SPICA / AIV&T issuesSpacecraft test program & model philosophy (tentative plan)

Feb. 19 2010 revised

Nov. 19, 2009 1st draft

by

H. Matsuhara, N. Takahashi, T. Nakagawa

ＳＰＩＣＡ Telescope Assembly (STA)

3m-class cooled telescope Monolithic Mirror

Ceramic material (SiC)

No deployable mechanism Simple, Feasible, Reliable

Smooth PSF Essential for Coronagraph

Herschel & AKARI Heritage SPICA: WFE 0.35μm, 5K (3.5m) AKARI: WFE 0.35μm, 6K (70cm) Herschel: WFE 6μm, 80K (3.5m)

STA models & proposed delivery (tentative plan)

STM (Structure Thermal Model) Proposed delivery : Oct. 2012 (beginning of 3Q

of FY2012) AIT plan

Integrated as PLM (STM) Thermal test at cold (@Tsukuba 13m chamber) Integrated into Spacecraft (STM) Spacecraft Mechanical Environmental test & Thermal

Vacuum TestFM

Proposed delivery : Jan. 2017 (beginning of 4Q 2016)

STA Optical Performance test at cold (1)

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Date & duration ： 1Q of CY2017, 1-2 months

Place : 6m Space Chamber in Tsukuba Space

Center Configuration

IOB （ＦＭ）＋ STA(FM) Additional thermal sheild in the chamber

Purposes: Optical performance evaluation of ＳＴＡ at <10K Multiple measurements are connected by the

Stitching Method

STA Optical Performance test at cold (2)

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Anti-Vibration Table

Test Specimen Mount Table (with Shroud)

Pillar of V

acuum V

essel

Independent Foundation

Cryo Sorption Pumps

AC

F

Turbo Molecular Pumps

Gear

Motor

Interferometer

GHe

LN2

LN2 Shroud

GHe Shroud

AC

F

1

2

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5

67

8

STA Flat-mirror

5-axis stage

PLM Thermal Test at cold

Purpose Evaluation of PLM cooling

system performances Date & Duration

STM: April 2013 FM: Dec. 2017, ~2months

Method Additional shields in the

existing 13m space chamber in Tsukuba

Shields are externally lifted by mechanical coolers

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SPICA AIV&T timeline (tentative)

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Key issues for FPI AIV&T

FPI’s system-level test plan should take account of the critical issues as below: (a) FPI is cooled to <5K with J-T coolers under

extremely careful Spacecraft thermal design. (b) disturbance and interference from J-T

coolers and AOCS (such as RW, gyro) To assure high-sensitivity (low-noise) in orbit

(c) Co-operation with FPC-G to establish the pointing stability

Interferences? Alignment? (d) Co-focus among FPIs (especially MIR’s)

Since STA 2ry cannot be adjusted so frequently in orbit

FPI Model philosophy Cold FPIs

Minimum number of Models required for the system level test (in the previous page) is:

FM (Flight Model) (& its spare) STM : structure thermal model CQM : cold qualification model

Delivery date of FM: June 2016 (August 2016 at worst) in the proposed scenario.

Warm Electronics Similar as above, except for the terminology (CQM PM

(proto-model) Spacecraft DHS simulator(SpaceWire I/F) will be developed,

and distributed hopefully before 2014 ( under discussion)

STM (Structure Thermal Model) for FPIs

Description Mechanical I/F specifications (including disturbance

sources) is equivalent to that of FM Required Function

Same mechanical I/F specifications to FM Nearly the same thermal I/F (TBD, for spacecraft(PM)

thermal test) Equipped with thermometers, acceleration sensors for

measurement of I/F environmental condition Simulate mechanical disturbance according to the system

operation modes Proposed Delivery

Oct. 2012 : before starting of assembly of PLM(STM) for the system Mechanical & Thermal Test

CQM (Cold Qualification Model) for FPIs

Description Nearly equivalent to FM incorporating with detectors

operable at low-temperature expected in orbit Required Function

Same thermal, mechanical, electrical I/F specifications to FM

Equipped with detectors operable at low-temperature, with the same noise performance as that of FM

Simulate heat-dissipation (load to J-Ts), mechanical disturbance according to the system operation modes

Proposed Delivery Apr. 2015 : when the PLM(FM) is available for us to

test the items (a), (b), & (c) in page 8.

FPI: ＳＰＩＣＡ system test plan

With STM: Mechanical Environmental test & thermal test at cold at the

PLM level Mechanical Environmental test & Thermal vacuum test at

Spacecraft level Measure disturbance at FPI from J-T cooler/AOCS

With CQM: Cooling compliance test with J-T (PM) Evaluate effect of mechanical disturbances from J-T (PM) and

AOCS simulator, Evaluate electrical interferences among FPIs, J-T, AOCS in

the latter half of FY2015 With FM

FPI evaluation at cold (optical & electrical) STA optical performance test at cold Thermal test at cold at PLM level

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Focal Plane Instrument Assembly (FPIA) = IOB+FPI

TOB ： Telescope Optical Bench

IOB: Instrument Optical Bench

13

2300

FPI Evaluation at cold (1)

Date & Duration: latter half of CY2016, 1-2 months

Place ： 6m Space Chamber at Tsukuba Space Centre (tbd)

Configuration: IOB(FM dummy) ＋ FPI(FM) ＋ cooler(TBD) ＋ FPI

warm electronics (FM) ( ＋ STA Simulator..) Purposes:

With all FM FPIs together, all functional, electrical & optical performance evaluation at cold (operating temperature in orbit) as well as interference test.

Optical performance will be measures with a STA simulator.

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IOB

FPI FPI

LHe

Mech. cooler

FPI Evaluation at cold (2)

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