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The hunt for life on a
Jupiter moon
The possibility of an ocean beneath a layer of ice on the Jovian moon, Europa, strikes me as
exciting. Are there any planned NASA missions to Europa to search for life?
"Yes, The Europa Orbiter, which is a mission to map the ocean under the ice on Europa, will be
launched in the 2006 to 2007 time frame," says Dr. Edward J. Weiler, Associate Administrator of
NASA Space Science-- answering your question.
 The hunt for life on Europa is even more
intriguing than Mars. Images of Europa's frozen
crust taken in 1996 and 1997 hint that a liquid
ocean lies underneath. Europa may shelter
actual, not fossil life. Near volcanic vents
beneath Europa's conjectured sea, living
organisms may thrive on upwelling chemical
nutrients from the moon's interior as they do on
planet Earth.
Jupiter and its moons spinning above Europa
each day pull Europa from many directions.
Imagine Earth covered with a sheet of ice and its
oceans, trapped below, rising and falling as the
Moon orbits above. Similar but far greater tidal
forces act on Europa's icy crust. Heat from tidal
forces may have melted Europa's ice below the
surface. The melted ice may have formed trapped liquid oceans that stay liquid as they rise and
fall with the tides.
In 2007, we launch the Europa Orbiter spacecraft to find answers to our speculations. Arriving
at Jupiter's system in 2010, the spacecraft enters an orbit 200-kilometers above Europa a couple
of years later. It has a month to map the ocean before massive radiation (2 million rads) disables
it.
 During that month, a radar sounder bounces very-high
frequency radio waves through the ice to detect a liquid
surface below, which may be as little as 1 kilometer down
(about half as deep as the Grand Canyon). These
measurements answer the question of whether or not an
ocean exists.
An imaging device photographs and maps Europa's
surface with a resolution of 100 meters, showing features
smaller than a football field. A laser altimeter measures
the height of surface features (for example, huge ice
blocks) and gauges how much the surface rises and falls
with tidal tugs.
The 2007 mission is a precursor to a later mission that investigates Europa for life. Later we send
hydrobots (remote controlled submarines) to melt through Europa's ice crust and explore the
undersea realm. What life will we discover?
Figure Captions:
Figure 1. In 2013, the Europa Orbiter spacecraft in orbit above Jupiter's fourth largest moon will
determine whether a liquid sea exists below its ice crust. (Artist conception, courtesy of
JPL/NASA.)
Figure 2. A hydrobot (remote controlled submarine) exploring Europa's the undersea realm in a
later mission. (Artist conception of a future mission, courtesy of NASA.)
Further Surfing:
Europa Orbiter Mission, Mission at a glance, Europa Orbiter fact sheet, good links to other sites.
Detailed Images from Europa point to slush below the surface, Brown University news bureau
USATODAY.com Understanding Astronomy, Space.
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