A Pair of Satellites Deliver a Solar Eclipse on Demand

A pair of European satellites have created the first artificial solar eclipses by flying in precise and fancy formation, providing hours of on-demand totality for scientists. The European Space Agency released the eclipse pictures at the Paris Air Show on Monday. Launched late last year, the orbiting duo have churned out simulated solar eclipses since March while zooming tens of thousands of miles above Earth, per the AP. Flying 492 feet apart, one satellite blocks the sun like the moon does during a natural total solar eclipse as the other aims its telescope at the corona, the sun's outer atmosphere that forms a crown or halo of light.

While previous satellites have generated imitation solar eclipses, the sun-blocking disk was always on the same spacecraft as the corona-observing telescope. This intricate, prolonged dance requires the cube-shaped spacecraft, less than 5 feet in size, to have flying accuracy within a mere millimeter, the thickness of a fingernail. This meticulous positioning is achieved autonomously through GPS navigation, star trackers, lasers, and radio links. Dubbed Proba-3, the $210 million mission has generated 10 successful solar eclipses so far, the longest lasting five hours, said the Royal Observatory of Belgium's Andrei Zhukov, the lead scientist for the orbiting corona-observing telescope. He and his team are aiming for a wondrous six hours of totality per eclipse once scientific observations begin.

Scientists already are thrilled by the preliminary results that show the corona without the need for any special image processing. "We almost couldn't believe our eyes," Zhukov said. "This was the first try, and it worked. It was so incredible." Zhukov anticipates an average of two solar eclipses per week being produced for a total of nearly 200 during the two-year mission, yielding more than 1,000 hours of totality. That will be a scientific bonanza since full solar eclipses produce just a few minutes of totality when the moon lines up perfectly between Earth and the sun—on average just once every 18 months. (More space stories.)