Space Briefs
What would we want
to know if we landed
on Jupiter’s Europa?
Most of what scientists know of Jupiter’s moon Europa they
have gleaned from a dozen or so close flybys from NASA’s
Voyager 2 spacecraft in 1979 and NASA’s Galileo spacecraft
in the mid-to-late 1990s. Even in these fleeting, paparazzi-like
encounters, scientists have seen a fractured, ice-covered world
with tantalizing signs of a liquid water ocean under its surface.
Such an environment could potentially be a hospitable home for
microbial life. But what if we got to land on Europa’s surface and
conduct something along the lines of a more in-depth interview?
What would scientists ask? A new study in the journal Astrobiology
authored by a NASA-appointed science definition team lays out
their consensus on the most important questions to address.
“If one day humans send a robotic lander to the surface of
Europa, we need to know what to look for and what tools it
should carry,” said Robert Pappalardo, the study’s lead author,
based at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.
“There is still a lot of preparation that is needed before we could
land on Europa, but studies like these will help us focus on the
technologies required to get us there, and on the data needed
to help us scout out possible landing locations. Europa is the most
likely place in our solar system beyond Earth to have life today,
and a landed mission would be the best way to search for signs
of life.”
The paper was authored by scientists from a number of other
NASA centers and universities, including the Johns Hopkins
University Applied Physics Laboratory, Laurel, Md.; University
of Colorado, Boulder; University of Texas, Austin; and the NASA
Goddard Space Flight Center, Greenbelt, Md. The team found
the most important questions clustered around composition:
what makes up the reddish “freckles” and reddish cracks that
stain the icy surface? What kind of chemistry is occurring there?
Are there organic molecules, which are among the building
blocks of life?
Additional priorities involved improving our images of Europa
- getting a look around at features on a human scale to provide
context for the compositional measurements. Also among the
top priorities were questions related to geological activity and
the presence of liquid water: how active is the surface? How
much rumbling is there from the periodic gravitational squeezes
from its planetary host, the giant planet Jupiter? What do these
detections tell us about the characteristics of liquid water below
the icy surface?
“Landing on the surface of Europa would be a key step in the
astrobiological investigation of that world,” said Chris McKay, a
senior editor of the journal Astrobiology, who is based at NASA
Ames Research Center, Moffett Field, Calif. “This paper outlines
the science that could be done on such a lander. The hope
would be that surface materials, possibly near the linear crack
features, include biomarkers carried up from the ocean.”
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