INPOP08, a 4-D planetary ephemeris: From asteroid and time-scale computations to ESA Mars Express and Venus Express contributions

TL;DR

INPOP08 is a comprehensive 4-D planetary ephemeris incorporating asteroid modeling and new ESA spacecraft observations, significantly improving planetary position accuracy and time-scale relations.

Contribution

This paper introduces INPOP08, a new 4-D planetary ephemeris that integrates asteroid modeling and ESA mission data for enhanced accuracy.

Findings

ESA Mars Express and Venus Express data greatly improved planetary orbit fits.

Inclusion of asteroid modeling enhanced ephemeris precision.

Significant impact on Venus, Saturn, and Earth-Moon barycenter orbits.

Abstract

The latest version of the planetary ephemerides developed at the Paris Observatory and at the Besancon Observatory is presented here. INPOP08 is a 4-dimension ephemeris since it provides to users positions and velocities of planets and the relation between TT and TDB. Investigations leading to improve the modeling of asteroids are described as well as the new sets of observations used for the fit of INPOP08. New observations provided by the European Space Agency (ESA) deduced from the tracking of the Mars Express (MEX) and Venus Express (VEX) missions are presented as well as the normal point deduced from the Cassini mission. We show the huge impact brought by these observations in the fit of INPOP08, especially in terms of Venus, Saturn and Earth-Moon barycenter orbits.