ESA’s Solar Orbiter reaches closest point to the sun
The European Space Agency’s Solar Orbiter will reach its first perihelion on Monday, the point in its orbit at which the probe comes closest to the sun. It is the first time that a probe with a camera has taken such close-up pictures of the sun.
Upon reaching perihelion, the Solar Orbiter will pass the sun at 77 million kilometers, which is about half the distance from Earth to the sun. In the coming week, ESA technicians will test the scientific instruments, including the six telescopes present. They will jointly take close-up images of the sun for the first time. The purpose of this is to see if the instruments are suitable and ready for future scientific observations. Data from other instruments that look at, among other things, the magnetic field and the solar wind will also be examined.
According to the ESA, no images of the sun have been taken at this relatively close distance before. The images will be published in the middle of next month. It takes about a week to download all images from during perihelion, which is happening with the antenna installation in Malargüe, Argentina. They are then processed to be published sometime in mid-July. The data from the other sensors will follow later this year, because they still need to be calibrated.
NASA’s Parker Solar Probe, launched in 2018, also orbits the sun, passing the sun at even shorter distances, but it doesn’t have telescopes onboard that can focus directly on the sun. The images from the European probe are somewhat similar to NASA’s Solar Dynamic Observatory, which orbits the Earth. Because the Solar Orbiter is currently 134 million kilometers from Earth and much closer to the sun, the resolution of the European probe’s images is twice that of the Solar Dynamic Observatory.
The Solar Orbiter launched on February 10 and will eventually pass the sun at a distance of 42 million kilometers. In comparison, Mercury orbits the sun at a distance of about 46 to 70 million kilometers. The next perihelion will follow in early 2021. Eventually, the Solar Orbiter will change its orbit with the help of the gravity of Venus in order to also be able to view the poles of the sun. That should help scientists better understand the behavior of the sun’s magnetic field.