“It’s like the person who loses their keys and only looks for them below the streetlight,” said David Jewitt, a planetary scientist at UCLA who studies comets.
But funds for planetary science are limited — and even those who favor a broader search admit that Mars remains the most practical site to explore.
A mission to Europa, for example, would take about six years to reach its destination. Curiosity’s trip to Mars takes about eight months.
Europa has other drawbacks too: For one, particles flung into space by Jupiter’s magnetic field would likely fry a spacecraft’s electronics in a matter of weeks, said Richard Greenberg, who studies the frozen moon at the University of Arizona.
“Personally, I love Europa,” he said. “But objectively, both it and Mars are great places to look for life.”
Regardless of whether life can be found beyond Earth, Mars exploration boosts U.S. prestige.
“A lot of the warmest feelings people have had around the world have had to do with the space program,” Munson said. “It’s hard to put a value on that.”
Space exploration is the ultimate status symbol. China and India have signaled their technological aspirations by establishing space programs. So have Iran, Pakistan, Venezuela, Israel, Mexico and dozens of other countries.