Space science took a new step forward as the European Space Agency (ESA)’s Solar Orbiter traveled closer to the sun than any other spacecraft in history. In June, the Solar Orbiter reached 48 million miles from the sun’s surface, making its first close pass of the sun. The Solar Orbiter launched from Cape Canaveral, Florida, at 11:03 p.m. EST on Sunday, February 9, 2020, as part of a joint mission between the National Aeronautics and Space Administration (NASA) and the ESA. This is the first mission in this global space collaboration.
Being the first of its kind, this mission will produce images of the north and south poles of the sun using six telescopes on board to capture the spacecraft’s view. The importance of having a visual understanding of the sun’s poles is that it can provide more information about the sun’s powerful magnetic fields. These magnetic fields affect Earth in numerous ways, including space weather, which affects networked systems like the Global Positioning System (GPS), communications, and astronauts on the International Space Station (ISS). To take these images, the Solar Orbiter must be at a distance close to the sun.
The spacecraft’s first perihelion, the point nearest to the sun in the path of an orbiting celestial body (such as a planet), was about half the distance between the Earth and the sun. Daniel Müller, the ESA’s Solar Orbiter project scientist, reported the closest approach of the probe to be around 3:35 a.m. EST. Since then, the spacecraft advanced to the “cruise” phase of its mission, in which it will travel even closer to the sun’s surface--around 26 million miles closer than Mercury. This distance will allow the Solar Orbiter to make never-before-seen observations of the sun that would be impossible from a farther distance.
“We have never taken pictures of the sun from a closer distance than this,” Müller said. He added that images taken during this mission will be released this summer.
Equipped with ten instruments, the Solar Orbiter can acquire observations of the sun’s corona (or atmosphere), its poles and solar disk, and the circular visible surface of the sun. It can also capture measurements of the sun’s magnetic fields, solar wind, or energized stream of particles that are released by the sun and travel across our solar system. The sun’s magnetic fields stretch beyond Pluto, allowing solar wind to travel directly across the solar system. These observations would not be possible without the advanced instruments aboard the spacecraft.
"Our ultraviolet imaging telescopes have the same spatial resolution as those of NASA's Solar Dynamic Observatory (SDO), which takes high-resolution images of the sun from an orbit close to Earth. Because we are currently at half the distance to the sun, our images have twice SDO's resolution during this perihelion," Müller said in a statement.
The spacecraft has four instruments physically exposed to the outside environment, which will be fully operational when the Solar Orbiter arrives at its closest point to the sun, and will measure the properties of solar wind along its path. These four instruments provide a way to “touch” the environment around the spacecraft, while the other six provide remote sensing.
"After one final swing-by at Earth in November 2021, Solar Orbiter will get closer to the sun than Mercury, our innermost planet," Müller told CNN. "The mission will then use Venus' gravity repeatedly to leave the ecliptic plane of the solar system and ultimately image the sun's uncharted polar regions for the first time.”
With the discoveries made by the Solar Orbiter, we’ll be able to better understand space weather, something that affects us every day, and scientists will have more knowledge about the sun than ever before.
[Sources: CNN; NASA; ESA]