Ever since the late 1990s, when NASA's Galileo mission to Jupiter gave scientists their first really good images of Jupiter's moon, Europa, they've been wanting to study it in detail. That's when they first realized that no only is Europa's surface composed of ice, it's composed of water ice. As they studied the Galileo data and the data of other probes to the Jovian system, that is, Jupiter and its 63 moons, they realized that underneath its icy crust, Europa has an ocean of liquid water. NASA scientists are clear that they don't know everything about extra terrestrial life, but they do know that here on Earth, almost every place where there's liquid water and some form of energy, there's life. So, with the prospect of another planetary body with a water ocean, NASA scientists are chomping at the bit to get back to Europa. It is, by far, they have determined, the most promising place in the solar system to look for the first proof of extra terrestrial life.
Well, they've made their case. NASA's mission concept: conducting a detailed survey of Europa and investigating its habitability, has made it through its first major review by NASA administrators and is now entering the development phase the agency calls "formulation". When they use the term "habitability", by the way, they're not talking about for humans. They mean, could Europa support life of any kind?
"Today we're taking an exciting step from concept to mission, in our quest to find signs of life beyond Earth," says associate administrator for NASA's Science Mission Directorate in Washington, John Grunsfeld. "Observations of Europa have provided us with tantalizing clues over the last two decades," he says, "and the time has come to seek answers to one of humanity's most profound questions."
The plan for the, so far, unnamed mission, is for a spacecraft to be launched to the Jupiter in the 2020s. The journey there will take several years. Once it arrives, the spacecraft will orbit Jupiter about every two weeks, which will allow for 45 planned flybys of Europa. During these flybys the spacecraft will image the Europa's icy crust with high resolution cameras. There is evidence that indicates that Europa may send geysers of water into space. If this is verified, the Europa probe will also be fitted with sensors that will allow it to analyze these geysers as it flies through them. This would allow NASA scientists to do things like verifying that the liquid below Europa's icy crust is, in fact, water, and if so, what's dissolved in it (is it salt water or fresh) and, possibly, what's swimming around in it.
"It's a great day for science," says Europa program executive at NASA Headquarters in Washington, Joan Salute. "We are thrilled to pass the first major milestone in the lifecycle of a mission that will ultimately inform us on the habitability of Europa."