Open PhD opportunities

Satellite microvibration source characterization

The main aim of this project is to develop a methodology to fully characterise sources of microvibration on-board satellites. Microvibrations are low amplitude dynamic disturbances occurring at frequencies up to several hundred Hertz and produced by the functioning of on board equipment such as reaction wheel assemblies, cryo coolers etc.
These vibrations propagate through the satellite structure, and although they do not pose risks for the spacecrafts mechanical integrity, they can seriously degrade the performance of accurately targeted optical payloads, such as high resolution cameras or telescopes.

In order to predict the level of stability of the payload it is necessary to have a high quality mathematical model of the microvibration sources. Measurements of blocked reactions obtained with the equipment mounted on a dynamometric table are insufficient to correctly reproduce the effect of the microvibration source on the satellite, and measurements of the dynamic mass of the sources to include the effect of the coupling between source and satellite structure, are complicated and time consuming.

The development of an efficient semi-empirical methodology to characterise existing sources, and modelling technique to integrate them with a satellite structural model will be the core research activity. In addition to theoretical and computational work the project is expected to include some experimental activity to validate the methodology, and it will be carried out in cooperation with Industry.

For more information or to apply, please contact: g.aglietti@auckland.ac.nz

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Spacecraft launch environment and vibration testing

The main aim of this project is to investigate and improve some aspects of the environmental vibration testing that is carried out during the development and qualification of spacecraft. Vibration testing is performed to validate a satellite or equipment’s mathematical model (Finite Element Model) and to prove experimentally that the hardware can withstand without damage the very harsh vibration environment produced during the spacecraft launch.

In reality, during launch the items are shaken in all directions simultaneously and they are mounted on a relatively flexible structure, whereas during the test the vibrations are typically applied one axis at a time, with the items mounted on a rigid interface. Due to the physical mismatch between launch situation and tests, the desire to ensure a conservative test which envelopes the worst case responses produced during launch, produces test conditions which are far more severe than the real launch. The result is that test survival can become a significant load case driving an over-design and therefore preventing an effective optimization of the item with respect to the real operating conditions.

The aim of the research is to investigate these issues and propose methodologies to improve the representativeness of the tests.

For more information or to apply, please contact Prof. Guglielmo Aglietti: g.aglietti@auckland.ac.nz

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Spacecraft deployable structures

Deployable structures are typically used in space application, to enable the launch of equipment whose size in operation in orbit, exceeds the volume available in the launch vehicle. Solar arrays, and antennas are typical examples of structures that are launched in a stowed configuration and deployed once in orbit. However, a more compact launch configuration would be beneficial for a variety of other equipment, such as optical instruments (e.g. cameras / telescopes) which typically utilize large cylindrical elements such as barrels and baffles that could be stowed during launch and deployed to the required size once in orbit.

Telescopic configurations are a typical solution, but there are alternatives, and there is a variety of options available to drive the deployment of such structures. This project will explore novel configurations and techniques that allow compact stowing for launch, and reliable and precise deployment in orbit. The project will include elements of design, development of mathematical models to explore the design space and significant experimental activity.

For more information or to apply, please contact Prof. Guglielmo Aglietti: g.aglietti@auckland.ac.nz

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Development of Radar Systems for Nano-Satellites

Space-borne satellite radar is an important technology to measure properties of the Earth surface. However, existing radar satellites are relatively large, heavy and expensive. Current satellite radar missions employ either only a single satellite platform or a small constellation of two satellites. For these missions the revisit period, i.e. the time between satellite passes over one target region, is often ten days or more. However, it is desirable to observe targets much more frequently. Rapid information can be obtained by using large numbers of satellites that allow one particular region to be overpassed more frequently than with a single satellite. Inexpensive nano-satellites employing commercial-off-the-shelf components are the ideal platform for these constellations.

The small physical size of nano-satellites places significant constraints on the design of radar systems. The miniaturization of SAR systems to fit on a CubeSat requires new technological breakthroughs that go beyond state-of-the-art.

The aim of this PhD project is to develop a novel miniaturised radar front-end suitable for a nano-satellite, particularly focusing on approaches to reduce the number of RF beam-forming chains required and understanding the engineering trade-offs.

Applicants must have a background in electrical/electronics engineering and ideally experience with designing RF circuits.

A tax-free stipend of $NZD 28,200 per year is available for 3 years.

Contact for questions: Andrew Austin, a.austin@auckland.ac.nz

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