Set to launch Thursday (April 13), the Jupiter Ice Explorer (JUICE) is on an eight-year journey to Jupiter, with the spacecraft expected to reach the gas giant in July 2031.
The European Space Agency (ESA) spacecraft will monitor Jupiter And three of its large moons that surround the ocean – Ganymede, Callisto and Europa Describe the Jovian system in great detail.
Jupiter rotates, in the middle (Opens in a new tab)And It’s about 444 million miles (715 million kilometers) from Earth, so it’s clearly more than a hop, skip and jump to the giant planet. But other missions have made the trip from Earth to Jupiter much faster than that juice will.
Related: Facts about the JUICE Jupiter mission in Europe
As it turns out, one of the main factors dictating travel time to Jupiter is whether the spacecraft will fly by the gas giant or enter orbit on a relatively long-duration mission.
The first spacecraft to travel from Earth to Jupiter was NASA Pioneer 10, which was launched on March 3, 1972, and flew over Jupiter on December 3, 1973, which means that it reached the gas giant in just 640 days. Pioneer 11 was the fastest in the flyby, reaching Jupiter in just 606 days.
Then there are the orbiters, which should be more thought out than the hovercraft because they have to travel slowly enough at the end of the trip to be caught by Jupiter’s gravity. JUICE will travel for eight years through deep space. NASA agency Galileo The probe took about six years to make the trip to Jupiter, launching in October 1989 and reaching orbit in December 1995. Agency Agency Juno The spacecraft was launched in August 2011 and reached its destination in July 2016.
These differences in Jupiter’s orbital travel times stem from several factors. For example, the distance between Land And Jupiter varies greatly over time. In addition, orbiter missions do not take direct paths to the giant planet; They travel a scenic route around the inner solar system, fly over other planets to boost speed, and carve a “gravity assisted” path.
For example, Galileo traveled about 2.5 billion miles (4 billion kilometers) to reach the gas giant, taking gravitational aids from Venus, Earth, and even the asteroid Gaspra along the way. JUICE will use a similar strategy.
“It will perform a complex sequence of gravity-assisted maneuvers, starting one year after launch, taking in the gravitational aids of the Moon and Earth, and both objects at the same time for additional energy,” ESA scientist Alessandro Atzi said during a JUICE news conference about the mission. April 6 “Then we have gravity assist on Venus [and] Earth’s gravity helped them in 2026 and 2029 reach Jupiter in July 2031.”
Related: How does gravity help work?
What is gravity assist?
Gravity helps It is an aviation technology that can enhance the momentum of spacecraft. Mission planners use gravity assists to send spacecraft on journeys that would not be possible through a direct trajectory; It will require a lot of fuel, for example.
Gravity assist can also be used to “steal” momentum from a spacecraft. The Galileo mission is a case in point; NASA spacecraft lowered its energy relative to Jupiter by flying in front of the volcano Jovian Moon Ayo. Thrust is used to speed up and slow down spacecraft, so assisting gravity to steal energy can reduce the amount of fuel a spacecraft needs to get itself into orbit.
Gravity assist works in a similar way to a ball rolling down a hill into a valley, by switching between gravitational potential energy and kinetic energy, Planetary Society explains (Opens in a new tab). When a spacecraft approaches a planet, it falls into the celestial body’s gravity and gains kinetic energy, and accelerates while losing gravitational potential energy. The spacecraft then leaves the planet on a new trajectory, which can be modified by changing the distance the spacecraft passes the planet. So planetary flybys can have a “slingshot effect” on a spacecraft, helping it make the most of its limited fuel supply.
JUICE is one such spacecraft.
“We simply don’t have enough energy [at launch] to go into a more direct orbit [around Jupiter]So we need to do all these gravitational maneuvers in order to gradually increase the spacecraft’s power to get to Jupiter.”
The extra energy given to the spacecraft must come from somewhere – the motion of the planet. However, the difference in mass between a spacecraft and a planet is so great, that the resulting deceleration on the planet is too small to actually measure.
For example, file Planetary Society says that when NASA’s Voyager 1 made its gravity-assisted flyby of Jupiter in 1979, the gas giant slowed in its orbit by about 0.0000000000000000000000010 kilometers per second while Voyager 1 I got a speed boost of 10 kilometers per second.
The inner planets lend a hand: the gravity of the juice helps
To reach Jupiter, JUICE will receive a total of four gravitational aids to the inner solar system, from the moonEarth and Venus. (In 2017, the European Space Agency was proposing a fifth and final gravitational aid from Mars about three years before reaching Jupiter, but that is no longer in the plan.)
JUICE will head for its first gravity assist in August 2024 after completing its first solar orbit, and this will be very special for the ESA spacecraft and for space exploration in general. This would be a joint lunar-Earth gravity assist, officially called Lunar-Earth Gravity Assist (LEGA), the first time such an operation has been performed.
“The first one is going to be very difficult, because it won’t just be terrestrial gravitational assistance – gravitational assistance of the Moon and the Earth, which means we have to go through the Earth and the Moon at the same time,” Atzi added. “So this will be the most accurate gravity-assisted maneuver ever performed.”
JUICE’s next gravity assist will happen a year later, in August 2025, when the spacecraft will get a boost from the second planet from the Sun, Venus.
Both of the spacecraft’s next two gravitational aids will come from Earth. JUICE will fly by our planet in September 2026, then make one last visit to Earth in January 2029, when it will receive another gravitational “kick”, the last time before it reaches Jupiter.
However, that wouldn’t be the end of the cuteness helping JUICE. Even after it begins its science mission, the spacecraft will need to perform gravity assists to reach the moons Ganymede, Europa, and Callisto. (JUICE will orbit Jupiter at first, and make several flybys of these three moons. Then it will go into orbit Ganymede In 2035, becoming the first probe to orbit a moon other than Earth.)
“The gravity aids have to be precise, but we have very competent personnel in mission control, and they are used to these maneuvers,” Atzi added.
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