ESA’s Jupiter mission launch postponed due to lightning risks

ESA’s spacecraft Juice (JUpiter ICy moons Explorer) has been forced to cancel its planned liftoff due to the risk of lightning, only minutes before its scheduled take-off time. 

The spacecraft was meant to begin today its 8-year journey to Jupiter, to discover whether the planet's three icy moons - Callisto, Europa, and Ganymede - could support life. 

The spacecraft has been loaded with 10 scientific instruments, in what is the ESA’s biggest deep-space mission yet. The 6.6-billion km journey has been supported by British scientists, as well as the UK Space Agency, which has provided £9m of funding for the £1.4bn project. 

The next launch window has been scheduled for 1.14pm BST on Friday, April 14.

The spacecraft was scheduled to lift off on an Ariane 5 rocket on Thursday at 1.15pm UK time from the European spaceport in Kourou, French Guiana.

Responding to the mission's rescheduling, Josef Aschbacher, director general of the European Space Agency, tweeted: “Not what we hoped for, but this is part of the game.

“Hopefully tomorrow we have clearer skies.”

Juice has been built to withstand harsh radiation and extreme conditions, ranging from 250ºC around Venus to minus 230°C near Jupiter. Due to these extreme temperatures, sensitive electronics are protected inside a pair of lead-lined vaults within the body of the spacecraft.

The lightning risks are not the only challenges that scientists will face during Juice's launch. The spacecraft will need to cover a vast distance to arrive at Jupiter, and the Ariane doesn't have the energy to power that journey alone. 

In order to get around this challenge, scientists will leverage Venus and Earth's gravitational forces, and use them to slingshot Juice toward Jupiter. However, in order for this to succeed, both planets will have to be in a very specific position when the launch occurs. 

“We have to use planets – Earth and Venus – just to get to Jupiter,” said Justin Byrne, head of science for Airbus and the mission’s lead contractor. “We will minimise the amount of fuel we need to use by using gravitational support.”

Although the Juice is not seeking to detect life, the spacecraft's findings could help determine whether conditions in the moons' hidden oceans have at least a chance of supporting simple microbial organisms.

Once it arrives in Jupiter's orbit, Juice will perform 35 close passes of the moons - getting to within 400km of their surfaces on occasion - before settling into orbit around Ganymede. There, the spacecraft will leverage innovative equipment to allow scientists to perform a range of tests. 

One of the most important experiments will be the ones carried out by a UK-built magnetometer, which will analyse the properties of the moons' hidden oceans. 

"We'll know the depth of the ocean, its salt content, how deep the crust is above the ocean, and whether the ocean is in contact with the rocky mantle," explained Professor Michele Dougherty, Imperial's magnetometer principal investigator.

"So, we'll get an understanding of the interior structure of the moon, and from observations from other instruments looking at the surface, we'll be able to resolve if there is organic material on that surface."

The probe is expected to arrive at its destination in 2031 and spend three years making detailed studies of Jupiter and three of its largest moons. Once the spacecraft runs out of fuel, Juice will perform a controlled crash into Ganymede, marking the end of its useful life.

In 2011, Nasa launched Juno, a spacecraft tasked with the explicit mission of closely studying Jupiter and its moons. It finally reached the planet in 2016 after a gruelling five-year, 1.4-billion-mile trip, and it has since been unlocking mysteries surrounding the planet and its three moons.