The ESA has announced that the solar Orbiter has made its first close approach to the Sun. The event happened on June 15 with the solar Orbiter approaching as close as 77 million km to the Sun’s surface. That is about half the distance between the Sun and Earth. The point that is closest to the Sun is known as the perihelion.
In the week after the close pass, the scientists controlling the mission will test the spacecraft’s ten science instruments, including the six telescopes on-board that will take close-ups of the Sun in unison for the first time. The images will be released in mid-July and will be the closest images of the Sun ever captured.
ESA Solar Orbiter Project Scientist Daniel Muller says that pictures have never been taken from a closer distance than this, but there have been high-resolution close-ups. Those high-resolution close-ups were taken from a telescope in Hawaii earlier this year. The atmosphere between the telescope and the Sun allows scientists only to see a small part of the solar spectrum that can be viewed from space.
ESA scientists also note that the NASA Parker Solar Probe launched in 2018 can approach closer to the Sun than the Solar Orbiter, but the NASA spacecraft lacks telescopes that can directly image the Sun. The NASA Solar Dynamic Observatory does take our resolution images of the sign but does so from a geosynchronous orbit.
The ESA spacecraft is half the distance to the Sun, giving its images twice the resolution of the Solar Dynamic Observatory. The primary objective of the early observations is to prove that the Solar Orbiter telescopes are ready for future scientific observations. The scientists will also analyze data from four in-situ instruments that measure including the magnetic field and particles making up the solar wind.