Conception and Design of New Space Instrumentation for the Study of Massive Stars in the UV

In astrophysics, the UV domain is rich in important information that can be exploited by a multitude of groups of scientists, working on a variety of subjects. Because of the Earth atmosphere, it is not possible to observe this spectral domain from the ground and therefore space observatories are needed to provide the scientific data. Motivated by the study of the properties of massive stars in the UV, this thesis is dedicated to the design of new space instrumentation dedicated to this scientific purpose.
In the first part, the conception of an in-flight calibration unit is investigated to answer the needs of a large instrument proposed to ESA calls for medium-sized missions. The instrument is a large telescope working with a VISIBLE-UV spectro-polarimeter which covers a very wide range of wavelength from 119 nm to 888 nm. First, the basic principles of optical calibration are presented as well as some heritage in calibration unit design at CSL. Some calibration elements, such as lamps, are also presented. Eventually, the existing concepts and calibration elements are used and integrated in an innovative design of calibration unit that fulfill the needs of the large instrument.
The second part is dedicated to UV instrumentation on-board very small satellites that are based on the Cubesat standard. After presenting the standard and the previous Cubesat missions, feasibility studies of two instruments are conducted. The first instrument is a near UV telescope designed to be integrated in a 3U Cubesat and to observe bright massive stars. There is no previous Cubesat missions designed to do astronomical UV observations. The challenge was then to design an instrument optimized for UV while being compliant with the Cubesat standard. The optical design, the entire satellite and a mission analysis are discussed in the manuscript. Based on all the previous points, a photometric budget is carried out to demonstrate the efficiency of the system. The second instrument is a near-UV low-resolution spectro-polarimeter which is presented as a potential technology demonstrator in relation with the above-described medium-sized mission.