Ultrathin (∼10 nm) carbon foils in space instrumentation

Over the past several decades, a number of groups have successfully developed and flown space instruments based on ultrathin (0.5-3.5 μg cm ^-2 or ∼2-17 nm nominal thickness) carbon foils suspended on fine metallic grids. These foils have proven to be remarkably robust in surviving the rigors of the launch and space environments and have functioned as required over long mission lifetimes. This study examines the scientific basis of possible failure mechanisms and the actual flight histories of ultrathin carbon foils. In all, we were able to document 138 separate foils used in 17 independent space instruments on 16 different spacecraft with a cumulative functioning flight history of 93 foil-years in space. All of these foils clearly survived their launches, and there is no evidence for any significant degradation over their various flight histories. This successful flight heritage, combined with laboratory data on foil survivability, shows that properly implemented ultrathin carbon foils are a mature and reliable technology for space flight applications.