Launch & Orbit

The orbit of the Solar Orbiter mission is designed to bring the scientific payload to a unique "view point" where in situ and remote sensing instruments will make unprecedented scientific measurements of the state of the solar corona and the inner heliosphere.

Although the precise orbit parameters depend on the launch date, these minimum features are common to all the launch scenarios:

• the perihelion distances down to about 0.22 AU,
• the aphelion distances up to 0.7 AU,
• an inclination of about 35 degrees (in the later phase of the mission),
• a mean orbit of about 150 days,
• a transfer phase of about 3.5 years before the nominal orbit of the mission is reached,
• a mission duration (between launch and ending of any operation) of about 10.5 years, roughly a full solar cycle.

The EUI instrument carries two sets of EUV telescopes: the FSI (Full Sun Imager) will be used throughout the mission lifetime to monitor the activity of the whole corona, while near perihelion, the HRIs (High Resolution Imager) will produce images of the corona at unprecedented spatial resolution.

The launch of Solar Orbiter is foreseen from the Kourou spaceport, between 2013 and 2018 with a Soyuz rocket equipped with a Fregat upper stage. Each envisioned launch scenario is made of three periods which are defined by the achievement of a given scientific goal:

• The nominal mission encloses the transfer phase which lasts about 3.5 years. Scientific operations start during this phase. It ends at End of Nominal Mission (ENM) after the fourth Venus flyby. At this time, the probe has reached a significant inclination above the ecliptic plane.
• The extended mission phase ends when the inclination of the orbit has reached the maximum value feasible. In practice the End of eXtended Mission (EXM) coincides with the sixth Venus flyby.
• The End Of the Mission (EOM) coincides with the end of an additional extension period. To avoid any possibility that the probe would crash on Venus, the last Venus flyby will send the spacecraft onto a non-resonant orbit.