EJSM/Laplace

Europa Jupiter System Mission – Laplace

Artist concept of the Europa Jupiter System Mission: Jupiter Europa Orbiter (top) and Jupiter Ganymede Orbiter (bottom)
Operator	Proposed joint ESA/NASA
Mission type	Multiple orbiters and lander
Homepage	Europa Jupiter System Mission

The Europa Jupiter System Mission – Laplace (EJSM/Laplace) was a proposed joint NASA/ESA unmanned space mission slated to launch around 2020 for the in-depth exploration of Jupiter's moons with a focus on Europa, Ganymede and Jupiter's magnetosphere. The mission would comprise at least two independent elements, NASA's Jupiter Europa Orbiter (JEO) and ESA's Jupiter Ganymede Orbiter (JGO), to perform coordinated studies of the Jovian system.

The Japan Aerospace Exploration Agency (JAXA) and the Russian Federal Space Agency (Roscosmos) had expressed their interest in contributing to EJSM, although no deals had been finalized. JEO was estimated to cost $4.7 billion, while ESA would spend $1.0 billion (€710 million) on JGO.

In April 2011, ESA stated that it seemed unlikely that a joint US–European mission will happen in the early 2020s given NASA's budget, so ESA is investigating the possibility of proceeding with a European-led mission. The ESA-led mission is called the Jupiter Icy Moon Explorer (JUICE) and will be based on the JGO design. Selection of JUICE for the L1 launch slot of ESA's Cosmic Vision science programme was announced on May 2, 2012.

Origins

In February 2008, NASA and ESA began joint investigations into sending a probe to study the icy satellites of the outer solar system under the title Outer Planet Flagship Mission. Two primary candidate missions were considered under the study: EJSM and Titan Saturn System Mission (TSSM), also known under the ESA designation TandEM.

In February 2009 it was announced that NASA/ESA had given EJSM priority ahead of the TSSM. The ESA contribution still faced funding competition from two other missions, the Laser Interferometer Space Antenna (LISA) and the International X-ray Observatory (IXO), which is why NASA kept a contingency plan of sending its part of the mission as a stand-alone project.

On 18 February 2009 NASA and ESA jointly announced that both missions could proceed forward, but the EJSM would be the first, departing Earth in 2020 and arriving at Jupiter in 2026. The Titan mission would be launched at a later date.

Following NASA's 2011 decadal survey and budget, a joint mission is unlikely to happen in the proposed timeframe, so ESA is investigating the possibility of proceeding with a European-led mission.

Mission architecture

A map showing all the nations which are either currently part of (red) or interested in becoming a part of (brown) the EJSM

The most distinctive feature of the EJSM/Laplace-study, are its proposed two, possibly three, or even four separate orbiters/landers.

• NASA: Jupiter Europa Orbiter (JEO), planned to study Europa and Io.
• ESA: Jupiter Ganymede Orbiter (JGO), planned to study Ganymede and Callisto
• JAXA: Jupiter Magnetospheric Orbiter (JMO), planned to study Jupiter's magnetosphere.
• Roscosmos: Europa Lander, planned to land on Europa's surface for in situ studies.

The baseline EJSM architecture consists of JEO and JGO, which are proposed to be launched in 2020 and will execute an intricately choreographed exploration of the Jupiter System before settling into orbit around Europa and Ganymede, respectively. The JEO and JGO are separate and independent spacecraft developed, launched and operated by their respective organizations to work together. Their launch dates and interplanetary trajectories are not dependent on each other. 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.

Both satellites are 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 confirm the hypothesized water oceans beneath the ice shells of Europa and Ganymede. Should Japan (JAXA) join the project, JMO will explore the Jovian magnetosphere in situ as a template for an astrophysical magnetised disk and affording the opportunity for "3-point" investigations of the Jupiter system via synergistic observations with JGO and JEO.

Objective

The objective is to determine whether the Jupiter system harbors habitable environments. 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.

Possible addition of a Russian Europa lander

The Russian Federal Space Agency (Roscosmos) and the Russian Academy of Sciences are considering an independent Russian segment of the mission with the objective of delivering a lander to Europa, called Europa Lander. It would be separately launched by a Soyuz-class launcher relying on the ESA and/or NASA-orbiters to relay its data to Earth. A broad international involvement in the science payload and exploration tools of the descent module is envisaged. Depending on the available resources, a combination of a grinder on a robotic arm, or even a drill/thermal penetration system is envisaged in order to determine the characteristics of Europa's surface ice. Other landing scenarios suggest the use of high-velocity impactors which penetrate through the irradiated surface material to reach pristine ice. Once impacted, the probe can release a melting system to explore the shallow subsurface of Europa.

External links

• Joint NASA/ESA report on the Laplace/EJSM mission
  • Detailed report on the ESA contribution to the Europa Jupiter System Mission
  • Detailed report on the NASA contribution to the Europa Jupiter System Mission
• Benson – Solar Power for Outer Planets Study (2007) – NASA (with analysis of using solar power at Jupiter)