As the latest exploration of Mars is in full swing, a new wave of missions targeting Jupiter is also underway. The European Space Agency’s “Jupiter Icy Moons Explorer” was the first to launch last year, heading to Jupiter, followed by NASA’s “Europa Clipper,” which embarked on October 15 to explore the potential for life on Jupiter’s moon, Europa. Why has Jupiter recently drawn so much attention from the global space community, and what challenges make exploring Jupiter so difficult?
Distance Is the Primary Challenge
In its analysis of NASA’s “Europa Clipper” mission, the U.S. website “Space” highlighted that the vast distance is the top obstacle to exploring Jupiter. While Earth, Mars, and Jupiter are the third, fourth, and fifth planets from the Sun, respectively, their distances are not evenly distributed. Astronomers use the average distance from Earth to the Sun, known as one astronomical unit (AU), for comparison. Mars is 1.52 AU from the Sun, while Jupiter is a much farther 5.2 AU away. Therefore, any probe heading to Jupiter must first overcome this immense interstellar distance.
CNN noted that the “Europa Clipper” is the largest planetary probe NASA has ever built, weighing approximately 6 tons, including 3.24 tons of equipment and 2.75 tons of fuel. To maximize its speed, NASA chose the Falcon Heavy rocket, the second most powerful rocket in operation, second only to NASA’s Space Launch System (SLS), which is designed for the Artemis moon missions. The Falcon Heavy was used without its typical recovery mode, with the support frame removed and fuel fully used to achieve maximum acceleration. Even with these measures, the “Europa Clipper” still lacks sufficient power for its journey. Therefore, NASA designed a complex flight path, requiring the probe to accelerate twice using gravity assists from Mars and Earth over five and a half years to cover 2.9 billion kilometers, entering Jupiter’s orbit around 2030.
In contrast, the European Space Agency’s “Jupiter Icy Moons Explorer” launched earlier, on April 14, 2023, but lacks the initial velocity provided by a large rocket like the Falcon Heavy. As a result, it must follow an even more complex trajectory. If it were to fly directly to Jupiter, it would require more than 60,000 kg of fuel, with additional fuel needed for deceleration and orbit entry, far exceeding the probe’s total weight. Thus, it will use gravity assists from Earth, the Moon, and Venus four times to adjust its speed and direction. In August 2023, the European Space Agency reported that the “Jupiter Icy Moons Explorer” had successfully completed a flyby of Earth and the Moon, using their gravity to take a “shortcut” through Venus toward Jupiter. It is expected to reach Jupiter’s orbit in 2031, slightly later than the “Europa Clipper.”
The Challenges of Exploring Jupiter
As the largest planet in the solar system in both size and mass, Jupiter is full of mysteries. Its average diameter is 140,000 kilometers, 11 times that of Earth, and its mass is greater than all the other planets in the solar system combined. It is also the fastest-rotating planet, with a rotation period of just 9 hours, 55 minutes, and 30 seconds. These unique features have drawn numerous probes to Jupiter, including Pioneer 10 and 11, Voyager 1 and 2, Ulysses, Galileo, Cassini, and New Horizons.
However, Jupiter’s peculiarities also present unprecedented challenges for these missions. For example, Jupiter has the strongest magnetic field of any planet in the solar system, 14 times stronger than Earth’s. The interaction between Jupiter’s magnetic field and the solar wind creates intense radiation belts extending millions of kilometers, with radiation levels high enough to be lethal to astronauts. NASA’s Galileo probe encountered over 20 malfunctions due to insufficient preparation for these conditions. Later missions reinforced their radiation protection, but it remains difficult to conduct long-term scientific activities near Jupiter.
Additionally, due to Jupiter’s great distance from the Sun, the available solar energy is only 1/25th of what is available near Earth. Large solar panels are essential for powering the probes. For instance, the “Europa Clipper” is equipped with a pair of solar panels that span 30.5 meters when fully deployed, wider than a standard basketball court, making them the largest solar panels ever developed by NASA for planetary missions. Furthermore, when the probe is in Jupiter’s shadow, temperatures can drop to -240°C, so the equipment must be able to operate in such extreme cold.
What Is the Attraction of Jupiter?
According to the “Space” website, one of the main reasons Jupiter has garnered so much attention in recent years is its moons. Jupiter, often described as a “mini solar system” due to its many moons, possesses all the elements of such a system. Previous exploration has shown that Europa and Ganymede, two of Jupiter’s moons, are covered by thick ice layers, and oceans may exist beneath the ice. These moons, known as icy moons, are the target of the European Space Agency’s “Jupiter Icy Moons Explorer.” Equipped with optical cameras, spectrometers, and magnetometers, it will study the ice shells and chemical composition of the moons, as well as Jupiter’s atmosphere and magnetic field. Scientists believe Europa and Ganymede could harbor life, though Europa’s orbit is fully within Jupiter’s radiation belt, exposing it to intense radiation. As a result, the “Jupiter Icy Moons Explorer” will spend less time studying Europa and focus primarily on Ganymede, the largest moon in the solar system and the only known moon with a magnetic field.
The “Europa Clipper,” on the other hand, will concentrate its efforts on Europa. Scientists have discovered that Europa’s water volume may be twice that of Earth’s oceans, and tidal heating caused by the gravitational interaction with Jupiter’s other moons, Io and Ganymede, may keep its subsurface ocean in a liquid state, potentially supporting life. The “Europa Clipper” will not orbit Europa but will conduct nearly 50 flybys while orbiting Jupiter, gradually building a global scan of the moon. Instruments aboard the probe will measure the depth and salinity of Europa’s ocean, analyze materials ejected from the moon, use radar to penetrate the ice shell, and scan for organic molecules and thermal activity. NASA has made it clear that the mission’s core objective is to determine whether Europa’s ocean could support life.
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