UCL Astrophysics Group


PhD Projects: Astronomical Instrumentation

Ground calibration of the Litebird Cosmic Microwave Background satellite mission

Litebird is a JAXA (Japan Space Agency) satellite which is being built in collaboration with a wide group of countries including the UK, US, and a European consortium and will be launched in the early 2030s. Working in the far-infrared and mm-wave it comprises of 3 separate telescopes working at different wavelengths adopting a range of complementary technology to measure with enormous accuracy the pattern of polarised emission imprinted in the cosmic microwave background in order to detect evidence of inflation. To achieve this, Litebird makes use of large focal plane arrays of detectors coupled to refractive telescopes (for the shorter wavelengths and a reflective one for the longer wavelength telescope) as well as fast-modulating Half-Wave plates. For this mission to succeed the level of calibration of all the sub-systems needs to achieve a degree of precision which is unprecedented.

This project aims to participate in the design and planning of the calibration activities within the mission consortium creating an accurate model of how these tests will provide the necessary data that will allow cosmologists to reach the required sensitivity the mission is designed for.

Experience in any of optics, spectroscopy, polarimetry and detector physics will be beneficial.

Contact: Prof Giorgio Savini (g.savini AT ucl.ac.uk)

Design of a UV spectroscopy payload for Cubesat Astronomy

UV astronomy has always relied on being able to perform astrophysical investigations above the atmosphere. As a field, UV spectroscopy has not been able to thrive similarly to optical astronomy because of this, and is constantly competing with a range of other science fields in funding experiments on space satellites to study this wavelength range. Unlike other fields (IR and mm-wave) though, UV astronomy deals with energetic photons and is less affected by issues of payload thermal emission. Furthermore, the specific field of UV spectroscopy of stars can relax many other stringent requirements (imaging resolution and field of view) allowing small satellites with limited power provision to perform investigations which are of interest and relevant to current investigation of active stars. Exoplanet studies are at present focusing on the atmospheric properties of the planets discovered, but the vast majority of which are far close to their host star than the planets we are used to on the Solar System. Due to their proximity to their star, stellar activity and the star-planet interaction (including that of the magnetic fields) is key to understanding the nature and evolution of such exoplanets.

A small satellite (including cubesats) can provide a useful and economic platform for a small payload that delivers UV spectroscopy. This projects aim to design a small and contained payload that can be hosted on either a multi-unit cube-sat or on other small satellites as a hosted payload. 

A student on this project would participate in the design, breadboard build and test campaign of such a unit. 

Experience in optics, spectroscopy and electronics is beneficial.

Contact: Prof Giorgio Savini (g.savini AT ucl.ac.uk)

In-flight commissioning and calibration of the Ariel satellite mission

Ariel is a European Space Agency M-class mission to be launched in 2029. Its objective is to measure the spectra of ~1000 exoplanet atmospheres in order to better understand the chemical composition of both planets and their atmospheres and provide a better understanding of planetary origin in different stellar systems. The payload of Ariel consists of two instrument blocks. The first instrument consists of 3 photometric channels to monitor stellar variability and provide accurate pointing information to the satellite as well as a Near-infrared spectrometer. The second instrument consists of two IR spectrometers reaching a wavelength of 8 microns which will detect a range of molecular signatures of interest. The instruments will undergo thorough testing throughout the build phase in the respective institutes
contributing to the payload prior to launch, but will subsequently require a detailed testing procedure once launched during the commissioning phase.

This project aims to model the instrument in detail and design a comprehensive set of tests which the instruments will have to perform after launch and before entering the nominal science operation period.

Experience in optics, spectroscopy and detector physics is beneficial.

Contact: Prof Giorgio Savini (g.savini AT ucl.ac.uk)