Overview

NASA is targeting a launch in October 2024 for the Europa Clipper spacecraft. It will launch from the agency’s Kennedy Space Center in Florida on a journey to the Jupiter system, where it will make multiple flybys of the ocean moon Europa. With gravity assists from Mars and Earth, the journey to Jupiter will take 5½ years. The spacecraft’s prime mission, which will also include flybys of the Jovian moons Ganymede and Callisto, will be a little over four years, from 2030 to 2034.

Europa Clipper’s team had to carefully plan the spacecraft’s launch period because of celestial mechanics. The spacecraft needs to fly by Mars, then Earth, to gain velocity for its journey out to Jupiter, and the planets are constantly moving around the Sun. Mission designers had a limited set of choices for when Mars and Earth would be in the right places at the right times. The launch period also needed to account for a fixed date to arrive at Jupiter: April 11, 2030. (The mission required a set arrival date to plan out the complicated tour around Jupiter.)

SpaceX’s Falcon Heavy is a two-stage rocket with side boosters. Because Europa Clipper needs a lot of energy for its interplanetary trajectory to Jupiter, the rocket for this launch will be fully expendable, with the exception of a recoverable fairing (nose cone). This means that there will be no return of first-stage boosters for this launch, though Europa Clipper is reusing the side boosters from the 2023 launch of NASA’s Psyche mission to the asteroid Psyche.

Exact timelines will vary by launch date, but the Europa Clipper spacecraft will separate from the rocket a little over an hour after liftoff. The length of time between liftoff and separation grows slightly through the launch period from about one hour and one minute to about one hour and 10 minutes.

After separating from the rocket, Europa Clipper will look for the Sun, as well as prepare the propulsion system to start controlling its orientation in space. Around this same time, the spacecraft will also start attempting to communicate with its operations team on Earth. How soon mission controllers first acquire Europa Clipper’s signal will depend on when the spacecraft gets into an orientation that allows it to establish a direct connection with ground stations on Earth. The earliest the mission could acquire the spacecraft’s signal is about five minutes after separation, but it may take up to about 19 minutes. The first data is expected to indicate that the spacecraft is alive but may not include full engineering information (telemetry), which allows engineers to assess how the spacecraft is functioning. That data is expected about 19 minutes after separation.

Another critical activity that takes place early after separation is the deployment of Europa Clipper’s enormous solar arrays. If all goes as expected, the last latch holding the solar arrays folded against the spacecraft bus will be released at about two hours after the spacecraft separates from the rocket, and the arrays will take about 10 minutes to unfold.

During the cruise phase, Europa Clipper will travel to its destination in the Jupiter system and prepare for its activities there. This phase begins about a day after launch and lasts about five years and three months.

Europa Clipper will fly relatively close to Mars and Earth for two maneuvers known as gravity assists: The spacecraft will use the speed at which each planet travels around the Sun, harnessing the planet’s gravity to increase Europa Clipper’s own speed and change its direction. (This effect is similar to how a ball thrown at a moving train will bounce off the train in another direction at a higher speed.) Gravity assists help a spacecraft reach its destination faster for a given amount of propellant.

Depending on when Europa Clipper lifts off in its launch period, the Mars flyby will take place between Feb. 28 and March 4, 2025, with altitudes varying between about 304 and 646 miles (490 to 1,040 kilometers) above the surface. The Earth flyby will take place between Dec. 2 and 7, 2026, with altitudes varying from about 1,951 to 2,144 miles (about 3,140 to 3,450 kilometers) above the surface, depending on the actual launch date.

In addition, the mission team plans to shape the spacecraft’s orbit with trajectory correction maneuvers, which require firing thrusters to keep the spacecraft on the right path to Jupiter.

During cruise, the spacecraft team will also deploy the magnetometer boom and radar antennas, test instruments and subsystems, and make sure the spacecraft is ready to study the Jupiter system.

For all liftoff dates within the launch period, the spacecraft is scheduled to begin orbiting Jupiter on April 11, 2030. The arrival phase begins in January — three months before the engine burn that inserts the spacecraft into Jupiter orbit — and concludes a few hours after the maneuver.

Toward the end of the arrival phase, the spacecraft will perform a close flyby of the large Jovian moon Ganymede. The Ganymede flyby, which takes place about 12 hours before Jupiter orbit insertion, brings the spacecraft to within about 120 miles (200 kilometers) of Ganymede’s surface.

While the spacecraft will use Mars’ and Earth’s gravity to speed up on the way to Jupiter, the spacecraft will use Ganymede’s gravity to slow down. Ganymede’s gravity will pull the passing spacecraft back toward the moon, decreasing its velocity.

With the assist from Ganymede, the spacecraft can decrease the amount of time it needs to burn its engines to slow down enough to be captured by Jupiter’s gravity. (The burn in this case will be about six hours.) After this burn, Europa Clipper will start its first orbit around the solar system’s largest planet.

Europa Clipper’s tour of the Jupiter system begins April 11, 2030. The trajectory is designed to allow the spacecraft to observe as much of the moon Europa as possible while keeping the spacecraft as safe as possible from the hazardous radiation environment near the moon.

Capable of quickly damaging electronics, Jupiter’s radiation environment is the most intense of any planet in the solar system. Europa resides in one of the most powerful zones of radiation around Jupiter.

Previous Jupiter missions have spent less time in the hazardous radiation zones. NASA’s Galileo mission only flew a handful of times by Europa and Io, the moons in the most hazardous zones around Jupiter, during its primary mission from 1995 to 1997. Then, during its extended mission, which ended in 2003, Galileo did take on additional risk later in its tour of Jupiter by flying by Europa and Io several more times.

The radiation is also on average more dangerous in the plane around the planet’s equator. NASA’s Juno spacecraft, which arrived at Jupiter in 2016, generally orbits over the planet’s poles. Like Europa Clipper, Juno’s trajectory throughout its mission has also been designed to minimize time spent within Jupiter’s most powerful radiation belts.

Europa Clipper’s mission at Jupiter involves 49 flybys of Europa dedicated to scientific investigation, plus seven additional flybys of Ganymede and nine flybys of Callisto to help shape the spacecraft’s trajectory.

For more on what kinds of science data Europa Clipper will be gathering during its tour of the Jupiter system, see the Science section.

Because it is scientifically important to ensure that the Europa Clipper spacecraft does not come in contact with Europa’s surface and contaminate the moon with significant numbers of Earth microbes, NASA’s current plan to dispose of the spacecraft after its science mission ends is by impacting with Ganymede. Planetary contamination is not an issue with Ganymede because Ganymede’s surface is likely not active today and its ice shell is substantially thicker than Europa’s, minimizing contact between the spacecraft and any possible ocean underneath. The current plan for disposal begins 30 days after the last science-dedicated flyby of Europa. Mission designers have planned for several additional flybys of Europa to shape the spacecraft’s trajectory toward a final impact with Ganymede, which is currently expected in September 2034.