NASA’s STEREO-A spacecraft comes calling on Earth - after 17 years!

NASA's STEREO-A spacecraft is all set to visit Earth nearly 17 years after launch, but its job is not over yet.

STEREO-A spacecraft will make its first Earth flyby after nearly 17-year-old mission to survey the Sun. (Nasa)

Every year there are various space missions conducted to study the mysteries of the solar system. One such mission was launched by NASA nearly 17 years back to study the Sun. The spacecraft, known as the STEREO-A, collected data and was instrumental in unveiling various discoveries over the years. It had a partner too in the form of STEREO-B craft, but communication was lost with it. Now after 17 years, the STEREO-A spacecraft is rushing towards a rendezvous with the Earth. Notably, NASA has taken this opportunity to make STEREO-A further study the Sun from this vantage point in order to collect new information about our closest star.

About STEREO-A spacecraft

According to NASA reports, the pair of STEREO (Solar TErrestrial RElations Observatory) spacecraft were launched on October 25, 2006, from Florida's Cape Canaveral Air Force Station. The two spacecraft were situated in Sun's orbit, STEREO-A ("Ahead") and STEREO-B ("Behind").

During its early years of operation, the dual-spacecraft mission accomplished its major goal by delivering the first-ever stereoscopic view of our star. On February 6, 2011, another significant milestone was achieved as both STEREO-A and -B reached a remarkable 180-degree separation in their orbits, which gave us the full sphere image of the Sun.

“Prior to that we were ‘tethered' to the Sun-Earth line – we only saw one side of the Sun at a time,” said Lika Guhathakurta, STEREO program scientist at NASA Headquarters in Washington, D.C. “STEREO broke that tether and gave us a view of the Sun as a three-dimensional object.”

Now NASA scientists are looking forward to getting more measurements of the Sun to study the magnetically complex regions. This may also uncover mysteries beyond the mission's reach. Additionally, they plan to investigate a new theory that questions the traditional understanding of coronal loops, which are large arches commonly visible in up-close sun images.

The sun's activity is noticeably increasing as we get closer to the solar maximum predicted for 2025. This has a lot of potential to reveal useful information.