München 2009 – scientific programme

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GR: Fachverband Gravitation und Relativitätstheorie

GR 13: Gravitationswellen II

GR 13.2: Talk

Thursday, March 12, 2009, 17:05–17:25, A214

LISA onboard ranging and data communication capabilities — •Juan Jose Esteban Delgado, Antonio Garcia Marin, Iouri Bykov, Johannes Eichholz, Joachim Kullmann, Gerhard Heinzel, and Karsten Danzmann — Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut) and Universität Hannover. Callinstrasse 38 30167 Hannover, Deutschland

The Laser Interferometer Space Antenna (LISA) is a joint ESA and NASA mission to detect and observe gravitational waves from low-frequency sources. LISA consists of three spacecraft separated by 5 million kilometers forming an equilateral triangle and communicated via three bidirectional laser links. The primary quantity to be measured is the relative pathlength variation between the free-floating test masses onboard two different spacecraft by means of heterodyne interferometry with picometer sensitivity.

Due to relative movements between the spacecraft, the interferometer arms are unequal and time-varying. Therefore, to achieve the necessary interferometric sensitivity, the absolute distance between the spacecraft has to be measured. To this end, the LISA lasers must be phase modulated with pseudo-random noise sidebands, which also enable data transfer between the satellites.

This work presents a modulation scheme with submeter ranging accuracy and several kilobytes data rate. Its functionality was already demonstrated in a software simulation and in a FPGA-based hardware implementation. The next step will be an optical experiment with LISA representative hardware.