LISA Pathfinder platform stability and drag-free performance
OA Location
Author(s)
Type
Journal Article
Abstract
The science operations of the LISA Pathfinder mission have demonstrated the feasibility of sub-femto-g free fall of macroscopic test masses necessary to build a gravitational wave observatory in space such as LISA. While the main focus of interest, i.e., the optical axis or the x-axis, has been extensively studied, it is also of great importance to evaluate the stability of the spacecraft with respect to all the other degrees of freedom (d.o.f.). The current paper is dedicated to such a study: the exhaustive and quantitative evaluation of the imperfections and dynamical effects that impact the stability with respect to its local geodesic. A model of the complete closed-loop system provides a comprehensive understanding of each component of the in-loop coordinates spectral density. As will be presented, this model gives very good agreement with LISA Pathfinder flight data. It allows one to identify the noise source at the origin and the physical phenomena underlying the couplings. From this, the stability performance of the spacecraft with respect to its geodesic is extracted as a function of frequency. Close to 1 mHz, the stability of the spacecraft on the XSC, YSC and ZSC d.o.f. is shown to be of the order of 5.0×10−15 m s−2 Hz−1/2 for X, 6.0×10−14 m s−2 Hz−1/2 for Y, and 4.0×10−14 m s−2 Hz−1/2 for Z. For the angular d.o.f., the values are of the order of 3×10−12 rad s−2 Hz−1/2 for ΘSC, 5×10−13 rad s−2 Hz−1/2 for HSC, and 3×10−13 rad s−2 Hz−1/2 for ΦSC. Below 1 mHz, however, the stability performances are worsened significantly by the effect of the star tracker noise on the closed-loop system. It is worth noting that LISA is expected to be spared from such concerns, as differential wave-front sensing, an attitude sensor system of much higher precision, will be utilized for attitude control.
Date Issued
2019-04-15
Date Acceptance
2019-03-08
Citation
Physical Review D - Particles, Fields, Gravitation and Cosmology, 2019, 99 (8)
ISSN
1550-2368
Publisher
American Physical Society
Journal / Book Title
Physical Review D - Particles, Fields, Gravitation and Cosmology
Volume
99
Issue
8
Copyright Statement
© 2019 American Physical Society
Sponsor
Science and Technology Facilities Council (STFC)
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000464746300001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Grant Number
ST/R001871/1
Subjects
Science & Technology
Physical Sciences
Astronomy & Astrophysics
Physics, Particles & Fields
Physics
Publication Status
Published
Article Number
ARTN 082001
Date Publish Online
2019-04-16