Congress Wants Not One, But Two Europa Missions

Jupiter's moon Europa could be the best place in the Solar System to look for life beyond Earth. In fact, NASA scientists revealed this week that the moon's subsurface ocean could be similar to the oceans here on Earth. This boosts the chances that we could find life or at least the conditions to support life. As a result, Congress wants the agency to explore the icy moon, STAT.

Since Earth is the only example of life in the Solar System, scientists have long believed that to find life you must follow the water. Today, we know that without water there is no life. Research tells us that oceans may be a good place to incubate life because it has everything that life needs to survive. Whether it's frozen or boiling hot, wherever we find water (on Earth) we have found life.

Not that long ago, scientists thought oceans were unique to our planet, but now we know they are ubiquitous. We have evidence that oceans exist throughout the Solar System, and they are surprisingly Earth-like. So why is NASA so seemingly focused on Mars?

One word: budget. A mission to the outer Solar System could cost well over $1 billion dollars and planetary science hasn't received as much funding in recent years as some of the Mars programs have. Mars is much closer and thus easier to reach. NASA has spent the past five decades exploring the Red Planet, and understands the surface of Mars. Europa is further away, and will be a technological challenge.

The Viking missions to Mars have been the only missions so far to the Red Planet specifically designed to look for life. However, scientists didn't understand Martian chemistry and geology like they do today. When asked about the best place to look for life (Mars or Europa), Luther Beegle, deputy section manager for planetary science at NASA's Jet Propulsion Laboratory explains, "If there's active life in the Solar System today, it's probably on the bottom of Europa's ocean. However, getting through the ice to gather evidence is going to be extremely difficult."

Congress, and in particular the House Appropriations subcommittee (which oversees NASA's budget) is convinced we need to go to Europa, and fast. Subcommittee chairman John Culberson (R-Texas), has his sights set on Europa and is working to ensure NASA has the budget for not one, but two missions: an orbiter and a lander.

According to a new House appropriations bill released this week, Culberson and his committee want to allocate $260 million for Europa mission planning and development in 2017; a significant increase over the $49.6 million NASA asked for.

In addition to the Europa Multi-Flyby Mission (an orbiter) already in development, Culberson would like to see NASA send a lander to explore the moon's icy surface. There are challenges to having these two components in one single mission, which is why Congress is so adamant on two.

Congress wants NASA to send an orbiter first, which would complete at least 45 flybys of the moon's surface. The spacecraft would also sample the radiation levels around Europa due to its close proximity to Jupiter. All of this data will be used to pick out the best landing spot for a lander to touchdown approximately two years later.

In a subcommittee hearing this week, Culberson explained why Europa should be a priority. "We have increased funding for NASA's planetary programs," he said. "The mission to Europa is incredibly important as shown in past decadal surveys. There's a high likelihood of finding life and if such a discovery is made, it will be a transformative moment in human history."

NASA has yet to approve a lander, and estimates that the orbiter will launch sometime in the next decade. Congress has other plans. It proposes that an orbiter launch no later than 2022, followed by a lander in 2024.

Why is Europa so fascinating? We know that life needs water, but it also needs energy. That energy can come from interactions between seawater and a rocky seafloor. "The cycling of oxygen and hydrogen in Europa's ocean will be a major driver for Europa's ocean chemistry and any life there, just as it is on Earth," explains Steve Vance, a researcher from JPL.

Here on Earth, our oceans make hydrogen through a process called serpentinization. Seawater seeps into cracks in the seafloor, reacting with various minerals to produce two ingredients essential to life: hydrogen and heat.

A team of researchers at JPL compared Europa's potential for producing hydrogen and oxygen using computer models. Their results showed the icy moon was just as capable as Earth. The findings were published this week in the Geophysical Research Letters.

Jupiter constantly bathes Europa in radiation. While this would not be a good thing for surface life, this is essential to creating the perfect conditions for life below the surface. The radiation causes Europa's icy surface to crack and split, breaking down water molecules in the process. This leads to the production of oxidants, which are continuously cycled throughout the moon's interior.

"If the rock is cold (like we find on Europa), it's easier to fracture," explains Vance. "This allows for a huge amount of hydrogen to be produced by serpentinization that would balance the oxidants — which are also necessary to life, but can be toxic to life if they are too abundant — in a ratio comparable to that in Earth's oceans."

Bottom line: Europa is so interesting even congress agrees we should explore it.