urope’s Solar Orbiter, which has been launched to study the hidden mysteries of the Sun and its connection to space weather, is set to return to Earth before kick-starting its main science mission. The solar orbiter is returning to Earth for a much-needed flyby to go deeper towards the Sun.

However, to successfully conduct the flyby, the spacecraft will have to manoeuvre through the debris field surrounding the planet, which will be a risky business for engineers monitoring it from the ground. The flyby will take place on November 27 with the spacecraft passing just 460 km above North Africa and the Canary Islands, coming as close as the orbit of the International Space Station.

The European Space Agency (ESA), which flies the spacecraft, said that the flyby is essential to decrease the energy of the spacecraft and line it up for its next close pass of the Sun. “But, it comes with a risk. The spacecraft must pass through two orbital regions, each of which is populated with space debris,” ESA said in a statement.

The spacecraft will have to pass through two major phases, a geostationary ring of satellites at 36,000 km and the collection of low Earth orbits at around 400 km.

CRUISE PHASE COMPLETE

The flyby will mark a major milestone for the spacecraft, which was launched in February 2020 towards the Sun, the completion of its cruise phase. The spacecraft entered its commissioning phase after launch during which scientists tested its instruments and the cruise phase began in July 2020.

During this phase, the orbiter has been conducting scientific studies around solar wind while gathering data on conditions around the probe, while the remote sensing instruments designed to look at the Sun have been in their extended calibration and characterisation mode.

The orbiter has been sending more data than expected back to Earth, and more than fifty papers detailing the Solar Orbiter’s cruise phase science results are to be published in December by the journal Astronomy & Astrophysics.

SCIENCE PHASE TO BEGIN

As the orbiter heads back towards the Sun after its November 27 flyby with Earth, engineers will turn on its two science instruments. The orbiter will make a close pass, to the Sun in March, going within 50 million kilometres of the biggest star in our solar system. “This will be at a third of the distance between the Sun and Earth. So compared to all the interesting high resolution images that we’ve already gotten everything now will be zoomed in by about a factor of two,” Daniel Müller, Solar Orbiter Project Scientist said.

The orbiter will provide a fresh glimpse into the enigmatic campfires that the Solar Orbiter saw at the first perihelion, which could hold answers to a mysterious phenomenon observed on the Sun. While the outer atmosphere of the Sun has a temperature of millions of degrees, the surface has a temperature of thousands which seemingly defies laws of physics because heat should not be able to flow from a colder to a hotter object.

NOT WITHOUT STUDYING EARTH

While the science phase will take the spacecraft back towards the Sun, the flyby with Earth will offer a unique advantage to scientists studying the planet’s magnetic field. It is the magnetic field that interacts with solar wind hurtled by the Sun, resulting in auroras on the poles.

Scientists want to study the interaction between the solar wind and the magnetic field of the planet. Not only can particles from the solar wind penetrate the magnetic field and spark the aurora in our skies, but atoms from our atmosphere can also be lost into space.

“This flyby is exciting: seeing what the Solar Orbiter sees in our part of space, and how that compares to what we are seeing, and if there are surprises, what are they?” Anja Strømme, Swarm Mission Manager said.

Meanwhile, people on Earth will have one final chance to bid farewell to the orbiter before its heads back to the Sun. The ESA said that during its closest approach, skywatchers in the Canaries and North Africa could catch a brief glimpse of the spacecraft speeding through the sky.