ESA Science & Technology - SMART-1 Osculating Orbit up to 25.08.04

In this diagram the osculating orbits at launch (GTO) and at different times are plotted. The large effects on the orbit expansion, that the combination of the operations of the electric propulsion together with the Moon encounter have, are clearly visible. The Moon effects are mainly in the increase of the perigee altitude and in the rotation of the line of apsides (change in argument of perigee).

Since the start of the mission the orbital elements have been changed by the ion-engine and the first lunar resonance as follows:

• The semi-major axis from 24 626 km to 139 307 km
• The perigee altitude from 656 km to 31 413 km
• The apogee altitude from 35 880 km to more than 230 000 km
• The orbital period from 10 hours 41 minutes to nearly 6 days