Europe's mission to the icy moons of Jupiter has blasted away from Earth.
The Juice satellite was sent skyward on an Ariane-5 rocket from the Kourou spaceport in French Guiana.
It is second time lucky for the European Space Agency (Esa) project after Thursday's launch attempt had to be stood down because of the weather.
The Jupiter Icy Moons Explorer (Juice) is being sent to the largest planet in the Solar System to study its major moons - Callisto, Ganymede and Europa.
These worlds are thought to retain vast reservoirs of liquid water.
Scientists are intrigued to know whether the moons might also host life.
This might sound fanciful. Jupiter is in the cold, outer reaches of the Solar System, far from the Sun and receiving just one twenty-fifth of the light falling on Earth.
The ice-covered Callisto, Ganymede and Europa were discovered by the Italian astronomer Galileo Galilei in 1610, using the recently invented telescope. He could see them as little dots turning about Jupiter. (He could also see a fourth body we now know as Io, a much smaller world covered in volcanoes).
The icy trio range in diameter from 4,800km to 5,300km. To put this in context, Earth's natural satellite is roughly 3,500km across.