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Wall of gas divides
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C1XS takes first taste of lunar X-rays

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Video archive

STS-120 day 2 highlights

Flight Day 2 of Discovery's mission focused on heat shield inspections. This movie shows the day's highlights.


STS-120 day 1 highlights

The highlights from shuttle Discovery's launch day are packaged into this movie.


STS-118: Highlights

The STS-118 crew, including Barbara Morgan, narrates its mission highlights film and answers questions in this post-flight presentation.

 Full presentation
 Mission film

STS-120: Rollout to pad

Space shuttle Discovery rolls out of the Vehicle Assembly Building and travels to launch pad 39A for its STS-120 mission.


Dawn leaves Earth

NASA's Dawn space probe launches aboard a Delta 2-Heavy rocket from Cape Canaveral to explore two worlds in the asteroid belt.

 Full coverage

Dawn: Launch preview

These briefings preview the launch and science objectives of NASA's Dawn asteroid orbiter.

 Launch | Science

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More video

Jupiter mission given

poll position


Posted: 19 February, 2009

NASA and ESA officials have decided to first go ahead with an ambitious mission to Jupiter and Europa, following up with another mission to visit Saturn’s moons Titan and Enceladus.

Both missions are destined to set the stage for the future of planetary science research and have been labelled as outer-planet flagship missions that could eventually answer questions about how our Solar System formed and whether habitable conditions exist elsewhere in the Solar System.

NASA and ESA will venture forth to the Jupiter system together. Image: NASA/ESA.

The missions are derived from the merger of separate NASA and ESA mission concepts. Proposals to NASA included a Europa orbiter and a Titan orbiter to revisit Saturn's moon. ESA’s missions, falling under the Cosmic Visions programme, were called Laplace and Tandem, again, two missions to explore Europa and Titan respectively. Laplace included a proposal to land on the surface of Europa, and Tandem would explore both Titan and Enceladus.

After studying the feasibility of both types of mission, NASA and ESA scientists and engineers concluded that the Europa mission would be given the poll position, but that the scientific merits of both missions could not be separated, so both missions should move forward for further study and implementation.

"The decision means a win, win situation for all parties involved," says 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 several more steps and detailed studies before officially moving forward. "This joint endeavour is a wonderful new exploration challenge and
will be a landmark of 21st Century planetary science," says 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."

Artist's impression of a possible future ESA/NASA mission to Saturn's system that would explore Titan and Enceladus. Image: NASA/ESA.

Both missions present new exploration challenges. The Europa Jupiter System Mission will use two robotic orbiters to
conduct unprecedented detailed studies of Jupiter and the Galilean Satellites: Io, Europa, Ganymede and Callisto. NASA and ESA will share the workload; NASA will take on the Jupiter Europa Orbiter and ESA will build another spacecraft, initially named Jupiter Ganymede Orbiter. The mission proposal will see the two spacecraft launch in 2020 on two separate launch vehicles from different launch sites. They will reach the Jupiter system in 2026 and spend at least three years exploring the worlds.

The Galilean Satellites provide a unique example of how four moons orbiting the same body can vary so greatly. Io, the innermost moon, is the most actively volcanic body in the Solar System. Europa is suspected to harbour an ocean under its icy shell, and Ganymede is also thought to have a deep underwater ocean, and is the only moon known to have its own internally-generated magnetic field. Callisto’s surface is heavily cratered and ancient, providing a record of events from the early history of the Solar System. All four moons would provide a unique insight into the evolution of the Jovian system.

The Titan Saturn System Mission would consist of a NASA orbiter and an ESA lander and research balloon, which will continue to be developed as NASA and ESA define their planetary exploration roadmaps for the next decades.