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Space-based gravitational wave observatories: Learning from the past, moving towards the future
Neil J. Cornish
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Outline
•We are in the Gravitational Wave decade!
• Status of Space GW detection in Europe & US
• LISA Technology developments in US
• LISA Science development in US
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The 10’s: Decade of Gravitational Waves
• BICEP2 detection in 2014
• LIGO/Virgo detection in ~ 2016
• IPTA detection in ~ 2018
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LIGO sensitivity over time
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LIGO/Virgo Prediction
[LIGO & Virgo Collaborations, arXiv:1304.0670 (2013)]
Cum
ulativ
e #
NS-
NS
dete
ctio
ns
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Pulsar Timing in hot pursuit
100 ns
Likely detection with ~40 pulsars at ~100 ns timing accuracy
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Pulsar Timing: NANOGrav Prediction
[X. Siemens, J. Ellis, F. Jenet, J. Romano, Class. Quant. Grav. 30, 224015 (2013)]
2005
2010
2015
2020
2025
Year
0.0
0.2
0.4
0.6
0.8
1.0
Det
ection
Pro
bab
ility
2018 2024
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Space GW Status in Europe and U.S.
The “Gravitational Universe” selected as the third large Cosmic Vision (L3) science theme. Mission concept: eLISA (evolved Laser Interferometer Space Antenna).
Launch: 2035+ (~10 years too late)
LISA Pathfinder on schedule
Launch: July 31, 2015 (~10 years too early)
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Schedule unchanged for over a year
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Key LISA technologies
Elements in red tested by pathfinder
Free flying test mass subject to very low parasitic forces:– Drag free control of spacecraft (non-contacting spacecraft)– Low noise microthruster to implement drag-free– Large gaps, heavy masses with caging mechanism– High stability electrical actuation on cross degrees of freedom– Non contacting discharging of test-masses– High thermo-mechanical stability of S/C– Gravitational field cancellation
Precision interferometric, local ranging of test-mass and spacecraft:– pm resolution ranging, sub-mrad alignments– High stability monolithic optical assemblies
Precision 1 million km spacecraft to spacecraft precision ranging:– High stability telescopes– High accuracy phase-meter– High accuracy frequency stabilization– Constellation acquisition– Precision attitude control of S/C
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Pathfinder & ST7
GAIA cold gas thrusters
NASA colloidal thrusters (ST7)
Great opportunity for US scientists to participate in full LPF analysis almost for free ( ~1/1000 ESA cost )
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Key LISA technologies
Elements in red tested by pathfinder
Free flying test mass subject to very low parasitic forces:– Drag free control of spacecraft (non-contacting spacecraft)– Low noise microthruster to implement drag-free– Large gaps, heavy masses with caging mechanism– High stability electrical actuation on cross degrees of freedom– Non contacting discharging of test-masses– High thermo-mechanical stability of S/C– Gravitational field cancellation
Precision interferometric, local ranging of test-mass and spacecraft:– pm resolution ranging, sub-mrad alignments– High stability monolithic optical assemblies
Precision 1 million km spacecraft to spacecraft precision ranging:– High stability telescopes– High accuracy phase-meter– High accuracy frequency stabilization– Constellation acquisition– Precision attitude control of S/C
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LISA technology developments in US
– High accuracy phase-meter– High accuracy frequency stabilization– Constellation acquisition
JPL - GRACE Follow on
UF - – High stability telescope metrology– Torsion pendulum for DRS studies
Session Y15: Gravitational Wave Experiment1:30 PM–3:06 PM, Tuesday, April 8, 2014Room: 103Y15.00008 The UF torsion pendulum and its role in space-based gravitational wave detectors Y15.00007 Sensing and actuation system for the University of Florida Torsion Pendulum for LISA
Goddard - – High stability telescope– High accuracy frequency stabilization
Stanford - – UV LED Charge control (on an CUBESAT)
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LISA Science developments in US
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Parting thoughts
• Is a junior partnership in L3 the best path forward for NASA?
• Should we consider taking the lead in this new branch of astronomy?
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