A NASA spacecraft flies over Earth for the first time in 17 years

For the past 17 years, the Stereo-A spacecraft has been tracking Earth as it orbits the sun. Now the probe has caught up with its home planet, overtaking Earthers on the cosmic trajectory and making its first short rendezvous with Earth since its launch on October 25, 2006.

like stereo spacecraft When the Sun was closest to Earth in 2006, it was in solar minimum: a phase of low activity in an 11-year cycle. Now the sun is approaching solar maximum – Stereo-A will experience a fundamentally different sun at this point in the solar cycle.

The STEREO (Solar Terrestrial Relations Observatory) mission originally started with two space probes: Leading Stereo-A (to advance) and – if you say A, you should also say B – Stereo-B. This lags stereo probe a.

In 2014, the Stereo-A probe loses its partner and is forced to fly on its own: Stereo-B has gone silent after a planned reset. But don’t panic for those who already feel sorry for Stereo-A – the next time he flies, he’ll be teaming up again.

The two spacecraft provided the first stereoscopic view of the Sun. Over time, the two probes became 180 degrees apart in their orbits – allowing for the first time a simultaneous view of the star as a perfect sphere.

“Before, we were ‘locked’ to the helio-Earth line – only seeing one side of the sun at a time,” says Lica Guathacorta, stereo program scientist at NASA. in the current situation. With the help of a stereo probe, it is possible to go beyond these limits and capture the sun as a 3D object.

The probe will share their views with The Sun and Heliospheric Observatory (SOHO)a joint mission between NASA and the European Space Agency, and Solar Dynamics Observatory (SDO) NASA share. Collaboration between solar missions enables what is called a “stereoscopic view” of the sun.

This is the physiological process of spatial perception of an object with both eyes, resulting in three-dimensional perception, which is also known as depth of field.

The team behind the STEREO mission also hopes to test a theory about coronal rings. In solar physics, a coronal ring is a well-defined arc-like structure in the solar atmosphere. They are often associated with the strong magnetic fields found in active regions and sunspots.

“There was a recent idea that coronal rings might just be an optical illusion,” says Terry Kuchera, stereolithography project scientist at NASA’s Goddard Space Flight Center. Some scientists believe that due to the limited angle of view, the rings have shapes that they do not actually have.

Viewing the coronal rings from different angles should shed some light on this theory.

The Stereo-A system not only provides information about what phenomena it can see while flying over the Earth, but also information about what it “feels” when doing so. And here we are not talking about the loss of Stereo-B. Because when a cloud of solar material, called a coronal mass ejection (CME), hits Earth, it can disrupt satellite and radio signals or even cause spikes in the power grid.

To understand how the CME’s magnetic field has evolved on its way to Earth, researchers are creating computer models of these solar flares and updating them with new observations from the spacecraft. Typically, scientists only have one or two spacecraft next to each other that can make these measurements.

In the months leading up to and after the Stereo-A flyby, all CMEs pointing toward Earth will fly by Stereo-A and other near-Earth spacecraft, allowing scientists to make much-needed multipoint measurements from within the CME.