Next week, scientists will gather at the Astrobiology Science Conference (AbSciCon) in Mesa, Arizona. A quick glance at the 63 session topics shows Europa (and other ocean worlds) will be a hot topic of discussion. And it’s easy to see why.
Earlier this month, two NASA missions gave us new insight into the icy, wet worlds of Enceladus and Europa. Enceladus stole most of the headlines, but the new data from Europa is promising. The Hubble Space Telescope found more evidence of plumes erupting from the Jupiter moon. Images captured by the telescope in 2016 show what appears to be a plume of material erupting from the moon’s surface. In the same spot a possible plume erupted in 2014.
“If there are plumes on Europa, as we now strongly suspect, with the Europa Clipper we will be ready for them,” said Jim Green, NASA’s Director of Planetary Science. The Europa Clipper is set for launch in the early 2020s. Add a couple of years of flying in space, and it’ll be in the mid-to-late 2020s before the spacecraft reaches Jupiter.
But NASA is already thinking about the next mission to Europa. One that has the best chance at answering the question. Are we alone? In February, NASA received a report detailing a Europa Lander Concept.
On March 19, NASA held the first of two town hall meeting at the 2017 Lunar and Planetary Science Conference (LSPC) at The Woodlands, Texas. Here, scientists discussed the report and offered feedback. On April 23 (Sunday), the second town hall will be held at AbSciCon.
Quick note: Despite not making the proposed budget from the White House, the NASA team studying the lander mission will continue their work. “We still have enough funding to make it through the end of the year for development,” said JPL’s Barry Goldstein according to Space. “We’re going to pursue the mission concept review and let the chips fall where they may as we proceed.”
Current progress on the budget in Congress is at a standstill with the Trump Administration contemplating a government shutdown over his controversial Border Wall proposal. The likely outcome will be a continuing resolution with funding levels set from last year for all agencies. Welcome to Washington.
Let’s take a deeper look at the objectives of a Europa lander mission and how the mission will deal with planetary protection protocols.
The Europa Lander mission objectives
Concept art of the Europa lander sitting on the surface. Credit: NASA
This report highlights three main goals for the Europa Lander Mission.
First, search for evidence of life on the icy moon. The report emphasizes one piece of evidence isn’t enough to answer the fundamental life question.
“No single line of evidence is sufficient for concluding that life has been detected. A robust detection of life requires several complementary and redundant biosignatures.”
Nine different investigations will be conducted to hunt for signs of life. The search will range from amino acids to carbon and inorganic indicators. Detecting and characterizing microscopic and macroscopic structures is another vital part.
The second goal will assess Europa’s habitability of Europa using in situ techniques (measurements taken within the environment around the lander) only possible with a lander mission.
There are a lot of similarities between the first and second goal, but the report stresses habitability doesn’t mean life.
“A habitable environment, however, could well be devoid of life if conditions for the origin of life were not satisfied. In other words, life requires habitability, but habitability does not require life.”
This distinction is especially important if the results of the first goal find no biosignatures. What would the lack of biosignatures at the lander site mean for all of Europa? Was the lander just unlucky?
Understanding the habitability of Europa is a must. Maybe Europa doesn’t have all the right stuff for life. Or maybe it does, and life still can’t be found. Which raises even more questions. But could also help us better understand what makes Earth so special. How did life begin and evolve here?
The third goal will pave the way for future missions to explore distant worlds. Again, there’s plenty of crossover between the other two goals, but the goal here is to gather science to help the next wave of robotic and human explorers. That includes measuring the moon’s physical properties and taking a closer look at dynamic processes that shape Europa’s surface. Think physical, chemical, thermal at the surface and below.
What scientists learn on this first visit to Europa will help future missions. They may find staying on the icy surface isn’t ideal for exploring an icy world with an ocean underneath. Future missions to Europa could be designed to move downward into the icy shell.
Planetary Protection and Europa
Workers going over Mars Exploration Rover-1 at Kennedy Space Center in 2003. Credit: NASA
Any mission to another world is a challenge. One of the biggest is making sure we don’t bring a piece of Earth with us. Especially on a mission searching for life. We want to protect any potential ecosystems, plus avoid false positives in our quest to find out if we are alone in the universe.
How would NASA make sure tiny Earth microbes aren’t hitching a ride with the Europa lander? Before launch, the hardware would be heated to temperatures at or over 250 degrees Fahrenheit for days in a controlled humidity environment in a process called dry-heat microbial reduction (DHMR).
A Viking lander getting ready for dry heat sterilization back in the 1970s. Credit: NASA
Then, the entire lander would be wrapped in a biobarrier and go through another round of DHMR. Some of the hardware, such as batteries, would also be irradiated to meet Planetary Protection requirements.
Scientists will keep studying ways to improve Planetary Protection protocols to make sure any potential life signatures found on another world aren’t from our own.
A Europa lander is a ways off. This is still very much in the concept phase. Plus, the uncertainty surrounding NASA’s budget will continue to hang over the mission. But work continues until the money runs out, and that won’t happen until the end of the year.
Ocean worlds like Europa, Enceladus and others are prime targets for the search for life. The Europa Clipper mission will tell us much more about the icy, wet world circling Jupiter. And hopefully, find a nice landing spot for the Europa lander.