Life on Europa

What would a mission to Jupiter's moon find?

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Natural color image of Europa, one of Jupiter's four so-called Galilean moons.

Is there life on Europa, Jupiter's moon? Perhaps - but we may not know for years, or even decades, depending on the outcome of NASA budget wars that broke out before Congress went home for its August recess.

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We know very little about Europa. NASA's Voyager 2 and Galileo spacecraft flew by Jupiter's moon a dozen times and took pictures from space. But the Galileo mission was nearly 20 years ago, and Voyager 2 was in 1979. Still, the pictures Voyager 2 and Galileo sent home were enough to keep scientists guessing about what might lie beneath Europa's fractured, ice-covered world.

In fact, an all-star NASA science team speculates in a new study published in the journal Astrobiology that there are signs of a liquid water ocean under Europa's icy surface that could potentially be a home for microbial life.

Newer research, funded by both NASA and the National Science Foundation, has shown that microbes can survive in even the harshest environments – near the edge of underwater volcanoes in the deep oceans or in the iciest of conditions on Antarctica. So if there's a liquid ocean on Europa, there might also be microbial life.

When NASA sets out on a planetary science mission, it starts with the big science questions that need to be answered. So that's what a NASA "science definition" research team drawn from the agency's various centers did in their study – they laid out the biggest questions that need to be answered if NASA is going to land a spacecraft on Europa.

"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 the study's lead author, Robert Pappalardo, from NASA's Jet Propulsion Laboratory in California. "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 Astrobiology study on the big science questions for a Europa mission was put together by scientists from a number of NASA centers including the JPL, the Goddard Space Flight Center in Maryland and the Ames Research Center in California as well as NASA-funded research universities like the Johns Hopkins Applied Physics Lab in Maryland, the University of Colorado and the University of Texas.

Perhaps the first thing a NASA mission to Europa would look for is a marker of microbial life near fissures on the surface of the moon. "The hope would be that surface materials, possibly near the linear crack features, include biomarkers carried up from the ocean," said Chris McKay, from Ames and a senior editor for Astrobiology.

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Just as NASA did with the Mars Rover, a lander on Europa would take lots and lots of pictures up close – providing a "human-scale context" vastly different than the pictures from the Voyager 2 and Galileo flybys taken from space. A Europa rover would also look for geological activity as well as the presence of liquid water.

The American public is fascinated with planetary science. More than 30,000 Americans have now paid a small fee to sign up for a one-way trip to Mars a decade from now sponsored by a start-up foundation called the Mars One project. More than 100,000 people worldwide have signed up to spend the rest of their lives on Mars, the project's founder announced recently.

And while life-threatening details – like whether people will be exposed to lethal space radiation during the one-way trip to Mars or how the settlement will be permanently funded – are a long way from being answered, the response clearly shows that the public wants to explore the rest of our solar system. People are inspired by space travel and planetary science.

However, the White House and, to a lesser extent, parts of the House of Representatives are not. There is currently a three-way fight – between the House, the Senate and the White House - raging in Washington, D.C., over NASA's planetary science future that was on full display as the space agency's budget was debated in July.

The budget fight began when the White House submitted its fiscal year 2014 NASA budget to Congress. While the overall number was flat, the White House proposed to significantly cut the planetary science and space exploration portion of NASA's budget to make way for other priorities.

Then the House Appropriations Committee weighed in proposing to cut NASA's budget deeply, below President Barack Obama's request. "This proposal would challenge America's preeminence in space exploration," NASA Associate Administrator David Weaver wrote in a blog on the eve of the House panel vote. "We are especially concerned the bill cuts funding for space technology – the 'seed corn' that allows the nation to conduct ever more capable and affordable space missions."

Next, the House Science, Space, and Technology Committee proposed to cut NASA's budget even further, in line with sequestration guidelines. Its Senate counterpart restored those cuts, setting the stage for a budget shoot out when Congress returns in September. NASA's fiscal 2014 budget has to be finalized by the end of September.

So what's the future of a mission to Europa to see if life exists there beneath the icy surface? It depends. The White House's Office of Management and Budget doesn't see a need for such a mission. House appropriators, from both parties, clearly do – because they approved nearly $100 million more for planetary science (with cuts elsewhere to offset the increase)in NASA's budget than the White House did. The Senate has yet to say.

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"The nation's planetary science program has been under sustained attack from the White House budget cutters and remains in jeopardy," Rep. Adam Schiff, D-Calif., wrote in an unusually critical opinion piece recently attacking the White House for its NASA budget. "Time and again, deficit hawks in the Office of Management and Budget have targeted specific parts of the NASA portfolio for disproportionate cuts, and none more so than arguably the most successful of all NASA's recent achievements — planetary science."

Schiff explained why the House appropriators restored the money for planetary science in NASA's budget, which would allow NASA to begin planning for a Europa mission.

"Some in Washington have questioned why funding these missions is such a priority in an era of austerity and deficits. Plainly, the bureaucrats at OMB think the search for life on other planets to be an expensive, quixotic and dispensable activity," wrote Schiff, who sits on the Appropriations committee.

"Profoundly important research and development and all the economic benefits it brings will be forsaken if we abandon the field," he said. "Planetary science is about seeking the answers to questions as old as mankind – and perhaps older. Are we alone? What is the nature of the universe and our place in it? Americans come from a long line of explorers. Are we really content to take a back seat now?"

If there is microbial life on Europa – and NASA is allowed to start the search for it with a mission to Jupiter –it will depend on human life in Congress.