Europa Jupiter System Mission (EJSM)

A Joint International Mission
The baseline EJSM consists of two primary flight elements operating in the Jovian system: the NASA-led Jupiter Europa Orbiter (JEO), and the ESA-led Jupiter Ganymede Orbiter (JGO). JEO and JGO will execute a choreographed exploration of the Jupiter System before settling into orbit around Europa and Ganymede, respectively. JEO and JGO carry 11 and 10 complementary instruments, respectively, to monitor dynamic phenomena (such as Io’s volcanoes and Jupiter’s atmosphere), map the Jovian magnetosphere and its interactions with the Galilean satellites, and characterize water oceans beneath the ice shells of Europa and Ganymede.

Watch the EJSM Video





Science Theme

By understanding the Jupiter system and unraveling its history from origin to the possible emergence of habitable worlds, a better understanding will be gained as to how gas giant planets and their satellites form and evolve. Most important, new light will be shed on the potential for the emergence of life in the galactic neighborhood and beyond. Thus, the overarching theme for EJSM has been formulated as: The emergence of habitable worlds around gas giants. To understand the Galilean satellites as a system, Europa and Ganymede are singled out for detailed investigation. This pair of objects provides a natural laboratory for comparative analysis of the nature, evolution, and potential habitability of icy worlds. The primary focus is on an in-depth comparative analysis of their internal oceans, current and past environments, surface and near-surface compositions, and their geologic histories. Moreover, objectives for studying the other two Galilean satellites, Io and Callisto, are also defined. To understand how gas giant planets and their satellites evolve, broader studies of Jupiter’s atmosphere and magnetosphere will round out the Jupiter system investigation.

Goal: Determine Whether the Jupiter System Harbors Habitable Worlds. The fundamental theme for EJSM can be further focused into science objectives relating to habitability (focusing on Europa and Ganymede). The main science objectives supporting this goal are:

• Characterize sub-surface oceans
• Characterize the ice shells and any subsurface water
• Characterize the deep internal structure for Ganymede and the intrinsic magnetic field
• Compare the exospheres, plasma environments, and magnetospheric interactions.
• Determine global surface compositions and chemistry
• Understand the formation of surface features, including sites of recent or current activity, and identify and characterize candidate sites for future in situ exploration.

Goal: Characterize the Processes Within the Jupiter System. The Jupiter system includes a broad diversity of objects, including Jupiter itself, 55 currently known outer irregular satellites, the Jovian ring system, four small inner satellites, and the four large Galilean Satellites: Io, Europa, Ganymede, and Callisto. The main science objectives supporting this goal are:

• Understand the Jovian satellite system, especially as context for Europa and Ganymede.
• Evaluate the structure and dynamics of the Jovian atmosphere.
• Characterize processes the Jovian magnetodisk/magnetosphere.
• Determine the interactions occurring in the Jovian system.
• Constrain the origin of the Jupiter system.

One Mission, Two Flight Systems

The JEO and JGO are separate and independent spacecraft developed, launched and operated by their respective organizations to work together in the Jupiter system toward a common set of science goals and objectives. Their launch dates and interplanetary trajectories are not dependent on each other. They both rely on proven capable and robust design strategies; however, only JEO needs to operate in the inner radiation belts. While each flight system will focus on two of the four Galilean satellites, by operating together they allow full system coverage including Jupiter, its magnetosphere, and its rings.

Sample Schedule

Sample JEO-JGO Timeline