Emergence Of Habitable Worlds Around Gas Giants Theme of Jupiter Mission

With input from scientists around the world, American and European scientists working on the potential next new mission to the Jupiter system have articulated their joint vision for the Europa Jupiter System Mission. The mission is a proposed partnership between NASA and the European Space Agency. The scientists on the joint NASA-ESA definition team agreed that the overarching science theme for the Europa Jupiter System Mission will be "the emergence of habitable worlds around gas giants."

This artist’s concept shows NASA's Jupiter Europa Orbiter which will carry a complement of 11 instruments to explore Europa and the Jupiter System. The spacecraft is part of the joint NASA-ESA Europa Jupiter System Mission (EJSM). Image credit: NASA/ESA

The proposed Europa Jupiter System Mission would provide orbiters around two of Jupiter's moons: a NASA orbiter around Europa called the Jupiter Europa Orbiter, and an ESA orbiter around Ganymede called the Jupiter Ganymede Orbiter.

Credit: NASA/ESA

"We've reached hands across the Atlantic to define a mission to Jupiter's water worlds," said Bob Pappalardo, the pre-project scientist for the proposed Jupiter Europa Orbiter, who is based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "The Europa Jupiter System Mission will create a leap in scientific knowledge about the moons of Jupiter and their potential to harbor life."

The new reports integrate goals that were being separately developed by NASA and ESA working groups into one unified strategy.

The ESA report is being presented to the European public and science community this week, and the NASA report was published online in December. The NASA report is available at http://www.lpi.usra.edu/opag .

The proposed mission singles out the icy moons Europa and Ganymede as special worlds that can lead to a broader understanding of the Jovian system and of the possibility of life in our solar system and beyond. They are natural laboratories for analyzing the nature, evolution and potential habitability of icy worlds, because they are believed to present two different kinds of sub-surface oceans.

The Jupiter Europa Orbiter would characterize the relatively thin ice shell above Europa's ocean, the extent of that ocean, the materials composing its internal layers, and the way surface features such as ridges and "freckles" formed. It will also identify candidate sites for potential future landers. Instruments that might be on board could include a laser altimeter, an ice-penetrating radar, spectrometers that can obtain data in visible, infrared and ultraviolet radiation, and cameras with narrow- and wide-angle capabilities. The actual instruments to fly would be selected through a NASA competitive call for proposals.

Ganymede is thought to have a thicker ice shell, with its interior ocean sandwiched between ice above and below. ESA's Jupiter Ganymede Orbiter would investigate this different kind of internal structure. The Jupiter Ganymede Orbiter would also study the intrinsic magnetic field that makes Ganymede unique among all the solar system's known moons. This orbiter, whose instruments would also be chosen through a competitive process, could include a laser altimeter, spectrometers and cameras, plus additional fields-and-particles instruments

The two orbiters would also study other large Jovian moons, Io and Callisto, with an eye towards exploring the Jupiter system as an archetype for other gas giant planets.

NASA and ESA officials gave the Europa Jupiter System Mission proposal priority status for continued study in 2009, agreeing that it was the most technically feasible of the outer solar system flagship missions under consideration.

Over the next few months, NASA officials will be analyzing the joint strategy and awaiting the outcome of the next Planetary Science Decadal Survey by the National Research Council of the U.S. National Academies. That survey will serve as a roadmap for new NASA planetary missions for the decade beginning 2013.

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.

Credit: NASA/ESA

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. 

Credit: NASA/ESA

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.

Credit: NASA/ESA

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.

 

Credit: NASA/ESA

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.

Jupiter Europa Orbiter (JEO)	Jupiter Ganymede Orbiter (JGO)

Sample Schedule

Sample JEO-JGO Timeline

Contacts and sources:
Jia-Rui Cook
Jet Propulsion Laboratory, Pasadena, Calif.

For more information about the Europa Jupiter System Mission, go to http://opfm.jpl.nasa.gov/europajupitersystemmissionejsm/ .

JPL is managed for NASA by the California Institute of Technology in Pasadena.