Space flyable Hg+ frequency standards

We discuss a design for a space based atomic frequency standard (AFS) based on Hg⁺ 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⁺ AFS to the present day GPS Cs standards to arrive at the 11 kg mass estimate. The proposed space borne Hg⁺ standard is based upon the recently developed extended linear ion trap architecture which has reduced the size of existing trapped Hg⁺ standards to a physics package which is comparable in size to a Cesium beam tube. The demonstrated frequency stability to below 10^-15 of existing Hg⁺ 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