NASA's space craft had invaded the un explorable region in our solar system called as out side air of the sun,The corona.It was reached in April but announced on December.The long awaited milestone is a major achievement of the Parker solar probe.A vehicle which is closer to the sun than any other missions to date 

“We have finally arrived,” said Nicola Fox who is the directer of heliophysics at NASA's washington DC headquarters."Humanity has touched the sun." 

In many respects,The Parker solar probe is the counter points of NASA's twin voyager space craft. In 2012,Voyager 1 travelled near to the sun to become the first face craft for reaching sun and this was the mission to leave the solar wind dominated territory of the universe,the flood of energy particles comming from the sun. The Parker probe is closer than ever to the center of solar system and flying head on to the solar wind and our star atmosphere. Scientist were asked the biggest unanswered questions that how the corona of the sun reached to its extreme temperature above the surface of the sun.

Parker reached the sun at 09:33 UTC on 28th April. It tools several months to download and analyse the data collected by Parker solar probe and to confirm that the Parker crossed a long awaited boundry known as the Alfven surface. This surface shows the interface between the sun's atmosphere and the outer region of the universe dominated by the solar wind. 

The Parker probe passed through a through a pseudostreamer of charged materials as it passed through the surface of the Alfven waves.While the space craft is in the corona it studied about the anomalous twist of the solar wind magenetic field known as serpentine, scientist already knew about the serpentine but,this Space craft helped them a lot to find out the Orgin of serpentine to the surface of the sun.

It cost 1.5 billion U.S dollars to creat this space craft and it has been orbiting the sun since 2018. When it reaches very closer to the sun the carbon fiber layered heatsink protects the equipment of this Space craft from the surface temperature of the sun 1370 degree 

The missions closest approach is scheduled for 2025 when it will be only 6.2 million kilometres from the solar surface well within the orbit of mercury while each visit will continue to reveal new information about corona.