Why are people so excited about Jupiter's moon Europa? Water.
Despite being comparatively minuscule to our own planet, the frozen little moon contains two to three times as much water, much of it liquid, meaning the moon is potentially capable of supporting extraterrestrial life.
Image Credit: Kevin Hand (JPL/Caltech)
And that's why everyone is excited about NASA's submission of a budget request filed jointly with the White House to fund a future mission to Europa. Based on the current research, it's believed that such an interstellar road trip could put humanity within physical touch of one of the most likely close-by candidates for alien life.
How excited are scientists about this? io9 pulled this quote from Michael Shara, a curator at the Department of Astrophysics at the American Museum of Natural History, who told us about Europa:
If we can figure out a way of putting a probe through [Europa's] ice — and the ice may be hundreds of yards thick, it could be very difficult to do this — but if we could put a probe down that could melt its way through the ice, and then send out little submarines, who knows what we could find down there. It would be fascinating to go look. I think we have no choice but to go look. We must do it.
NASA engineer Adam Steltzner, who led the team of engineers who landed the Curiosity rover on Mars in August 2012, pretty openly said this is his dream project. And the budget request makes it crystal clear that going to Europa is a big future priority for NASA.
The bad news? The Europa budget is just $15 million — out of NASA's total $17.5 billion budget — which is nowhere near the investment NASA would need to make to send a rover to the watery moon. A project called the Europa Clipper could theoretically leave for the moon by 2025, over a decade from now, but that device would just be a reconnaissance probe rather than a lander, and would still cost around $2 billion. And it's small in comparison to previous spending. NASA spent some $155 million in the past two years investigating Europa, but at the behest of Congress rather than NASA's request. The technical challenges are difficult as well; Europa's ice could be kilometers thick, meaning that finding life could still be very difficult, if at all possible.
Still, NASA's request shows Europa is a growing priority and that landing on the body's surface may be possible and likely within our lifetimes.