Abstract:
We discuss a design for a space based atomic frequency standard (AFS) based on Hg<SUP>+</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 cesium clock, i.e., about 11kg. This paper will compare the proposed Hg<SUP>+</SUP> AFS to the present day GPS cesium standards to arrive at the 11 kg mass estimate. The proposed space borne Hg<SUP>+</SUP> standard is based upon the recently developed extended linear ion trap architecture which has reduced the size of existing trapped Hg<SUP>+</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</SUP> of existing Hg<SUP>+</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.
