The information on the accuracy of harmonic coefficients C1m, S1m as about a non-monotonic function of order m has been obtained from analysis of standard deviations of athe lumped coefficients compited from standart deviations of harmonic coefficients of various recent Earth gravity models as well as from resonant solutions for the individual orders. It is shown that the acuracy is lower for 8< m < 11 than for 12 < m < 15.
A draft of new laser geodynamic twin-satellite is presented. The aim of the experiment, theoretical basis and suggestions to orbit selection - with ~8 to 11 revs. „day^-1 - are described; some comments to a possible design of the satellites and to their separation are also given.