The LISA Pathfinder geodesic explorer mission for gravitational wave astronomy aims to measure a residual differential acceleration noise approaching the femto-m/s^2/Hz^1/2 levels needed for eLISA. This measurement is complicated by a large, roughly nm/s^2, stable differential gravitational acceleration that must be actively compensated in order to hold the test particles centred inside an orbiting apparatus. The actuation force applied to compensate this effect introduces a dominant source of force noise in the mission noise budget. To suppress this noise source and avoid actuation instabilities, a “free-fall†actuation control scheme has been designed: actuation is limited to brief impulses, with test masses in free fall in between two “kicks†, with this actuation-free motion then analysed for the remaining sources of acceleration ultra noise. In this work, we present the results from an extensive on-ground torsion pendulum test of this free-fall technique, which to date allows an equivalent acceleration noise measurement at the 100 fm/s^2/sqrt(Hz), a factor 3 above the LISA Pathfinder spec. We will discuss both experimental and analysis limitations to the ground experiment and some implications for the flight test.

A torsion pendulum ground test of the LISA Pathfinder Free-fall mode / Russano, Giuliana. - (2015), pp. 1-132.

A torsion pendulum ground test of the LISA Pathfinder Free-fall mode

Russano, Giuliana
2015-01-01

Abstract

The LISA Pathfinder geodesic explorer mission for gravitational wave astronomy aims to measure a residual differential acceleration noise approaching the femto-m/s^2/Hz^1/2 levels needed for eLISA. This measurement is complicated by a large, roughly nm/s^2, stable differential gravitational acceleration that must be actively compensated in order to hold the test particles centred inside an orbiting apparatus. The actuation force applied to compensate this effect introduces a dominant source of force noise in the mission noise budget. To suppress this noise source and avoid actuation instabilities, a “free-fall†actuation control scheme has been designed: actuation is limited to brief impulses, with test masses in free fall in between two “kicks†, with this actuation-free motion then analysed for the remaining sources of acceleration ultra noise. In this work, we present the results from an extensive on-ground torsion pendulum test of this free-fall technique, which to date allows an equivalent acceleration noise measurement at the 100 fm/s^2/sqrt(Hz), a factor 3 above the LISA Pathfinder spec. We will discuss both experimental and analysis limitations to the ground experiment and some implications for the flight test.
2015
27
Physics
Weber, William
Inglese
Settore FIS/05 - Astronomia e Astrofisica
Settore FIS/01 - Fisica Sperimentale
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11572/367984
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