LARES/WEBER-SAT and the equivalence principle

It has often been claimed that the proposed Earth artificial satellite LARES/WEBER-SAT-whose primary goal is, in fact, the measurement of the general relativistic Lense-Thirring effect at a some percent level-would allow to greatly improve, among (many) other things, the present-day (10^-13) level of accuracy in testing the equivalence principle as well. Recent claims point towards even two orders of magnitude better, i.e. 10^-15. In this note we show that such a goal is, in fact, unattainable by many orders of magnitude being, instead, the achievable level of the order of 10^-9.Comment: LaTex, 4 pages, no figures, no tables, 26 references. Proofs corrections included. To appear in EPL (Europhysics Letters

PROBING GRAVITY IN NEO'S WITH HIGH-ACCURACY LASER-RANGED TEST MASSES

Received 9 August 2006Communicated by S. G. TuryshevGravity can be studied in detail in near Earth orbits NEO's using laser-ranged testmasses tracked with few-mm accuracy by ILRS. The two LAGEOS satellites have beenused to measure frame dragging (a truly rotational effect predicted by GR) with a 10%error. A new mission and an optimized, second generation satellite, LARES (I. CiufoliniPI), is in preparation to reach an accuracy of 1% or less on frame dragging, to measuresome PPN parameters, to test the

PROBING GRAVITY IN NEO WITH HIGH-ACCURACY LASER-RANGED TEST MASSES

Gravity can be studied in detail in near Earth orbits NEO's using laser-ranged test masses tracked with few-mm accuracy by ILRS. The two LAGEOS satellites have been used to measure frame dragging (a truly rotational effect predicted by GR) with a 10% error. A new mission and an optimized, second generation satellite, LARES (I. Ciufolini PI), is in preparation to reach an accuracy of 1% or less on frame dragging, to measure some PPN parameters, to test the 1/r(2) law in a very weak. field and, possibly, to test select models of unified theories (using the perigee). This requires a full thermal analysis of the test mass and an accurate knowledge of the asymmetric thermal thursts due to the radiation emitted by the Sun and Earth. A Space Climatic Facility (SCF) has been built at INFN-LNF (Frascati, Italy) to perform this experimental program on LAGEOS and LARES prototypes. It consists of a 2 m x 1 m cryostat, simulators of the Sun and Earth radiations and a versatile thermometry system made of discrete probes and an infrared digital camera

The design of lares: A satellite for testing general relativity

The measurement of distance has always been a fundamental issue in science, engineering and astronomy in general. So far, laser ranging has been the most accurate technique for measuring the distance to the Moon and to artificial satellites and can therefore give a significant contribution to measure the tiny effects on orbital parameters due to General Relativity. LARES satellite design and its orbit will be optimized to perform high precision tests of Einstein's theory of General Relativity, in particular the direct measurement of the "frame dragging" effect. The paper will mainly address LARES design issues. Copyright IAF/IAA. All rights reserved