On April 10 at about 11 a.m. ET (16:00 UTC), a casual radial alignment occurred between the Sun and the two solar probes (Parker Solar Probe and Solar Orbiter).
The Sun: Our mother-star. Credits. NASA/SDO
The two probes dedicated to the study of the Sun were launched with the aim of unraveling as many mysteries as possible about the star that rules the Solar System. This alignment between the star and the probes will make it possible to answer questions that could not be answered by a single search.
The first question to be answered, for example, is how and to what extent solar wind turbulence changes with radial distance.
The Parker Solar Probe: the probe that “touched” the Sun
The Parker Solar Probe (PSP) is a NASA spacecraft launched in 2018 with the primary goal of measuring, observing and understanding the workings of the Sun’s outer corona. PSP will reach the closest distance to the solar “surface” (less than 6 million kilometers) in 2025 at a record speed for a spacecraft: 690,000 km/h!
In addition to these objectives, PSP will also have the delicate task of unraveling some of the mysteries of the solar wind. It is well known that the Sun is often subject to violent explosions, and there is still no method or system capable of predicting the Sun’s activity in advance, which could pose a problem for terrestrial and satellite telecommunications systems.
On 15 December 2021, the PSP “touched” the Sun, penetrating the boundaries of the Sun’s outer atmosphere, the region of space that (we do not know how) reaches 15 million degrees Celsius.
In 2025, the PSP, which will have to withstand temperatures of more than 1,673 K, will pass through coronal holes, which are responsible for the origin of the mysterious solar wind. During these flybys, the PSP will take several ultra-high-resolution images to capture the “surface” of the Sun as never before.
The Solar Orbiter: Europe reaches the Sun
Launched in 2020, the Solar Orbiter (SolO) is a European Space Agency spacecraft designed to study the Sun’s plasma, magnetic field and energetic particles from the solar wind. Because of its proximity to the star, the Solar Orbiter will also be able to gather information about powerful solar flares and how the heliosphere changes when it is passed through by the radiation of these particles, which are still pristine.
A little trivia about the spacecraft: in order to minimize the cost of the entire mission, Solar Orbiter has been equipped with technologies taken directly from the Mercury Planetary Orbiter of another ESA spacecraft: BepiColombo. In fact, the instruments shared by the two spacecraft are the solar panels and the main antenna, both of which have been modified to withstand the high temperatures (> 773 K) of direct sunlight.