(ed.). Gravitational waves (IOP, 2001)(422s).

Description of the LISA mission 127Figure 10.6. Early ONERA design of LISA free mass sensor called CAESAR. Up to fourcapacitor plates on each face of the housing around the test mass allow the relative positionand angular orientation to be measured accurately. Electrical forces also can be applied, ifdesired.After completion of the initial CAESAR design, additional studies of freemass sensor designs and of the LISA requirements have been carried out,influenced strongly by the CAESAR design. A number of the factors influencingthe design were discussed by Speake [19] and by Vitale and Speake [20]. A designwith a considerably different geometry for the capacitor plates was investigated byJosselin, Rodrigues and Touboul [21], and has since been constructed and testedin the laboratory and the LISA free mass sensor requirements were simplified andsomewhat relaxed [6].One current version of the error allocation budget for the free mass sensoris described in section 4.2.3 of [6]. The total acceleration error allowed forone sensor is 3 × 10 −15 ms −2 /rtHz over the frequency range 0.1–30 mHz.The six largest allocations to individual error sources are as follows: thermaldistortion of the main spacecraft; temperature difference variations across the