Artist conception of water vapor plumes coming from beneath the thick ice of Jupiter’s moon Europa. The plumes have not been definitively detected, but Hubble Space Telescope images make public earlier this month appear to show plume activity in an area where it was detected once before.  How will this finding affect decision-making about a potential NASA Europa lander mission? (NASA)

As I prepare for the Astrobiology Science Conference (Abscicon) next week in Arizona, I’m struck by how many speakers will be discussing Europa missions, Europa science, ocean worlds and habitability under ice.  NASA’s Europa Clipper mission to orbit that moon, scheduled for launch to the Jupiter system in the mid 2020s, explains part of the interest, but so too does the unsettled fate of the Europa lander concept.

The NASA Science Definition Team that studied the Europa lander project will both give a science talk at the conference and hold an afternoon-long science community meeting on their conclusions.  The team argued that landing on Europa holds enormous scientific promise, most especially in the search for life beyond Earth.

But since the Europa lander SDT wrote its report and took its conclusions public early this year, the landscape has changed substantially.  First, in March, the Trump Administration 2018 budget eliminated funding for the lander project.  More than half a billion dollars have been spent on Europa lander research and development, but the full project was considered to be too expensive by the White House.

Administration budget proposals and what ultimately become budget reality can be quite different, and as soon as the Europa lander was cancelled supporters in Congress pushed back.  Rep. John Culberson (R-Tex.) and chair of the House subcommittee that oversees the NASA budget, replied to the proposed cancellation by saying “NASA is a strategic national asset and I have no doubt NASA will receive sufficient funding to complete the most important missions identified by the science community, including seeking out life in the oceans of Europa.”

More recently, researchers announced additional detections of plumes of water vapor apparently coming out of Europa — plumes in the same location as a previous apparent detection.  The observing team said they were confident the difficult observation was indeed water vapor, but remained less than 100 percent certain.  (Unlike for the detection of a water plume on Saturn’s moon Enceladeus, which the Cassini spacecraft photographed, measured and flew through.)

So while suffering a serious blow in the budgeting process, the case for a Europa lander has gotten considerably stronger from a science and logistics perspective. 

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