Solar orbiter: a short review of the mission and early science results

Abstract

On 9 February 2020 at 11:03 pm EST, an Atlas V 411 rocket launched the ESA/ NASA Solar Orbiter mission. This mission was the culmination of decades of work across many countries to achieve the goal of getting close to the Sun and measuring how the Sun creates and maintains the heliosphere. The mission’s goal is to understand how the inner heliosphere works and how solar activity impacts it. The spacecraft achieves this with a specially designed highly elliptical orbit that gets close to the Sun twice a year. It reaches as close as 0.28 au requiring a novel heat shield to protect the instruments from the intense heat (the front side of the heat shield reaches around 500 ^∘C at this location). There are ten scientific instruments onboard: Six remote-sensing instruments observe solar activity across the electromagnetic spectrum on small and large scales, including imaging the source regions of the solar wind. They are accompanied by four in-situ instruments to probe the properties of the solar wind as it flows past the spacecraft. This review paper describes a selection of results from Solar Orbiter during its cruise phase and the beginning of its nominal scientific operations phase, and looks towards the next phases of the mission, when the spacecraft leaves the ecliptic plane to observe the solar poles for the first time.