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.
| Identifer | oai:union.ndltd.org:unitn.it/oai:iris.unitn.it:11572/367984 |
| Date | January 2015 |
| Creators | Russano, Giuliana |
| Contributors | Russano, Giuliana |
| Publisher | Università degli studi di Trento, place:TRENTO |
| Source Sets | Università di Trento |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | firstpage:1, lastpage:132, numberofpages:132 |
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