Effects of Standard and Modified Gravity on Interplanetary Ranges

Abstract

We numerically investigate the impact on the two-body range of several Newtonian and non-Newtonian dynamical effects for some Earth-planet (Mercury, Venus, Mars, Jupiter, Saturn) pairs, in view of the expected cm-level accuracy in some future planned or proposed interplanetary ranging operations. The general relativistic gravitomagnetic Lense-Thirring effect should be modeled and solved for in future accurate ranging tests of Newtonian and post-Newtonian gravity, because it falls within their measurability domain. It could a priori "imprint" the determination of some of the target parameters of the tests considered. Moreover, the ring of the minor asteroids, Ceres, Pallas, Vesta (and also many other asteroids if Mars is considered) and the trans-Neptunian objects (TNOs) act as sources of nonnegligible systematic uncertainty on the larger gravitoelectric post-Newtonian signals from which it is intended to determine the parameters γ and β of the parametrized post-Newtonian (PPN) formalism with very high precision (several orders of magnitude better than the current 10 −4 -10 −5 levels). Also, other putative, nonconventional gravitational effects, like a violation of the strong equivalence principle (SEP), a secular variation of the Newtonian constant of gravitation G, and the Pioneer anomaly, are considered. The presence of a hypothetical, distant planetary-sized body X could be detectable with future high-accuracy planetary ranging. Our analysis can, in principle, be extended to future interplanetary ranging scenarios in which one or more spacecrafts in heliocentric orbits are involved. The impact of fitting the initial conditions, and of the noise in the observations, on the actual detectability of the dynamical signatures investigated, which may be partly absorbed in the estimation process, should be quantitatively addressed in further studies. a See http://meetingorganizer.copernicus.org/EPSC2010/EPSC2010-60.pdf b It is an ESA mission, including two spacecraft, one of them provided by Japan, to be put into orbit around Mercury. The launch is scheduled for 2014. The construction of the instruments is currently ongoing. Int. J. Mod. Phys. D 2011.20:181-232. Downloaded from www.worldscientific.com by TUBITAK NATIONAL OBSERVATORY (TUG) on 02/04/15. For personal use only. c Its cheaper version, ASTROD I, makes use of one spacecraft in a Venus-gravity-assisted solar orbit, ranging optically with ground stations. 16 Int. J. Mod. Phys. D 2011.20:181-232. Downloaded from www.worldscientific.com by TUBITAK NATIONAL OBSERVATORY (TUG) on 02/04/15. For personal use only. 184 L. Iorioand mean equinox of the reference epoch, i.e. J2000.0, centered at the solar system barycenter (SSB); the initial conditions at the epoch J2000.0 were retrieved with the HORIZONS WEB interface by JPL, NASA. The temporal interval of the numerical integration for Mercury and Venus has been taken equal to ∆t = 2 yr, in view of the fact that the typical operational time spans envisaged for the future PLR technique are similar. For Mars and Saturn, f...

General Relativity and Cosmology: Unsolved Questions and Future Directions

“…Astrophysical tests probe gravity from Solar System scales all the way up to galactic cluster scales. They include experiments such as laser ranging off the Moon (lunar laser ranging) and several of the Earth's artificial satellites [372][373][374][375], and proposals to extend laser ranging to other planets in the Solar System (planetary laser ranging) [376][377][378][379][380], radar astrometry on near-Earth objects [381], observations of the precession of the perihelion as well as higher-order effects for Mercury and other planets [338,382,383], observations of spacecraft in the Solar System [337], actual or proposed measurements of the acceleration of the Pioneer [384][385][386] and New Horizons probes [387][388][389], observations of the orbits of compact objects such as neutron stars [390][391][392], and measurements of galaxy rotation curves [393,394]. In the last decade, observations of extrasolar planetary systems have been proposed and used in order to test GR [395][396][397][398][399][400][401][402][403][404].…”

Phenomenology of the Lense-Thirring effect in the solar system

“…An alternative approach to the perihelion precessions consists of looking at the Earth-planet ranges | ρ|, which are, among other things, directly observable quantities 32 . We numerically investigated the solar Lense-Thirring effect on such an observable for the inner planets (Iorio 2010d) by taking the difference between the 32 Recall that the perihelia, like all the other Keplerian orbital elements, cannot be directly measured. perturbed range (| ρ P |) and the unperturbed, reference range (| ρ R |).…”

Scope for a small circumsolar annular gravitational contribution to the Pioneer anomaly without affecting planetary orbits

“…5(b). It is important to understand gravitational effects in the Solar System to very high accuracy with respect to testing general relativity and fundamental physics (Iorio 2011;Iorio 2013b;Nobili et al 2009) and tracking New Horizons is important with respect to constraining a possible massive trans-Plutonian object because of the gravitational effects this could have (Iorio 2013c).…”