Pre-Phase A Report - Lisa - Nasa

viii Contents
2.8TheLISAconcept............................... 47
2.8.1Overview ............................... 47
2.8.2Lasers ................................. 50
2.8.3Drag-freeandattitudecontrol.................... 50
2.8.4Ultrastablestructures......................... 51
3 Experiment Description 53
3.1Theinterferometer .............................. 53
3.1.1Introduction.............................. 53
3.1.2Phaselockingandheterodynedetection .............. 54
3.1.3Interferometriclayout ........................ 54
3.1.4Systemrequirements ......................... 57
3.1.5Lasersystem ............................. 58
3.1.6Laserperformance .......................... 61
3.1.7 Thermal stability ........................... 63
3.1.8 Pointing stability ........................... 64
3.1.9Pointingacquisition.......................... 65
3.1.10Finalfocusingandpointingcalibration............... 65
3.1.11Pointahead.............................. 65
3.2Theinertialsensor .............................. 66
3.2.1Overview ............................... 66
3.2.2 CAESAR sensorhead......................... 67
3.2.3Electronicsconfiguration....................... 68
3.2.4Evaluationofperformances ..................... 71
3.2.5Sensoroperationmodes ....................... 72
3.2.6Proof-masschargecontrol ...................... 73
3.3Drag-free/attitudecontrolsystem ...................... 74
3.3.1Description .............................. 74
3.3.2 DFACS controllermodes ....................... 75
3.3.3Autonomousstartrackers ...................... 76
4 Measurement Sensitivity 79
4.1Sensitivity................................... 79
4.1.1Theinterferometerresponse...................... 79
4.1.2Thenoiseeffects. ........................... 80
4.1.3Thenoisetypes............................. 81
4.2Noisesanderrorsources ........................... 82
4.2.1Shotnoise............................... 82
4.2.2 Optical-path noise budget . . .................... 83
3-3-1999 9:33 Corrected version 2.08