Pitjeva has also contributed to a better understanding an influence of asteroids and Trans-Neptunian Objects on the planets' motion.Recently Dr. Pitjeva collaborated with Dr. Standish and proposed to the IAU Working Group on Numerical Standards for Fundamental Astronomy (NSFA) the values of the masses of the three largest asteroids, the Moon-Earth mass ratio and the astronomical unit in meters, mainly obtained while fitting the constructed DE (JPL) and EPM (IAA RAS) planet ephemerides.