20160212 riameeting lisapathfinder · • ligo just initiated gravitational wave astronomy! •...

LISA PathfinderSpanish contribution to space-borne gravitational wave detection

Miquel NofrariasInstitut de Ciències de l’Espai (IEEC-CSIC)

M. NofrariasRIA-Spacetec, Madrid 12/02/16

LISA Pathfinder: tracking spacetime

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• LISA Pathfinder aims to test key technologies for gravitational wave detection in space

• The main objective is to achieve a nominal geodesic motion in space: Sa = 3 x 10-14 m/s2/√Hz at f = 1mHz


LISA Pathfinder: tracking spacetime

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Spanish contribution

• The Spanish contribution is the Data and Diagnostics Subsystem (DDS)

- Data Management Unit - Temperature sensors, Magnetometers, Radiation Monitor - Heater, Magnetic Coils

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Spanish contribution

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• Spanish contribution is the Data and Diagnostics Subsystem, led by the Institut de Ciències de l’Espai (IEEC-CSIC). In collaboration with NTE-SENER, UPC, IFAE

Data Management Unit

Commanding and control of LTP subsystems. Single command interface to S/C Provides power supply and Processing to Diagnostics Implements Optical Metrology control loops

Radiation Monitor Thermal diagnostic subsystem Magnetic diagnostic subsystem

2 PIN diodes in telescope conf.Measuring energy deposition for coincidence events

24 sensors (10-5 K/√Hz)16 heatersMonitor and charac. of thermal sensitive locations

4 fluxgate magnetometers (10 nT/√Hz)

2 coils (100 nA/√Hz)Monitor and charac. of test mass magnetic properties


Spanish contribution: diagnostics science lead

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Leading Diagnostics Working Group: Experiment definition and data analysis pipeline development



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• Functionality: - Provides single command and control

interface to S/C (except TM att. contrl.)

- Generation and distribution of LTP master clock and sync. signals.

- Commanding and control of LTP subsystems: IS FEE SAU, IS CCU, UVLU, OMS PM, OMS LA.

- Monitors essential LTP HK data

- Provides power supply to DI, processing DI data



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• Hardware: - 24MHz CPU, working at 12MHz - 64k x 8bit PROM (boot loader) - 256k x 32bit EEPROM (pers. data) - 512k x 40bit RAM runtime - 2 MIL-STD-1553 bus interface - 3 serial port

• Software: - ECSS-E40-Part 1B standard codification - 406646 LOC (C99, Python, Assembler) - 4.7 lines of test per LOC - Real-time embedded RTems for ASW

• Software Verification Facility (SVF): - DMU simulator, LTP subsystem emulator

- Functional tests


Radiation monitor

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• LPF radiation monitor - 2 silicon PIN diodes - Telescope configuration

(red. 10% angular acceptance) - Copper shield stopping protons

E < 70 MeV - FEE determines:

• single-events • energy deposition for

coincidence events

• Achieved performance: - Max. count rate > 6300 p/s (req. 5000 p/s) - Energy spectrum [0-5]Mev , ∆E = 5KeV


Magnetic diagnostic subsystem

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• Aim: study magnetic coupling of free-falling test masses to the environment • mapping the magnetic field on-board

SB ≤ 10-8 T/Hz1/2 , 10-3 < f < 10-1 Hz

• induce controlled perturbations SI ≤ 10-7 A/Hz1/2 , 10-3 < f < 10-1 Hz

• Experiment: induce magnetic modulations of ~5uT on test mass. Resulting force on the test mass ~ pN


Thermal diagnostics subsystem

• 24 high precision sensors located in the most temperature-sensitive locations

• 14 heaters to apply controlled perturbations in these locations

• Achieved unprecedented sensitivity: ST= 10-5 K/√Hz at f = 1mHz

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Noise characterisation experiments: thermal

• Aim: study thermal coupling of free-falling test masses to the environment

• Experiment: induce control modulations of ~40mK across the housing. Resulting force on the test mass ~2pN

- provides pressures estimate on-board

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Noise characterisation experiments: thermo-elastic

• Thermo-elastic studies planned during in-flight operations, but already took place on ground (Nov. 11)

- F. Gibert et al. Thermo-elastic induced phase noise in the LISA Pathfinder spacecraft CQG 045014 (2015)

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• Derived this contribution to be 1 pm√Hz at 1mHz


Chronology

2015 Dec. 3: Lift off from French Guiana (Vega VV06 flight)

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2015 Dec. 3-13: LEOP, apogee raising manoeuvres

2016 Jan. 2: Colloidal thruster commissioning

2016 Jan. 11: DMU switch on, diagnostics

check-out

2016 Jan. 13: Laser switches on

2016 Jan. 22: Propulsion module separation

2016 Feb. 3: Handover to Grabbing, Position

and Release mechanism

2016 Jan. 15-16: Test mass release

Steps forward


Steps forwards #1: magnetic sensing

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• Implemented in 3Cat-2 CubeSat as technology demonstrator (launch 2016)

- AMR-based magnetic diagnostic on-board - Raising TRL level - Reaching stringent size and power reqs. - Testing low-frequency noise behaviour in space

• New magnetic sensing: from fluxgate to Anisotropic Magneto-resistors (AMR)

- Less bulky, reducing back-action


Steps forwards #2: Ultra-stable optical metrology

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• Aim: develop an infrastructure to test GW technologies at low frequencies

• Funded by Marie Curie CIG Grant (2011-15)

• Main objectives:

- Implement a low-frequency stabilised thermal environment (10-4 Hz)

- Implement a basic interferometer, based in deep phase modulation scheme

- Combine both to test key technologies at very low frequencies: materials, optoelectronics, etc.

Frequency [Hz]

Am

plitu

de s

pect

rum

den

sity

[m/H

z1/2 ]

10−5 10−4 10−3 10−210−12

10−11

10−10

10−9

10−8

10−7

10−6

10−5

10−4

Ifo.1st Pred.1st Subt.2nd Pred.2nd Subt.

M Nofrarias et al. Phys. Rev. D 87, 102003 (2013)



• Developing acquired know-how with LISA Pathfinder

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Metrology: deep-phase modulation Mach-Zehnder laser interferometer.

Thermal: stabilised vacuum chamber. Design of a passive thermal insulation to suppress low-frequency

Software: phasemeter implemented as embedded LEON3 soft-core CPU in FPGA



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Jan. 2013

May 2014 Oct. 2014

May 2015 Dec. 2015


Steps forwards #3: High precision temperature sensors

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• ComFuturo: private funded grants to young scientist to develop their projects (3yr) in a CSIC institution. Managed by Fundación General CSIC

• First edition 2015, 14 awards in Spain: • High precision sensors for temperature control in

space missions (M. Nofrarias)

• Aim: design a temperature sensor based in opto-mechanical resonators reaching ~nK/√Hz. Miniaturise technology to test in flight conditions (TRL6)

• Compact, non-magnetic, high precision


Conclusions

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• LIGO just initiated Gravitational Wave Astronomy! • LISA Pathfinder is already flying, commissioning ongoing

- Test mass release planned for 15-16th Feb- Science operations planned for 1st March

• Spanish contributions is the Data and Diagnostics subsystem with important impact in science

• We keep pushing ultra-stable technologies (~𝜇Hz) forward to support a future space-borne GW observatory

- Thermal- Magnetics- Metrology

20160212 riameeting lisapathfinder · • ligo just initiated gravitational wave astronomy! •...

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