The Nanotechnology Centre for Plasma Vapour Deposition in Sheffield Hallam University's Materials and Engineering Research Institute (MERI) develop innovative coatings for a wide variety of applications. They are currently working on coatings for space coolers for space-based astronomy.
- The mesh pictured above is at the heart of the cryocooler, lifting heat off the coolant as it passes through. As part of the flight qualification test, the mesh coated at SHU was folded in two in order to test the strength of adhesion of the coating to the mesh.
I was delighted to read the following from a former colleague of mine at STFC, Dr. Martin Crook from the Space Science Technology Department of Rutherford Appleton Laboratory who said:
“Cryocoolers are a key enabling technology for space based science and astronomy, such as the European Space Agency’s Planck Explorer mission to map out the Cosmic Background Radiation, for which the detectors were cooled to 100mK. STFC’s Rutherford Appleton Laboratory are world leaders in this technology and provided the cryocoolers for part of that cryogenic chain. For some years we have been aware of the potential for rare-earth coatings to enhance the performance of our coolers but despite numerous attempts were not able to implement a flight-worthy solution, however, thanks to the development work carried out by Professor Ehiasarian at Sheffield Hallam University, an excellent coating was realised that is suitable for a flight qualification programme. Directly through that work, our 10-15K Stirling cycle cryocooler has demonstrated a clear advantage over other technologies at this temperature, and is the baseline choice for scientists currently entering instrument proposals for forthcoming missions such as EChO, a space-based observatory to characterise the physics and chemistry of exoplanet atmospheres.”
Prof Ehiasarian and his team have developed a new coating technology called High Power Impulse Magnetron Sputtering (HIPIMS) for deposition of very dense and highly adherent metal and ceramic materials. The team is world leader in HIPIMS both understanding the fundamental physics of the process and developing new applications for space, manufacturing, automotive, semiconductor and photovoltaic sectors.
Cryocooling of space satellites is crucial due to the low thermal conductivity of the vacuum operating environment and the necessity to cool vital systems such as detectors, optics, and body. RAL have been involved with the development of miniature cryocoolers for space applications at the outset of the technology in the 1980’s and have successfully developed cryocooler designs which have been flown on many European Space Agency missions. As part of our continuing development we are currently focusing on improving the performance of our Stirling cycle cryocoolers by increasing the effectiveness of the low temperature regenerator inside these closed cycle coolers. Miniature cryocoolers have been widely used in satellites since the 1980s due to their small size and ability to reach low temperatures of < 10k. However, the increasing complexity of satellites demands improvements in cooling efficiency.
The Exoplanet Characterisation Observatory, EChO, will be the first dedicated mission to investigate the physics and chemistry of Exoplanetary Atmospheres. It will place our Solar System in context and by addressing the suitability of planets for life will allow us to address some of the fundamental questions of the Cosmic Visions programme:
•What are the conditions for planet formation and the emergence of life?
