ALD in space

Early on Saturday 17 November 2018, an Antares rocket will launch from NASA’s Wallops Island Flight Facility for a resupply mission to the International Space Station. Aboard the Cygnus cargo vessel is MISSE-10, a materials science experiment that will expose a range of material samples to the surprisingly active environment of low Earth orbit (LEO) for over one year in space; the samples then will be returned to Earth for further evaluation.

Waste heat from the ISS is radiated to space by the large white panels seen in the top image. The pigment used to coat these radiators is designed for optimal emission of waste thermal radiation and minimal absorption of solar radiation. Because the (electrically) insulating pigment can become differentially charged in LEO, our group has been working in conjunction with NASA’s Goddard Space Flight Center to develop ultra-thin conductive coatings that do not interfere with the optical properties of the pigments and allow for the dissipation of static charge.

 Conductive thin films (less than 100 atoms thick)  of indium oxide (IO) and tin-doped indium oxide (ITO) were deposited by atomic layer deposition (ALD) on the pigment nanoparticles to create four samples that will be flown on this mission (an earlier MISSE mission image is seen in the center image; details of our mission are described in the Innovative Coatings Experiment). With the support of NASA and NSF, a special ALD reactor for depositing the IO and ITO films (bottom image) was constructed and then used by Hossein Salami, Alan Uy, Aarathi Vadapalli, and Corinne Grob of our research group, in conjunction with group alumnus Dr. Vivek Dwivedi, Associate Head of the NASA GSFC  Thermal Engineering Branch.

Additional information can be found in the ISR news story as well as the ChBE news.

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