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Department of Physics

The Cavendish Laboratory
graphic illustration of satellites orbiting around Earth

Unsuccessful landings are the main obstacle to the success of most space missions; this comes at a great economic cost (e.g., NASA’s Genesis rough landing). Furthermore, the quantity of space debris surrounding Earth keeps increasing very fast: there are already approximately 34,000 objects greater than 10 cm, and 128 million objects of 1 mm to 1 cm.

In orbit, a collision of just a 10 cm object on a spacecraft/satellite can disintegrate it into thousands of fragments due to the high impact velocities present in space: ~15 km/s for space debris and ~72 km/s for meteoroids. Therefore, collisions in orbit can produce thousands of small and fast-moving fragments of debris that can destroy, for example, a functioning satellite. The socio-economic consequences of these impacts from the debris can be severe because important space applications are lost, such as weather forecasting, climate monitoring, and space-based communications.

Marlini Simoes, during her PhD at the Cavendish Laboratory, found some headway through her research in 3D Printing Smart Cellular Materials: Self-healing Protection for Space Applications, which was funded by EPSRC and The European Space Agency.

Her research, for which she has won the UK Doctoral Researcher Awards, can be applied in reusable energy absorbers for vehicle landing impacts, and to offer self-healing protection against space debris impact. The architecture/geometry of cellular materials plays a dominant role in the mechanical performance of the material structures, relative to the additively manufacturing process parameters used. During her research, she manufactured a light metallic cellular structure that can recover up to 70% of their original shape after having been significantly deformed/impacted. This was considered a long-standing challenge due to the high sensitivity of the smart material used (shape memory alloys) to the temperatures involved in additive manufacturing processes. During her research she has also developed a new computational formulation that uses the phase field model to predict fracture and fatigue in shape memory alloys.

These findings can be utilised in space applications, where there is a demand for high-performance but light-weight materials with significant energy absorption to mitigate against impacts. Even beyond space applications, her project can potentially be a game-changer for other sectors such as automotive crashworthiness, structural blast protection, and to any other applications where impact protection is sought.

Marlini Simoes earned a Dual Bachelor Degree with Honours in Mechanical Engineering and Materials Science + a Master's from the University of Birmingham, UK, and McGill University in Canada. Marlini Simoes graduated with the highest final marks in her cohort and received many prizes during her studies such as the Best Student Certificate Award from the Institution of Mechanical Engineers of the UK.  After graduation, she joined the University of Cambridge for her PhD studies. During her PhD, Marlini Simoes was awarded a STEM for Britain Medal in the Engineering category, and she was a Finalist in the Robert J. Melosh Medal competition (USA) for the best paper in Finite Element Analysis.

Her latest recognition  - The UK Doctoral Researcher Awards -is a UK wide academic competition which is awarded annually to junior researchers who are pursuing doctoral degrees in the UK. Upon learning about her award Marlini reacted, “This award recognises my pioneering contributions to the areas of additive manufacturing, materials engineering and computational mechanics. I feel very happy and honoured about this, and very motivated to continue doing more science. I would like to thank you my collaborators from Renishaw Iberica, IMDEA Materials, FADA-CATEC, University of Birmingham, Technical University of Denmark, Imperial College of London, and TU Delft, and also a big thank you to Dr Chris Braithwaite.”

Image Credit - Marlini Simoes