February 18, 2009

NASA, ESA Join Forces On Jupiter Moon Missions

Officials with NASA and the European Space Agency (ESA) met in Washington last week, deciding to pursue an ambitious plan to send a probe on a mission to Jupiter and Europa, the planet's icy moon.  A mission to visit Titan and Enceladus is also being considered.

These bold, outer-planet missions could ultimately answer critical questions about the formation of the solar system, and help scientists determine whether habitable conditions exist elsewhere in the solar system.

The Europa Jupiter System Mission and the Titan Saturn System Mission are the result of the combination of separate NASA and ESA mission concepts. 

In 2007, NASA originally studied four mission concepts that were later narrowed down to two proposals in 2008 -- one to send an orbiter to Europa to study the icy moon and its subsurface water ocean, and another to send a Titan orbiter to revisit Saturn's moon.  

At the same time, ESA had also initiated a competition to select their flagship mission for the Cosmic Vision 2015-2025 slot of its scientific program.  The agency narrowed the field two finalists, called Laplace and Tandem, for further study. Laplace would send a spacecraft to orbit Jupiter and eventually orbit and possibly land on Europa.  Tandem involved sending a spacecraft to orbit Titan and explore its surface, after exploring the surface of Enceladus, another moon of Saturn.

Scientists and engineers with NASA and ESA carefully studied these missions ahead of last week's meeting in Washington. Based on studies and rigorous independent assessment reviews, NASA's Europa Jupiter System Mission, called Laplace in Europe, was considered more technically feasible to implement initially. 

However, ESA's Solar System Working Group found that the scientific merits of both missions could not be separated. They argued that both missions should move forward for further study and implementation.  NASA agreed with the conclusion.
"The decision means a win, win situation for all parties involved," said Ed Weiler, associate administrator for NASA's Science Mission Directorate in Washington.

"Although the Jupiter system mission has been chosen to proceed to an earlier flight opportunity, a Saturn system mission clearly remains a high priority for the science community."

Both agencies will need to undertake detailed studies and several additional steps before moving forward.

"This joint endeavor is a wonderful new exploration challenge and will be a landmark of 21st Century planetary science," said David Southwood, ESA Director of Science and Robotic Exploration.

"What I am especially sure of is that the cooperation across the Atlantic that we have had so far and we see in the future, between America and Europe, NASA and ESA, and in our respective science communities is absolutely right. Let's get to work," he said.
The Europa Jupiter System Mission will use two robotic orbiters to conduct unprecedented studies of the enormous gaseous planet Jupiter and its moons Io, Europa, Ganymede and Callisto. NASA will build one spacecraft, initially named Jupiter Europa Orbiter, while the ESA will build the other, initially named Jupiter Ganymede Orbiter. The two spacecraft, which will launch on two separate launch vehicles from different launch sites, are scheduled to launch in 2020 and reach the Jupiter system in 2026, where they will spend at least three years conducting research.

Europa, which is believed to have an ocean, is a unique target to study habitability around Jupiter.  Ganymede, the solar system's largest moon, is the only moon known to have its own internally-generated magnetic field, something scientists have long sought to understand.  It is also believed to have a deep undersurface water ocean. The two orbiters will spend about a year orbiting Europa and Ganymede, respectively.

Io, the solar system's most volcanically active body, and heavily cratered Callisto may provide a record of events from the early history of the solar system, are also critical targets of the Jupiter System Mission.

The Titan Saturn System Mission under consideration would use a NASA orbiter and an ESA lander and research balloon. The sophisticated mission presents several technical challenges that require significant study and technological development.

The National Academy in Washington is working on establishing a roadmap for new NASA planetary missions to begin after 2013.  In Europe, interested scientists must re-submit the Titan mission at the next opportunity for mission proposals in the Cosmic Vision program.

ESA's Directorate of Science and Robotic Exploration will manage the European contribution to the Jupiter mission, while NASA's Jet Propulsion Laboratory in Pasadena, California, will manage NASA's contributions to the projects for NASA's Science Mission Directorate in Washington.


Image 1: In February 2009, ESA and NASA selected their future flagship mission to the outer Solar System - a new project to explore Jupiter and its four largest moons. Credits: NASA/ESA

Image 2: Artist's impression of a possible future ESA/NASA mission to Saturn's system. The mission, called Tandem in Europe, is a set of spacecraft to orbit Titan, explore its surface, after exploring the surface of another moon of Saturn, Enceladus. Credits: NASA/ESA


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