Starstruck

NASA Eyes Mission to Jupiter's Ice Ocean Moon

The king of planets swings into view, as destination mission starts.
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NASA is proposing a mission to investigate life on Jupiter's ice-encrusted moon Europa.


Jupiter's mysterious moon Europa, famed for its role in 2001: A Space Odyssey, may soon host an intense search for life.

The White House this week presented a 2016 U.S. budget that includes $30 million in funding for the development of an ambitious mission to explore Europa. The ice-covered moon has long been suspected of harboring a hidden, saltwater ocean that could be habitable.

Alongside the tantalizing possibility of life under Europa's ice, the fact that the second of Jupiter's satellites is similar in size to Earth's moon, has more water than our own planet, and shows signs of organic chemistry makes it one of the most exciting destinations in the entire solar system. (See "The Hunt for Life Beyond Earth," in National Geographic magazine.)

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An illustration of the surface of Europa shows compounds from its hidden ocean bubbling up to the surface and spewing into space.


Ice Moon Ahoy

For the past 15 years NASA has been working on a design for a mission called the Europa Clipper. Launched sometime in the mid-2020s, it would travel in long, looping orbits around Jupiter and make at least 45 close flybys of Europa on a two-year mission.

Mission planners are considering including ground-penetrating radar that can look through the icy crust, high-resolution cameras that can map its craggy surface, and spectrometers that can sniff out Europa's trace atmosphere.

One fascinating surface feature NASA's mission will most likely target will be the bizarre reddish vein-like cracks that blanket the moon. The Hubble Space Telescope recently discovered geysers of water vapor erupting around Europa's south pole near these cracks. Speculation abounds that the vents may bring organic compounds up to the surface from the hidden ocean below. So NASA may fly the spacecraft straight through the suspected plumes, which may spout more than a hundred miles (161 kilometers) into space. That would allow NASA's instruments to taste and smell the blasts.

But the Clipper mission won't be alone, since the European Space Agency is also planning a run at Europa with its own mission, the Jupiter Icy Moons Explorer (JUICE), scheduled for launch in 2022. The goal will be to investigate not only Europa but also its neighboring ice-covered moons, Callisto and Ganymede.

Depending on what the Europa Clipper and JUICE missions stumble upon, an even more exciting lander mission could move from drawing boards and science wish lists to reality.

NASA is working already on demonstrating technologies that would allow spacecraft to land and then drill into the many miles of Europa's thick ice sheet and release a robotic submersible into the ocean below. At that point, we may learn whether a large body of salty water lies hidden under all that ice and if there is life lurking in the darkness.

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This skychart shows Jupiter rising in the early evening in the eastern sky. The insert shows the telescope view of Jupiter and its moons as they appear on February 6, 2015.


See for Yourself

For sky-watchers, Jupiter is now at its biggest and brightest in the night sky this year, making it a supereasy target to hunt down.

That's because the giant planet is officially at opposition, aligned with Earth in its separation from the sun and consequently dominating the nighttime sky, rising in the east just after sundown. The planet will appear to rise high in the southern sky after midnight and then slowly settle down in the west by dawn.

While to the naked eye Jupiter, 404 million miles (650 million kilometers) away, looks like a brilliant yellow star, a pair of steadily held binoculars will reveal its four Galilean moons. They will appear lined up like a row of ducks beside the planetary disk.

Using the sky chart above, Europa can easily be identified. Keep tabs on all four moons over the course of hours and days, and you will notice that they change positions as they orbit their host planet.

A small telescope, however, will reveal even more of the giant planet's beauty. At high magnification, Jupiter's brown cloud belts become visible, and with patience even the Great Red Spot comes into focus.

It's amazing to ponder that this tiny feature, oval and pink, is a monster hurricane—large enough to swallow three Earth-size planets—that has been raging for at least a couple of centuries across the face of Jupiter.

Happy hunting!

Follow Andrew Fazekas, the Night Sky Guy, on Twitter, Facebook, and his website.

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