A satellite built by Airbus in Stevenage to orbit the sun has taken off from Cape Canaveral in Florida.
The satellite will take the first ever pictures of the sun's poles.
The spacecraft will make a close approach to the Sun every five months; at its closest approach Solar Orbiter will only be 42 million km away- that's closer than the planet Mercury.
It will be positioned for several days over roughly the same region of the Sun's surface, as the Sun rotates on its axis.
It means it will be able to observe the magnetic activity building up in the atmosphere that can lead to powerful flares and eruptions.
The European Space Agency says its mission will revolutionise the understanding of the sun and how it influences the planets around it.
The Stevenage built orbiter will have to endure temperatures of more than 500°C- that's hot enough to melt lead. Its heat shield, with a coating called SolarBlack, will continually face the Sun, protecting the sensitive instruments behind it, some of which still require heaters to keep them warm and at operating temperature.
Speaking before the launch Ian Walters from Airbus said everyone was excited...