The probe will go to the outskirts of the solar system
European space scientists will try to carry out one of the most daring operations ever undertaken in interplanetary flight. On Wednesday, they will send their probe to explore Jupiter's icy moons (Juice) to flyby Earth and its moon and perform the first dual-gravity maneuver in space.
The complex and high-risk undertaking is vital to the success of the European Space Agency's (ESA) mission and aims to deliver the €1.6bn robotic craft to its target, Jupiter, by July 2031, The Observer reports. There, it will begin exploring the giant planet's two moons, Europa and Ganymede, in an attempt to find signs of life that might lurk in their icy oceans.
But the manoeuvre will require extremely precise navigation. The slightest error could send Juice off course and ruin the mission, ESA warned. “It’s like driving through a very narrow corridor, very, very fast: you press the accelerator to the floor when the distance to the curb is only a few millimetres,” said Ignacio Tanco, Juice’s spacecraft operations manager.
The craft's graceful celestial dance will begin on Wednesday when it passes the Moon and then zooms towards Earth, using their gravitational fields to change its speed and direction as it flies past the two objects and heads into the inner solar system. Then there's a flyby of Venus next year, followed by two more flybys of Earth in 2026 and 2029, before Juice finally heads for Jupiter.
It's an unusual interplanetary mission, which will require Juice to move at the right speed, at the right time and in the right direction for each encounter, The Observer notes. But without such precision manoeuvring, space engineers simply wouldn't be able to explore planets further from the Sun, ESA says.
To fly straight to Jupiter, Juice would need 60,000 kilograms of fuel, an unacceptable load. It would also need more fuel to slow down so it could enter orbit around the planet. That means the scenic route, using the inner planets to get a gravitational boost to reach its destination, is the only way to get to the outer solar system, scientists say.
That approach will also be taken by NASA later this year when it launches its own moon mission, Europa Clipper, to Jupiter. The probe's trajectory will take it past Mars before returning to Earth for a second flyby to increase its speed. Despite launching more than a year after Juice, it will reach Jupiter in 2030 and focus on Europa, while its Europa counterpart will make Ganymede its primary target.
“We know that Europa has an ocean beneath its ice, and we’re pretty sure Ganymede has one too,” said Professor Emma Bunce, director of the University of Leicester’s Space Institute. “That makes them incredibly interesting targets for us to look at.”
Juice and Europa Clipper are set to make important contributions to the search for life in our solar system, which means a lot depends on how well ESA and NASA spacecraft engineers can handle their flybys – starting with Juice’s manoeuvres this week.
“It will be very exciting and a little scary,” added Professor Bunce. “However, this maneuver will be vital to the mission.” The more accurately this is accomplished, the less fuel we will need to correct course in the future, and the more opportunities we will have to explore Jupiter and its moons.”
Bunce, who was closely involved in the creation of two of Juice's instruments, added that the probe was not designed to directly detect life on Jupiter's moons: «It will settle the habitability question by studying the properties of the subsurface oceans. That will tell us whether life could exist there. Actually detecting life will be much harder.»
The idea that we might find alien life on the icy moons of planets in deep space would have seemed outlandish a few decades ago. The planets closer to the sun, particularly Venus and Mars, were thought to offer the best hope.
But Venus's surface temperature has been found to be 475 degrees Celsius, while its atmosphere is so hot that robotic probes landing there turn to dust. It has also been discovered that billions of years ago, Mars lost its atmosphere and surface water. Attempts to find signs of life beneath the surface have so far yielded no results, The Observer reminds.
In contrast, probes launched decades ago have shown that Jupiter's three main moons — Ganymede, Callisto and Europa — are icy worlds covered in vast oceans of liquid water, the only condition for life on Earth. «If there was ever a better place to look for life, it's here,» says American astronomer Neil deGrasse Tyson.
The problem is that they are very difficult to get to. A flight to Mars takes about eight months. Juice, which launched from ESA's Kourou spaceport in French Guiana last year, will take eight years to reach its destination, thanks to all the planetary flights it will need to get there starting this week.