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Next stop, Europa

NASA continues search for water, and life, in space

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April 22nd, 2014
Saturn's moon, Europa
Saturn's moon, Europa

The space shuttle may be retired, but NASA has been busy all the same. On the heels of a successful unmanned landing on Mars in August 2013, the space agency has trained its sights on the outer reaches of our solar system and, more specifically, the satellites of Jupiter.

As far as astronomers can tell, the planet has upwards of 60 moons. Europa is the one with the greatest exploratory potential.

“We want to go to Europa because it’s a unique destination in the solar system,” says Curt Niebur, lead scientist with NASA’s New Frontiers Program. “This is primarily the case because a previous mission showed that it has a crust of water ice, and below that crust there is likely a global liquid ocean.”

In 1995, NASA launched its first expedition to Jupiter, during which the satellite spacecraft Galileo performed a dozen close-proximity flybys of Europa. 

Then something happened…

It was on one such orbit around the icy moon that scientists noticed something strange.

“As Galileo approached Europa, we realized that the readings from its onboard magnetometer (a device used to measure magnetic fields) had completely reversed,” Niebur explains. “And as the spacecraft moved away from Europa, it reversed again.”

According to Niebur, the only thing that could make that happen is the presence of a significant amount of salt water.

“The salty water on Europa acts as a conductor,” he says, “and in that conductor, the magnetic field of Jupiter creates the secondary magnetic field that caused Galileo’s magnetometer to reverse. In other words, we have strong evidence that this moon has an ocean.”

NASA’s scientists spent 12 years crunching the bonanza of data that Galileo had sent back to Earth. What they discovered was beyond anything they could have imagined.

Europa is indeed encased in a crust of ice up to 100 km thick, but scientists predict that underneath it is a vast ocean of relatively warm, salty water. Niebur and his colleagues suspect that this could be an ideal environment for life.

“The three main ingredients you need for life are an energy source (heat from Jupiter), liquid water, and the necessary chemistry—elements like nitrogen and oxygen,” he says. “We believe that Europa has the well-established, stable conditions for these things to combine and create life.”

In fact, Niebur argues that because Europa is roughly three billion years old, the kinds of life existing in this ocean may be much more complex than mere bacteria—a hypothesis that NASA is still a long way off from proving. 

Huge hurdles ahead

The real challenge is going to be landing on the moon to confirm it.

The sheer distance from Earth to Europa is a hurdle in itself. At over 500 million miles, the journey will take a satellite six years to complete.

And once there, landing will probably be impossible.

On the surface, scientists have to deal with the tremendous magnetic radiation given off by Jupiter, which in Niebur’s estimate is enough to kill a human being in less than 10 minutes. NASA has yet to develop equipment capable of withstanding this sort of abuse.

Further complicating matters is the surprisingly thin budget the agency’s researchers have at their disposal. In March, the Obama Administration allotted $15 million for the project with no word on additional funding in the future.

Of course, Niebur is quick to point out that the mission remains in the early planning stages. 

Right now, NASA doesn’t foresee a launch until at least the mid-2020s, meaning that the arrival time will be several years after that.

This is no big deal for Niebur. As he puts it, scientists who work on the outer planets are used to the long-term, where patience is the name of the game.

In the meantime, he wants to focus on what this mission might ultimately reveal.

“Our goal is to determine whether Europa is a place capable of supporting life and whether or not life actually does exist there,” he says. “This isn’t so much about whether we can some day live there. The purpose is to learn about our solar system. 

“We know Earth has life, and if we can prove the same thing on a place like Europa, then we’ve vastly increased the likelihood that life exists elsewhere in the universe.”

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