{"id":96252,"date":"2018-03-11T10:16:26","date_gmt":"2018-03-11T10:16:26","guid":{"rendered":"https:\/\/www.deberes.net\/tesis\/sin-categoria\/development-and-validation-of-the-thermal-diagnostics-instrumentation-in-lisa-pathfinder\/"},"modified":"2018-03-11T10:16:26","modified_gmt":"2018-03-11T10:16:26","slug":"development-and-validation-of-the-thermal-diagnostics-instrumentation-in-lisa-pathfinder","status":"publish","type":"post","link":"https:\/\/www.deberes.net\/tesis\/tecnologia-de-la-instrumentacion\/development-and-validation-of-the-thermal-diagnostics-instrumentation-in-lisa-pathfinder\/","title":{"rendered":"Development and validation of the thermal diagnostics instrumentation in lisa pathfinder"},"content":{"rendered":"<h2>Tesis doctoral de <strong> Jose SanJuan <\/strong><\/h2>\n<p>This thesis focuses on the issues related to the thermal diagnostics aboard the space mission lisa pathfinder (lpf).  lpf is a technological mission devoted to put to test critical subsystems for the lisa mission. Lisa will be the first space born  gravitational wave (gw) observatory with the main objective of detecting gws. Gws are ripples of the space-time geometry caused  by acceleration of masses in an asymmetric way. Their detection requires put test masses (tms) in an almost perfect inertial frame  (or free fall).    non-inertial forces perturbing the tms must be less than 6 fn\/sqrt(hz) in the frequency range of 0.1 mhz to 0.1 hz and the noise in  the measurement between the tms (separated by 5 gm) must be of 40 pm\/sqrt(hz) in the same band. To reduce the risks of a direct  launch of lisa, esa has decided to first launch lpf to put all the lisa technologies to test.  the payload of lpf, the lisa technology package (ltp), contains two tms placed in two cylinders inside a single spacecraft (sc)  and an interferometric system that measures the relative distance between them. The sc isolates the tms from the external  disturbances but internal stray forces will still perturb the tms. Their levels must be bounded not to challenge the free fall accuracy.  one of these disturbances is temperature fluctuations and the aspects related to their measurement are the leitmotif of this thesis.     in chapter 1 we have presented how temperature fluctuations couple into the key subsystems of the ltp to degrade their  performance. The foreseen effects are radiation pressure, radiometer effect, temperature coefficient of optical components, etc. On- ground estimations conclude that the temperature stability in the ltp must be less than 100 microk\/sqrt(hz) in the frequency range  of 1 mhz to 30 mhz (ltp band). Since temperature fluctuations are an important issue in lpf and in lisa, a thermal diagnostic  subsystem is needed aboard both missions.    the task of the thermal diagnostics in the ltp is twofold: on the one hand, temperature fluctuations in different subsystems must be  measured with noise levels of 10 microk\/sqrt(hz) in the ltp band. On the other hand, a set of heaters will generate heat pulses that  in conjunction with temperature measurements will be used to estimate the actual coupling between temperature and systems  performance. These actions will provide information on the behaviour of the system and will permit to identify the fraction of noise in  the system coming from temperature issues. The main function of lpf, as precursor mission of lisa, is the understanding of all the  noise sources in the system. This will provide clues to the final leap from lpf sensitivity to lisa one.     the main investigations carried out during this thesis can be split into three main categories: (i) the design and validation of the ltp  temperature measurement subsystem (tms); (ii) the extension of the system to the lisa requirements; and (iii) the analysis of the  in-flight thermal experiments in the ltp. The thesis is organised as follows: in chapter 2 we describe the designed electronics and  the temperature sensors chosen. Aspects related to the coupling of the tms with other subsystems nearby are discussed in chapter  3. Chapter 4 focuses on the design of the testbed needed for the validation of the tms. Two different testbeds are described: one for  the ltp measurement bandwidth (mbw) and another one for the lisa mbw, 0.1 mhz. In chapter 5 we present the results of the  test campaigns: the prototype, the engineering model and the flight model systems were put to test. The results of the investigations  in the lisa band are also shown. Chapter 6 contains investigations in view of lisa requirements to reduce excess noise at very low  frequency and to reduce the floor noise of the measurement. Chapter 7 focuses on the thermal experiment on-board lpf: a set of  thermal excitations are proposed to extract information of the thermal behaviour of the key subsystems of the ltp.<\/p>\n<p>&nbsp;<\/p>\n<h3>Datos acad\u00e9micos de la tesis doctoral \u00ab<strong>Development and validation of the thermal diagnostics instrumentation in lisa pathfinder<\/strong>\u00ab<\/h3>\n<ul>\n<li><strong>T\u00edtulo de la tesis:<\/strong>\u00a0 Development and validation of the thermal diagnostics instrumentation in lisa pathfinder <\/li>\n<li><strong>Autor:<\/strong>\u00a0 Jose SanJuan <\/li>\n<li><strong>Universidad:<\/strong>\u00a0 Polit\u00e9cnica de catalunya<\/li>\n<li><strong>Fecha de lectura de la tesis:<\/strong>\u00a0 28\/09\/2009<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<h3>Direcci\u00f3n y tribunal<\/h3>\n<ul>\n<li><strong>Director de la tesis<\/strong>\n<ul>\n<li>Juan Ramos Castro<\/li>\n<\/ul>\n<\/li>\n<li><strong>Tribunal<\/strong>\n<ul>\n<li>Presidente del tribunal: stefano Vitale <\/li>\n<li>serni Ribo vedrilla (vocal)<\/li>\n<li>Miguel Garc\u00eda hern\u00e1ndez (vocal)<\/li>\n<li>  (vocal)<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Tesis doctoral de Jose SanJuan This thesis focuses on the issues related to the thermal diagnostics aboard the space mission 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