The European Space Agency launched two satellites last week that can create “solar eclipses on demand” in an effort to better understand the sun.
The Dec. 5 launch from India “has the potential to change the nature of future space missions,” the agency said and aims to help scientists advance their study of space weather.
The two satellites on the Proba-3 mission were launched together and separated just under 20 minutes after takeoff. The spacecraft will maintain “a fixed configuration as if they were a single large rigid structure in space, to prove formation flying and rendezvous technologies,” the agency said.
Daniel Seaton, a co-investigator on Proba-3 and a solar physicist at the Southwest Research Institute, told The Washington Post the movements of the satellites must be extremely precise—within a millimeter—for the experiment to work.
“Think about standing at one end of a football field and landing a pass on a penny at the other end; that would be easy compared to what they’re doing here,” Seaton said.
The satellites will align precisely in orbit to create the artificial eclipse, with one spacecraft casting a shadow onto the other from 150 meters away.
“The shade provided by the first spacecraft will cover the fiery face of the Sun so that its faint surrounding ‘coronal’ atmosphere becomes visible,” mimicking an eclipse, the agency said. “The enigmatic corona – much hotter than the Sun itself – is where space weather originates, a topic of widespread scientific and practical interest.”
These on-demand solar eclipses can last up to six hours, enabling scientists to conduct research without flying around the world chasing eclipses to study them.
If successful, the technology could be scaled up to larger satellites that could block out more starlight and help scientists search for planets, according to Seaton.