The launch of a spacecraft on a mission to explore Jupiter and three of its moons has been postponed until Friday due to a lightning risk.
Juice - short for Jupiter Icy Moons Explorer - was set to launch at 1.15pm on Thursday on an eight-year mission to reach the giant planet’s major moons, Callisto, Europa and Ganymede.
Scientists hope the probe searching the icy moons will help find out whether they could have supported life.
Arianespace, which developed the Ariane 5 rocket to carry the European Space Agency's Jupiter Icy Moons Explorer (Juice), said on Twitter on Thursday that the launch has had to be postponed due to a risk of lightning at the scheduled lift-off time from Europe's Spaceport in French Guiana.
"The Ariane 5 launch vehicle and its passenger Juice are in stable and safe condition”, it said.
The next launch window is expected to be at 1.14pm BST on Friday.
Liquid water, a source of energy and nutrients are the three things scientists believe are necessary for life to emerge anywhere in the universe.
There is evidence that the moons hold oceans of liquid water at depth. Ganymede is the primary target for exploration as it is the only moon in the solar system to generate its own magnetic field.
Scientists told reporters at a briefing on Thursday morning: “Our main question is whether we could find habitable places within the Jupiter system.
Learning more about Jupiter will tell us more about our solar system and other systems.”
The €1.6bn (£1.4bn) mission is set to launch on an Ariane-5 rocket from Kourou, French Guiana.
It will separate from the upper stages of the rocket at 1.42pm UK time, and should send its first signal down to the Earth’s surface by 1.51pm, allowing mission crews to take control of the craft.
The spacecraft will be despatched on a path around the inner Solar System where a series of flybys of Venus and Earth will gravitationally ‘sling’ the craft to its destination.
It is not expected to arrive until summer of 2031. There will then be another eight years of collecting data and then analysing it.
The spacecraft is packed with various cameras, particle detectors, a radar to map sub-surface features, and a magnetometer - which will be used to discover more about the moons’ hidden oceans.
Scientists will also closely monitor Jupiter itself, with astrononers hoping that the knowledge gained about its complex environment will inform studies of other gas giants.
Among these is Saturn, which also has moons with oceans.
The European Space Agency is being supported in its work by Nasa, and the space agencies of Japan and Israel.
