Solar Orbiter, an ESA mission with contribution from NASA, was launched on 10 February 2020 to study the Sun, the inner heliosphere and the solar wind. It hosts a suite of instruments to make both in-site and remote-sensing measurements. Over the last few years, these instruments have helped space weather forecasters in monitoring, analyzing and forecasting drivers of space weather. Typical examples have been discussed in STCE newsitems such as on the intensity of solar flares (STIX; e.g. here), the propagation of interplanetary coronal mass ejections and energetic particles (resp. MAG and EPD; e.g. here), and of course the Extreme Ultraviolet Imager EUI that helped with the identification and evolution of solar eruptions (e.g. here, here, and here). A portion from a high-resolution solar image taken by EUI can be found underneath (ESA). This snippet is not even fully zoomed-in!
Nonetheless, Solar Orbiter is in the first place a science mission. SolO's instruments have already made many important scientific discoveries and contributions. Hence, early 2023, ESA started a webpage with short informative texts based on a topic related to the use of Solar Orbiter data and answering some of the fundamental questions in solar and space physics. These nuggets are very similar to the format used by Hugh Hudson for the Yohkoh and then Rhessi newsitems, now called SolarNuggets. The Solar Orbiter science nuggets recently celebrated their 50th nugget and fittingly dedicated it to the many contributions made in the field of solar and heliospheric physics. Indeed, Solar Orbiter has certainly advanced our knowledge in the domain of
- solar coronal heating (remember campfires?),
- the origins of the solar wind (remember the magnetic switchbacks?),
- solar flares, CMEs and space weather (remember e.g. the picoflare jets?), and
- particle acceleration in the heliosphere (i.e. on Solar Energetic Particle (SEP) and Energetic Storm Particle (ESP) events).
Very often, the results could only be obtained by an intense collaboration between several spacecraft such as with the Parker Solar Probe, Hinode, SDO and STEREO-A. Mid-February 2025 ( ), Solar Orbiter started its first gravitiational manoeuvres to get into a somewhat more inclined orbit around the Sun (17 degrees; ESA), the purpose being to get a better view of the Sun's poles. By the end of the nominal science phase (already in December 2026!), the inclination should be about 24 degrees. If the mission gets extended, the inclination will be further increased to 33 degrees. That would hold the promise of a fascinating sight and many more discoveries to come!
