Solar Orbiter


Solar Orbiter is a European Space Agency mission to study the Sun and the vast magnetic bubble, called the heliosphere, that the Sun creates. The heliosphere is created by a solar wind that flows out from the Sun in all directions. The solar wind is a rapid expansion of the Sun’s outer atmosphere, producing gusty flows with speeds of between 200km/s to 800 km/s. The Orbiter spacecraft will be put into an orbit around the Sun that is highly inclined to the Earth’s orbit.

History will be made when Orbiter is in place as it will become the closest man-made object to the Sun. At closest approach, Orbiter will be at just over one quarter of the Sun-Earth distance (approx. 0.28 AU or 42,000,000 km) and inside the orbit of the planet Mercury. (In the 1970's and 1980's NASA's Helios probes went as close as 0.29 AU.) At closest approach, Orbiter will give us a view of the Sun with a level of detail never seen before, and will make measurements of the Sun’s outer atmosphere as it expands out into space forming the solar wind and the heliosphere.

What is Solar Orbiter?

Quick information

Expected Launch date  2017

science objective  Understand how the Sun creates/governs the heliosphere

Mission lifetime  6 years+

Agency European Space Agency

orbit Elliptical orbit around the Sun

Links  European Space Agency


             Royal Observatory of Belgium

What science will Solar Orbiter do?

The main aim of Orbiter is to trace and understand the flow of energy that starts at the Sun and flows out driving many processes throughout the Solar System. The energy is carried by magnetic fields and charges particles that flow out from the Sun in the solar wind. The ten instruments on the Solar Orbiter spacecraft will together enable scientists to answer some fundamental questions about how the Sun. For example:

  1. What is the origin of the stream of magnetic field and charged particles that the Sun emits as the solar wind?

  2. How do immense eruptions known as coronal mass ejections evolve as they move out from the Sun?

  3. How are particles, such as protons, accelerated to very high speeds away from the Sun?

All these questions are important for understanding the physics of the Sun and also how the Sun can affect the space environment around the Earth and the other planets. For example, strong gusts in the solar wind, or the arrival of coronal mass ejections at the Earth, can result in strong displays of the aurora but also can also lead to damaging effects on infrastructure such as power grids and satellites.

Orbiter’s ability to look at the poles of the Sun means that it will also be able to study how the polar regions vary. This is important for understanding the long-term changes in solar activity, such as the sunspot cycle, that are driven by a solar dynamo. Recently, the Sun has been through a very quiet time where no sunspots were recorded. Although surprising, it is not unusual for the Sun to do this when its 4.5 billion year history is considered. However, a better understanding of why this happens and the implications for us on Earth is sought.

Ten instruments will be carried onboard Solar Orbiter. Remote sensing instruments will take images of the solar atmosphere and measure the dynamics of the gases over a range of heights in the solar atmosphere. So-called ‘in situ’ instruments will directly measure the particles, electric and magnetic fields and waves in the vicinity of the spacecraft that flow out from the regions being monitored by the remote sensing instruments.

Energetic particle detector

Extreme Ultraviolet Imager



Visible Imager & Magnetograph

Radio & Plasma Waves

Heliospheric Imager

Extreme Ultraviolet Spectrometer

X-ray Imager

Solar Wind Plasma Analyser

Instruments on Orbiter