.7 K stage).
Propulsion:
Monopropellant (blow down), propellant: 220 kg.
Data Handling:
Centralised DPU, MM > 48 Gbyte. Science data:
24h * 4 Mb/s = 350 Gbit/day.
TT&C:
X-Band (HGA, MGA for down-link), S-band (2 LGA
for up and down-link).
Ground segment: Usuda (JAXA), Cebreros or DS3 (4 hr/day).
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The SPICA spacecraft
Inner Shield
Middle Shield
Outer Shield
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The SPICA spacecraft
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European contribution to SPICA
1. SPICA Telescope Assembly:
ESA (Industrial assessment study, TAS-France and EADS Astrium France)
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M1, M2 and associated internal baffles.
M2 supporting structure, M2 mechanism and associated drive electronics.
Telescope Optical Bench.
Thermal HW (S/MLI, T sensors, heaters).
2. SAFARI instrument:
SPICA FIR Imaging Spectrometer (assessment study carried out by the
instrument consortium). ESA acting as official interface to JAXA.
3. GND segment contribution: provision of a ground station for 4hr/day
(subject of an internal ESA assessment).
4. European Science Centre: supporting the European scientists in
accessing the SPICA observatory (subject of an internal ESA assessment).
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SPICA Telescope Assembly (STA)
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SPICA Telescope Assembly (STA)
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Telescope assessment study
ASF
Main requirements:
• Diffraction limited performance at l = 5 um.
• Optical surfaces at T< 6K.
• Total mass (including design margins) < 700 kg.
• M2 structure based on 4-leg design (Coronagr. requirements).
• Interface to SVM via Telescope Optical Bench.
TAS
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Telescope assessment study
ASF
TAS
Main requirements:
• Diffraction limited performance at l = 5 um.
• Optical surfaces at T< 6K.
• Total mass (including design margins) < 700 kg.
• M2 structure based on 4-leg design (COR requirements).
• Interface to SVM via Telescope Optical Bench.
Baseline design:
• Ritchey-Chretien design (confirmed by both contractors).
• All ceramic design (mirrors and support structure) selected by
Astrium (SiC100) & TAS (HB-Cesic).
• Dedicated Instrument Optical Bench confirmed.
• Focus and tip/tilt mechanism (at M2).
• Detailed thermal and mechanical analysis performed.
• Optical surfaces at T < 6K; heat load ~ 20 mW at 4.5K.
• Thermo-elastic analysis shows compliance with WFE req.t.
• Overall feasibility confirmed by assessment study.
• STM + PFM. PFM delivery to JAXA by Q1-Q2/17.
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European contribution: SAFARI
Main requirements:
• Imaging and spectroscopy (continuous wavelength coverage
in the range 34 – 210 um).
• Photometric camera mode with R ~ 2 to 5.
• Spectroscopic mode with R = 2000 at 100 um.
• FOV = 2 x 2 arcmin2. Line sensitivity ~3E-19 W/m2 (48 um).
• Mass of cold assembly < 50 kg. Warm electronics < 30 kg.
• Flight Model delivery to JAXA required by end 2015.
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European contribution: SAFARI
Main requirements:
• Imaging and spectroscopy (continuous wavelength coverage
in the range 34 – 210 um).
• Photometric camera mode with R ~ 2 to 5.
• Spectroscopic mode with R = 2000 at 100 um.
• FOV = 2 x 2 arcmin2. Line sensitivity ~3E-19 W/m2 (48 um).
• Mass of cold assembly < 50 kg. Warm electronics < 30 kg.
• Flight Model delivery to JAXA required by end 2015.
Baseline design:
• Imaging Fourier Transform Spectrometer (34 - 210 um).
• 3x Focal Plane Arrays – Modified Mach-Zehnder interferom.
• ~ 6000 px. Selection of detector technology impacts design
(TES, KID, Si bolometers, Photo-cond. planned by mid 2010).
• Phase A study conducted assuming adoption of TES (design
stressing case approach).
• Additional internal cooler required by TES, KID and SiBolometer (Sorption Cooler + ADR  ~ 100 mK).
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Key role within SPICA payload complement (FIR coverage).
Herschel class instrument (c.f. SPIRE, PACS).
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SPICA ground segment
Mission Operations Centre:
• Located in Japan linked to JAXA’s SOC.
• Primary station Usuda (64m), additional
ESOC station (Cebreros / DS3).
• JAXA SOC interfaced to ESA’s SOC.
European SPICA Science Centre:
• ESA SPICA Science Centre (ESSC) located at ESAC.
• SAFARI Instrument Control Centre, distributed in several European
countries, contact via PI (SRON).
• ESSC to act as interface for the European community to the SPICA
observatory and interface between SAFARI ICC and JAXA’s SOC/MOC,
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ESA review: risk items
STA:
• Further consolidation of interface requirements.
• Focusing mechanism development (dedicated TDA planned).
• Schedule driven by M1 polishing (dedicated TDA planned).
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ESA review: risk items
STA:
• Further consolidation of interface requirements.
• Focusing mechanism development (dedicated TDA planned).
• Schedule driven by M1 polishing (dedicated TDA planned).
SAFARI:
• Further consolidation of interface requirements.
• Early selection of focal plane detector technology required.
• FTS scanning mechanism, internal cooler and FEE development (TDAs).
• Revision of development plan, in view of meeting PFM delivery date.
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Conclusions of assessment activities
The European industry and scientific community are very well
placed to contribute effectively to the SPICA mission:
• Large heritage from Herschel programme allows to exploit
expertise and to minimise the development risk.
• The Telescope Assembly is feasible and can be developed
by the European industry with an acceptable level of risk.
• The SAFARI instrument can rely on significant heritage and
expertise with the consortium (e.g. SPIRE, PACS).
• The provision of MOC and SOC services by ESA does not
present any critical issues.
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Conclusions of assessment activities
The European industry and scientific community are very well
placed to contribute effectively to the SPICA mission:
• Large heritage from Herschel programme allows to exploit
expertise and to minimise the development risk.
• The Telescope Assembly is feasible and can be developed
by the European industry with an acceptable level of risk.
• The SAFARI instrument can rely on significant heritage and
expertise with the consortium (e.g. SPIRE, PACS).
• The provision of MOC and SOC services by ESA does not
present any critical issues.
The European contribution to SPICA is a real ‘mission of opportunity’,
with the potential of a large scientific return
at a fraction of an M class mission cost.
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END
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Main telescope requirements
Main SPICA Telescope Assembly (STA) requirements applicable to the study:
Optical design:
Ritchey-Chretien, axi-symmetric, EFL=20m, M1 dia = 3.5 m
Operating temperature:
Nominal < 6K, operating range 4-10 K
Wavelength range:
5 to 210 um (goal 3.5 to 210 um)
Collecting aperture:
3.5 m diameter (maximum allowed by HII-B fairing)
Total obscuration:
< 12.5 % on axis (goal < 10%)
Total transmission:
> 90% at 5 um, > 95% at 15 um, > 99% at 110 um
Image quality:
Diffraction limited at 5 um over a FOV of 5 arcmin (WFE < 350 nm RMS, over 5’ radius)
Field Of View:
> 12 arcmin (unvignetted)
Launch environment:
JAXA launcher HII-B, cool down after launch (passive + active cooling).
STA mass allocation:
< 700 kg (including margins, excluding mass of IOB)
Stray-light rejection:
Total background from out-of-field stray sources (artificial and natural) < 20% of in-field
background (zodiacal light and self emission from telescope).
Lifetime:
> 5yr in orbit (and > 5 yr on ground)
Functional requirements:
-M2 refocusing at nominal operating temperature.
-In-flight decontamination capability.
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