The Solar Orbiter (SolO) is a Sun-observing satellite, developed by the European Space Agency (ESA). SolO is intended to perform detailed measurements of the inner heliosphere and nascent solar wind*, and perform close observations of the polar regions of the Sun, which is difficult to do from Earth to answer the question :How does the Sun create and control the heliosphere?
SolO was launched in February 2020. The mission is planned to last 7 years.It was selected as the first medium-class mission of ESA's Cosmic Vision 2015-2025 Programme.
Objective and details of Mission
Solar Orbiter will be used to examine how the Sun creates and controls the heliosphere, the vast bubble of charged particles blown by the solar wind into the interstellar medium. It will operate both in and out of the ecliptic plane. Solar Orbiter will measure solar wind plasma, fields, waves and energetic particles close enough to the Sun to ensure that they are still relatively pristine.
During the nominal mission, Solar Orbiter will view the Sun from latitudes of up to 25°. This will enable the instruments to image the polar regions of the Sun clearly for the first time and make key measurements that will advance our understanding of the solar dynamo and the polarity reversal of the global magnetic field.
The spacecraft will make a close approach to the Sun every five months. Around closest approach, when travelling at its fastest, Solar Orbiter will be positioned for several days over roughly the same region of the solar atmosphere, as the Sun rotates on its axis.
Solar Orbiter is an ESA-led mission with strong NASA participation. There will be ten instruments on board, eight of which will be provided by Principal Investigators through national funding by ESA Member States.
*The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma mostly consists of electrons, protons and alpha particles with kinetic energy between 0.5 and 10 keV.