2026-09-20T03:48:44Zhttps://iris.unitn.it/oai/requestoai:iris.unitn.it:11572/3679842026-04-03T00:46:47Zcom_11572_237821com_11572_101871col_11572_237822ou_ou00011
A torsion pendulum ground test of the LISA Pathfinder Free-fall mode
Russano, Giuliana
Russano, Giuliana
Settore FIS/05 - Astronomia e Astrofisica
Settore FIS/01 - Fisica Sperimentale
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
info:eu-repo/semantics/doctoralThesis
https://hdl.handle.net/11572/367984
http://dx.doi.org/10.15168/11572_367984
10.15168/11572_367984
eng
firstpage:1
lastpage:132
numberofpages:132
info:eu-repo/semantics/openAccess
Università degli studi di Trento
place:TRENTO
license:Tutti i diritti riservati (All rights reserved)