Space flyable Hg/sup +/ frequency standards

We discuss a design for a space based atomic frequency standard (AFS) based on Hg/sup +/ ions confined in a linear ion trap. This newly developed AFS should be well suited for space borne applications because it can supply the ultra-high stability of a H-maser but its total mass is comparable to that of a NAVSTAR/GPS Cs clock, i.e., about 11 kg. This paper compares the proposed Hg/sup +/ AFS to the present day GPS Cs standards to arrive at the 11 kg mass estimate. The proposed space borne Hg/sup +/ standard is based upon the recently developed extended linear ion trap architecture which has reduced the size of existing trapped Hg/sup +/ standards to a physics package which is comparable in size to a Cesium beam tube. The demonstrated frequency stability to below 10/sup -15/ of existing Hg/sup +/ standards should be maintained or even improved upon in this new architecture. This clock would deliver far more frequency stability per kilogram than any current day space qualified standard.<
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