NASA STEREO-A flies back to Earth after a 17-year journey around the sun

But STEREO-A persisted. And its orbital path around the sun means it has a chance to do what very few other NASA spacecraft can: eventually make its way home.

That came to fruition earlier this month, when STEREO-A passed between the Sun and Earth for the first time since its launch in 2006, NASA said. announce. The flyby was a milestone for the spacecraft and the team that monitored its progress — and a chance for STEREO-A to prove its worth nearly two decades later. As it continues to pass through Earth, STEREO-A will be used to conduct a new search for the Sun, with the help of NASA’s newest satellites in development since its launch.

“This is a point in time for this mission to shine again,” STEREO program scientist Lika Guhatakurta told The Washington Post.

The two STEREO spacecraft were launched in October 2006 with an ambitious mission: to create a 360-degree view of the Sun by observing the star from two vantage points as it orbits that deviate from Earth in opposite directions. STEREO-A orbited the Sun in front of the Earth, and STEREO-B began orbiting the Sun in the opposite direction behind the Earth.

Guathakurta said the difference in perspective was groundbreaking. Ground-based instruments can only spot one piece of the Sun facing Earth at a time, while the rest of the rapidly changing solar surface remains obscured. The twin STEREO spacecraft allowed scientists to do just that Yasser A 360-degree view of the sun for the first time, a still surprising feat in Guathcorta.

“Seeing the sun from the front and from the far side at the same time – extraordinary,” she said. “We’re on planet earth, human, and we’re making it happen.”

STEREO has also allowed scientists to better study the sun’s rocking surface and the hazards erupting from it. The two vehicles, which work in the same way that the eyes create depth perception, provided a 3D view of the sun and of the sun. Coronal mass ejection – a phenomenon in which plumes of plasma and magnetic field shoot outward from the sun’s outer atmosphere at hundreds or thousands of miles per second, potentially threatening Earth’s energy grid and satellites, as well as other planets and NASA spacecraft. These images allowed scientists to track the shape, density and speed of the coronal mass ejection as it ripples through the solar system.

With STEREO-A and STEREO-B still in their orbits, they’ve done just that Come closer The far side of the Sun in 2014. It was a testament to the distance they traveled, but also a huge risk — moving directly behind the Sun would break communication between the spacecraft and NASA for several months.

The two wayward spacecraft, years past their expiration dates, were not designed to operate offline from NASA for long. While conducting tests in preparation for decommissioning, the agency lost contact with STEREO-B. NASA briefly regained contact with the spacecraft in 2016, however determined that a malfunctioning element had sent it into an uncontrollable spin, leaving it unable to properly aim the antenna or solar panels, and the agency abandoned recovery efforts.

However, STEREO-A emerged from the sun’s far side unscathed – and began the long journey back toward Earth. Earlier this month, the spacecraft passed between Earth and the sun, about 5 million miles from Earth, according to NASA.

Guathakurta said the spacecraft came back near Earth just in time. When STEREO-A was launched 17 years ago, it was looking at the sun during solar minimum, a low point in the sun’s 11-year cycle of high and low solar activity. This limited the number of coronal mass ejections and other phenomena initially observed by the spacecraft. STEREO-A’s return this year coincided with a period of intense solar activity.

And his rapid flight means he can finally get back to the work he once did with his missing brother. The agency said a capable fleet of near-Earth satellites and probes will help STEREO-A recreate the 3D imaging of the Sun once taken with STEREO-B.

STEREO-A will continue to work at the edge of solar physics. Scientists hope to use the new data collected during the spacecraft’s flyby for another examination theory Coronal rings — giant arcs of solar material that criss-cross the sun’s surface when viewed in ultraviolet light — may be optical illusions.

For Guhathakurta, who began work on the STEREO mission in 1998, STEREO-A’s perseverance after such a long journey is heartening.

“It’s like seeing your children grow up and do extraordinary things,” Guathakurta said. She added that the STEREO-A mission may not end, depending on NASA’s budget decisions. In either case, STEREO-A will continue on its trajectory in another orbit around the sun.

“They don’t stay at home,” he added with a laugh. “They get away very quickly.”